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Seminars (BSM)

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Event When Speaker Title Presentation Material
BSMW01 11th January 2012
10:00 to 11:00
Geometry and Connectedness of Heterotic String Compactifications with Fluxes
I will discuss the geometry of heterotic string compactifications with fluxes. The compactifications on 6 dimensional manifolds which preserve N=1 supersymmetry in 4 dimensions must be complex conformally balanced manifolds which admit a now-where vanishing holomorphic (3,0)-form, together with a holomorphic vector bundle on the manifold which must admit a Hermitian Yang-Mills connection. The flux, which can be viewed as a torsion, is the obstruction to the manifold being Kahler. I will describe how these compactifications are connected to the more traditional compactifications on Calabi-Yau manifolds through geometric transitions like flops and conifold transitions. For instance, one can construct solutions by flopping rational curves in a Calabi-Yau manifold in such a way that the resulting manifold is no longer Kahler. Time permitting, I will discuss open problems, for example the understanding of the the moduli space of heterotic compactifications and the related problem of determining the massless spectrum in the effective 4 dimensional supersymmetric field theory. The study of these compactifications is interesting on its own right both in string theory, in order to understand more generally the degrees of freedom of these theories, and also in mathematics. For instance, the connectedness between the solutions is related to problems in mathematics like the conjecture by Miles Reid that complex manifolds with trivial canonical bundle are all connected through geometric transitions.
BSMW01 11th January 2012
11:30 to 12:30
M Larfors A ten-dimensional action for non-geometric fluxes
In ten- and four-dimensional supergravities, the descriptions of non-geometric configurations are different. In the former, non-geometry arises as naively non-single valued supergravity fields. In the latter, new terms, coming from non-geometric Q- and R-fluxes, appear in the four-dimensional potential. In this talk, it is shown that a ten-dimensional field redefinition results in a Q-flux term in the NSNS Lagrangian. This change of field basis is inspired by generalized geometry. We argue that this new field basis provides a good description of certain non-geometric configurations. In particular, using the new basis, a dimensional reduction can be performed, in which the Q-flux term gives rise to the expected term in the four-dimensional potential. We also discuss the global issues of this set-up.
BSMW01 11th January 2012
14:00 to 15:00
Supergravity as generalised geometry
We show how extensions of conventional differential geometry, so called "generalised geometry", give a natural way of formulating type II and eleven-dimensional supergravity theories, unifying the bosonic fields and symmetries. There is a natural action of the U- and T-duality groups E_d(d) and O(d,d) and the formalism shows that the supergravity theories have an enhanced local symmetry. By introducing the analogue of the Levi-Civita connection we find that the action and equations of motion simplify, writable in terms of a generalised Ricci tensor. The connection also encodes the supersymmetry variations and fermionic equations of motion. There are interesting implications for describing supersymmetric backgrounds and connections to the embedding tensor formalism.
BSMW01 11th January 2012
15:30 to 16:30
Stringy corrections with B-field
I'll discuss the inclusion of B-field in the higher derivative corrections in the effective theories, its possible applications and interpretations.
BSMW01 11th January 2012
16:30 to 17:30
Reductions with reduced supersymmetry using generalized geometry
We will discuss reductions of M-theory and type II theories to four dimensions preserving N=1 and N=2 supersymmetry, in the language of exceptional generalized geometry. We will introduce the relevant structures which encode the NSNS and RR degrees of freedom, discuss the geometry of their orbits under the action of the U-duality group (i.e., the moduli space metrics), and how they enter in the superpotential.
BSMW01 12th January 2012
10:00 to 11:00
D-brane/O-plane effective actions, disc amplitudes and T-duality
I will be discussing the computation of superstring scattering amplitudes in the presence of D-branes and orientifold planes. The results encode certain terms in the low energy effective actions of space-time fields localized on branes/planes. I will describe some of these interactions and show how they restore compatibility with T-duality.
BSMW01 12th January 2012
11:30 to 12:30
M-branes and String structures
I will describe the relation of the C-field to String structures, which are essentially Spin structures on loop space, and explain how these structures capture certain geometric and topological aspects of M-branes.
BSMW01 12th January 2012
14:00 to 15:00
T Hartman Higher Spin Gravity and 2d CFTs
Higher spin gravity in three dimensions is holographically dual to a two-dimensional CFT with extended conformal symmetry, known as a W-algebra. This raises the possibility of tackling difficult questions in holography or quantum gravity by exploiting the W-algebra to do exact computations at all values of the coupling. I will review the status of various higher spin dualities, and for the case of AdS_3, describe the detailed matching of the spectrum and the CFT interpretation of higher spin black holes.
BSMW01 12th January 2012
15:30 to 16:30
E Diaconescu Lagrangian cycles and knots at large N
Lagrangian cycles will be constructed for algebraic knots in the context of large N duality via conifold transitions. It will be explained how this construction yields a physics derivation of a conjecture of Oblomkov and Shende on HOMFLY polynomials and plane curve singularities. This is joint work with V. Shende and C. Vafa.
BSMW01 12th January 2012
16:30 to 17:30
Line bundle Standard Models
I will discuss recent work constructing heterotic standard models by compactifying on smooth Calabi-Yau three-folds in the presence of purely Abelian internal gauge fields. The simple construction of these models allows for a large-scale, algorithmic approach to the study of heterotic string vacua. In particular, a systematic search over complete intersection Calabi-Yau manifolds with less than six Kahler parameters has lead to over 1000 such models with exact Standard Model spectra. In addition, the presence of additional global U(1) symmetries, leads to a rich variety of geometric/phenomenological structures and provides a window into a larger moduli space of non-Abelian vector bundles.
BSMW01 13th January 2012
10:00 to 11:00
V Pestun Instanton calculus in quiver gauge theories
BSMW01 13th January 2012
11:30 to 12:30
String Theory and the Moonshine Programme
In some occasions, certain finite groups display a close connection to certain modular objects defined on the upper-half plane. The most well-known of such a relation between these two distinct mathematical structures is the so-called monstrous moonshine, relating the largest sporadic group to a set of modular functions. String theory, with its power to geometrise automorphic objects, has been proven instrumental in providing insights into these mysterious relations. Recently, certain unexpected relation with various similarities to the monstrous moonshine has been discovered. In this talk I will review these recent mathematical developments, while putting extra focus on the role played by string theory.
BSMW01 13th January 2012
14:00 to 15:00
Wall-crossing, dilogarithm identities and the QK/HK correspondence
I will explain how the wall-crossing behaviour of D-brane instantons in type II Calabi-Yau compactifications is captured by a certain hyperholomorphic line bundle over a hyperkähler manifold. This construction relies on a general duality between 4n-dimensional quaternion-Kähler and hyperkähler spaces with certain continuous isometries. The continuity of the moduli space metric across walls of marginal stability is encoded in non-trivial identities for the Rogers dilogarithm, which are shown to be a consequence of the motivic Kontsevich-Soibelman wall-crossing formula. Finally, I will offer some speculations on how the construction is modified in the presence of NS5-brane effects.
BSMW01 13th January 2012
15:30 to 16:30
L Hollands A 4d-2d correspondence for Sicilian quivers
In the last few years a wealth of novel properties of N=2 supersymmetric gauge theories has been uncovered. In particular, much has been learned about the strong coupling limits of these gauge theories through a dual two-dimensional perspective in terms of Riemann surfaces. In this talk I will discuss a quantitative check of this 4d-2d correspondence by computing the instanton partition function of an SU(2) gauge theory that is associated to a higher genus Riemann surface and its corresponding conformal block. This exercise will reveal a better understanding of the correspondence between four-dimensional instanton partition functions and two-dimensional conformal blocks.
BSMW01 13th January 2012
16:30 to 17:30
A Dabholkar Localization and Exact Quantum Entropy of Black Holes
BSM 18th January 2012
16:00 to 17:00
S Vandoren M5 branes, 4d/2d correspondence, and 5D SYM on a torus
BSM 19th January 2012
12:00 to 13:00
Generalized quark-antiquark potential of N=4 SYM at weak and strong coupling
BSM 19th January 2012
14:00 to 15:00
Fundamental Structures of M(brane) Theory
BSM 20th January 2012
12:00 to 13:00
J Manschot BPS Invariants of Rational Surfaces
BSM 25th January 2012
16:00 to 17:00
New instability of non-extremal black holes: spitting out supertubes
We search for stable bound states of non-extremal rotating three-charge black holes in five dimensions (Cvetic-Youm black holes) and supertubes. We do this by studying the potential of supertube probes in the non-extremal black hole background and find that generically the marginally bound state of the supersymmetric limit becomes metastable and disappears with non-extremality (higher temperature). However near extremality there is a range of parameters allowing for stable bound states, which have lower energy than the supertube-black hole merger.

Angular momentum is crucial for this effect. We use this setup in the D1-D5 decoupling limit to map a thermodynamic instability of the CFT (a new phase which is entropically dominant over the black hole phase) to a tunneling instability of the black hole towards the supertube-black hole bound state. This generalizes the results of "Moulting Black Holes", which mapped an entropy enigma in the bulk to the dual CFT in a supersymmetric setup.

BSM 26th January 2012
12:00 to 13:00
Singularity structure and massless dyons of pure N = 2, d = 4 theories with SU(r+1) and Sp(2r) gauge groups
We study pure Seiberg-Witten theories with SU(r+1) and Sp(2r) gauge groups with no flavors. We study singularity loci of moduli space of the Seiberg-Witten curve. Using exterior derivative and discriminant operators, we can find Argyres-Douglas loci of the SW theory. We also compute BPS charges of the massless dyons of SU and Sp SW theory. In a detailed example of C_2=Sp(4), we find 6 points in the moduli space where we have 2 massless BPS dyons, and 3 of them give Argyres-Douglas loci. We show that BPS charges of the massless dyons jump as we go across Argyres-Douglas loci, giving an explicit example of Argyres-Douglas loci living inside the wall of marginal stability.
BSM 26th January 2012
14:00 to 15:00
Permutation groups, Mock modular forms, K3 surfaces and Moonshine (I)
I will discuss connections between sporadic groups and modular forms including the original connection between the monster and the modular function J, the more recent connections between the Mathieu group M24 and the mock modular form appearing in the decomposition of the elliptic genus of K3 surfaces into N=4 characters, and some work in progress which generalizes this latter connection to other groups and Jacobi forms.
BSM 27th January 2012
12:00 to 13:00
Permutation groups, Mock modular forms, K3 surfaces and Moonshine (II)
I will discuss connections between sporadic groups and modular forms including the original connection between the monster and the modular function J, the more recent connections between the Mathieu group M24 and the mock modular form appearing in the decomposition of the elliptic genus of K3 surfaces into N=4 characters, and some work in progress which generalizes this latter connection to other groups and Jacobi forms.
BSM 27th January 2012
14:00 to 15:00
Permutation groups, Mock modular forms, K3 surfaces and Moonshine (III)
BSM 31st January 2012
14:00 to 15:00
Chern-Simons Theories with Vector Matter
We investigate Chern-Simons theories coupling to vector matter. These kinds of models are quite interesting in the following sense. Firstly, they provide us with infinitely many interacting conformal field theories (CFT) with Lagrangian description, which enables us to study CFT in a direct calculation. Secondly, they are likely to be dual to higher spin theories in AdS4 beyond the conjecture by Klebanov-Polyakov. After a belief introduction of this background, I will talk about U(N) Chern-Simons theories coupling to vector-like (fundamental/anti-fundamental) matter(boson or fermion). It turns out that these kinds of models can be exactly solved in the 't Hooft limit by employing a standard large N technique. I will explain the details on this when the matter includes pure fermion or boson. If time permits, I will talk about the case including both in a supersymmetric way, which is work in progress.
BSM 1st February 2012
16:00 to 17:00
Chern-Simons and ABJM with Boundary
Motivated by considering M2-branes ending on M5-branes, we consider the ABJM theory with a boundary. The addition of a boundary to a Chern-Simons theory is non-trivial, in particular the bulk action is only gauge invariant up to a total derivative. For pure Chern-Simons theories it is possible to impose boundary conditions which leads to the well-known relation to WZW models. However for Chern-Simons plus matter theories, the situation is more complicated. Instead, we show how to add boundary degrees of freedom to restore the gauge symmetry, and this turns out to also lead to a type of WZW model on the boundary.
BSM 2nd February 2012
11:30 to 12:30
S Kim Instantons and M5-branes
We study an index which counts BPS bound states of instanton particles in 5d maximal SYM, and use it to explore the 6d (2,0) SCFT for M5-branes compactified on a circle in its Coulomb and symmetric phases.
BSM 2nd February 2012
14:00 to 15:00
Yangian invariant scattering amplitudes in ABJM theory
We study the scattering amplitudes of ABJM theory and discuss what they have in common with the amplitudes of the d=4, N=4 super-Yang-Mills theory. The main themes will include BCFW-like recursion formula, Grassmannian integral formula for all tree amplitudes and Yangian invariance vs dual superconformal invariance. We will also comment on possible connections to polygonal Wilson loops and twistor string theory.
BSM 7th February 2012
12:00 to 13:00
Automorphic forms on SL(3) and higher rank groups
I'll give an overview of automorphic forms beyond SL(2), explaining some of the highlights of the theory and several of its fundamental unresolved challenges. I will keep to the analytic side, emphasizing the impact of the Langlands' program and also some results which have been useful in string theory.
BSM 7th February 2012
14:00 to 15:00
From magics towards a "science" of exceptions
In classification problems one encounters often small sets of exceptional cases. Their pattern might be common to several such endeavours. Examples will be given from Symmetry to Topology and to Physics.
BSM 8th February 2012
16:00 to 17:00
Novel geometries from supersymmetric near-horizon solutions
Spinorial geometry techniques can be used to classify the near-horizon geometries of supersymmetric black holes in String/M-theory. I will illustrate this by presenting the classification of near horizon geometries in IIB supergravity coupled to a non-zero self-dual 5-form. The resulting geometries are generically described by a restricted Calabi-Yau with (hidden) torsion structure. Examples of such solutions will be considered, including a large class of AdS solutions.
BSM 9th February 2012
11:30 to 12:30
P P Cook One-dimensional solutions of M-theory
It has been argued that the generalised Kac-Moody algebras E11 and E10 encode the symmetries of M-theory. One may wonder whether a conjecture relating two imperfectly understood constructions can be put to good use. This talk will be a pedagogical introduction to a technique on the Kac-Moody side that reconstructs well-known supergravity solutions, albeit smeared down to one-dimension. The solutions emerge from a small corner of E11 but the technique may be applied to a much larger sector of E11 and used to propose exotic M-theory solutions.
BSM 15th February 2012
16:00 to 17:00
E O Colgain Fermionic T-duality
Despite AdS5 S5 being self-dual under a combination of bosonic and fermionic T-dualities, the same has yet to be said for AdS4 CP3. However, evidence from D=3 scattering amplitude calculations hint strongly at some self-duality. We explain the obstacles in the context of pp-waves and the D1-D5 near-horizon and comment on whether beta-deformed SYM inherits the same symmetries.
BSM 16th February 2012
11:30 to 12:15
Supersymmetric Double Field Theory: Stringy Reformulation of Supergravity
This talk aims to illustrate our recent supersymmetric extension of double field theory and its connection to supergravity. In terms of novel stringy differential geometry we propose, our action consists of five simple terms - two bosonic plus three fermionic - and manifests not only diffeomorphism and one-form gauge symmetry of B-field, but also O(10,10) T-duality as well as a direct product of two local Lorentz symmetries, SO(1,9) times SO(9,1). A gauge fixing that identifies the double local Lorentz groups reduces our action to the N=1 supergravity in ten dimensions.
BSM 16th February 2012
14:00 to 14:45
H Godazgar M-theory dualities and generalised geometry
BSM 16th February 2012
15:00 to 15:45
C Strickland-Constable E_d(d)xR^+ Generalised Geometry and 11D Supergravity
It is well known that dimensional reductions of eleven-dimensional supergravity have unexpected hidden symmetries. E_d(d)xR^+ genealised geometry provides a unified geometrical formulation of the internal sector of the theory, in which these symmetries appear naturally as structure groups. The construction is exactly analogous to ordinary Riemannian geometry, but with an enlarged tangent space. In particular, using the analogue of the Levi-Civita connection, the bosonic action and equations of motion can be expressed neatly as Einstein gravity for a generalised curvature tensor. Supersymmetry also appears in the process and the fermionic sector can be concisely reformulated in terms of the generalised connection. The talk will review the details of this formalism as well as discussing some explicit examples in particular dimensions.
BSM 16th February 2012
16:00 to 17:00
Informal discussion session on generalised geometry
BSM 17th February 2012
14:00 to 15:00
L Bao Gauge theory duality from M-theory and topological vertex
A gauge theory duality between the low energy effective theory of 5D N=1 SU(N)^{M-1} and SU(M)^{N-1} linear quiver gauge theories compactified on S^1 will be expolored in this talk. The duality is found by using both the Seiberg-Witten formalism and the topological vertex formalism. The duality map between the gauge theory parameters will be given. I will also discuss some implications of this duality in the context of the AGT conjecture.
BSM 21st February 2012
11:30 to 12:30
M Yamazaki Z[3d gauge theory]=Z[3-manifold]
We summarize our recently proposed correspondence between 3d N=2 gauge theories and 3d manifolds. If time permits, we also comment on connections with cluster algebras and dimer models.
BSM 21st February 2012
14:00 to 15:00
Factorization of N=2 theories partition functions on the squashed 3-sphere
We show that partition functions of N=2 theories on the squashed 3-sphere can be factorized into pairs of vortex theories defined on the two copies of R^2 x S1, corresponding to the two degeneration limits of the ellipsoid. We comment on how the ellipsoid partition function appears to provide the modular invariant non-perturbative completion of the vortex theory. We conclude with the geometrical engineering of the vortex theory.
BSM 22nd February 2012
16:00 to 17:00
Automorphic properties of string theory amplitudes in various dimensions
Maximally supersymmetric string theory compactified on d-dimensional torus is invariant under the non-perturbative U-duality groups E_{d+1}(Z). We will present the construction of the automorphic functions relevant for the supersymmetric protected BPS interactions in the low-energy expansion of maximal supersymmetric effective action in various dimensions. We will show that the support of the non-vanishing Fourier coefficients for these automorphic form is given by the expected BPS conditions one can derive from the supersymmetric conditions.
BSM 23rd February 2012
11:30 to 12:30
Enhanced ${\cal N}=8$ Supersymmetry of three-algebra ABJM Theory
By three-algebra ABJM theory I refer to any ${\cal N} = 6$ supersymmetric Chern-Simons matter theory. In this talk I show that if a three-algebra ABJM theory has a covariantly constant unitary monopole operator carrying two symmetric three-algebra indices, then this implies that this ABJM theory has hidden ${\cal N} = 8$ supersymmetry.
BSM 23rd February 2012
14:00 to 15:00
C Saemann M-branes and loop spaces
I will show how loop space can be used in the description of M5-branes. I will focus mainly on the description of self-dual strings as well as a self-dual string analogue of magnetic bags. I will develop a Nahm transform for both cases and construct a number of explicit solutions. I will also show how loop space gives a natural interpretation to a recently proposed set of N=(2,0) supersymmetric equations which might describe M5-branes.
BSM 29th February 2012
16:00 to 17:00
Double sigma models and double field theory
I will show how the equations of motion of double field theory can also be derived as the one-loop background field equations of a double sigma model, both being the vanishing of the generalised Ricci tensor. This raises the possibility of deriving higher order corrections to double field theory from a sigma model approach.
BSM 1st March 2012
11:30 to 12:30
M2/M5 systems and 5d SYM
The six-dimensional (2,0) M5-brane CFT was recently conjectured to be obtainable as the strong-coupling limit of five-dimensional, maximally supersymmetric Yang-Mills theory. In this talk we will first review the arguments leading to this claim. We will then present new evidence in its favour through the study of the M2/M5 bound state, which provides an M-theoretic realisation of the Myers brane-polarisation effect.
BSM 1st March 2012
14:00 to 15:00
C Keeler Fluid-Gravity Duality at a Cutoff Surface
We show by explicit construction that for every solution of the incompressible Navier-Stokes equation in $p+1$ dimensions, there is a uniquely associated "dual" solution of the vacuum Einstein equations in $p+2$ dimensions. We consider both a "near-horizon" limit in which $\Sigma_c$ becomes highly accelerated, and a long-wavelength hydrodynamic limit. We show that the near-horizon expansion in gravity is mathematically equivalent to the hydrodynamic expansion in fluid dynamics, and the Einstein equation reduces to the incompressible Navier-Stokes equation.
BSM 2nd March 2012
11:30 to 12:30
Instantons and Curve Counting
We review how the counting of BPS states of D-branes in Type IIA string theory can be captured by enumerating the instanton solutions in a six-dimensional noncommutative N=2 gauge theory; mathematically, the instanton contributions are related to Gromov-Witten and Donaldson-Thomas curve counting invariants, which in this context have natural higher-rank generalisations in the Coulomb branch of the gauge theory. We discuss some of the integrability properties of the resulting partition functions, including a novel reformulation as an infinite rank unitary matrix model. We define a stacky version of the gauge theory whose instanton solutions compute noncommutative Donaldson-Thomas invariants for abelian orbifold singularities. We also discuss how N=4 supersymmetric Yang-Mills theory in four dimensions is analogously related to curve counting on toric surfaces
BSM 2nd March 2012
15:00 to 16:00
Generalized structures of ten-dimensional supersymmetric solutions
Four-dimensional supersymmetric type II string theory vacua can be described elegantly in terms of pure spinors on the generalized tangent bundle T+T. This leads to constraints on M6 involving Hitchin's "generalized complex geometry". In this talk, we apply the same techniques to any ten-dimensional supersymmetric solution, not necessarily factorized as AdS4xM6 or Mink4xM6. I will describe a system of differential equations in terms of forms describing a âgeneralized ISpin(7) structureâ is equivalent to unbroken supersymmetry, in both IIA and IIB. One of the equations in the system reproduces in one fell swoop all the pure spinors equations for four-dimensional vacua.
BSM 6th March 2012
11:30 to 12:30
Y Matsuo A Non-Abelian Self-Dual Gauge Theory in 5+1 Dimensions
We construct a non-Abelian gauge theory of chiral 2-forms (self-dual gauge fields) in 6 dimensions with a spatial direction compactified on a circle of radius R. It has the following two properties. (1) It reduces to the Yang-Mills theory in 5 dimensions for small R. (2) It is equivalent to the Lorentz-invariant theory of Abelian chiral 2-forms when the gauge group is Abelian. Previous no-go theorems prohibiting non-Abelian deformations of the chiral 2-form gauge theory are circumvented by introducing nonlocality along the compactified dimension.
BSM 6th March 2012
14:00 to 15:00
V Balasubramanian Momentum space entanglement and renormalization in quantum field theory
The degrees of freedom of any interacting quantum field theory are entangled in momentum space. Thus, in the vacuum state, the infrared degrees of freedom are described by a density matrix with an entanglement entropy. We derive a relation between this density matrix and a Wilsonian effective action. We argue that the entanglement entropy of and mutual information between subsets of field theoretic degrees of freedom at different momentum scales are natural observables in quantum field theory and demonstrate how to compute these in perturbation theory. The results may be understood heuristically based on the scale-dependence of the coupling strength and number of degrees of freedom. We measure the rate at which entanglement between degrees of freedom declines as their scales separate and suggest that this decay is related to the property of decoupling in quantum field theory.
BSM 7th March 2012
16:00 to 17:00
A geometry of non-geometric fluxes
Starting from double field theory I explain a natural geometric framework in order to describe the so-called non-geometric Q and R fluxes.
BSM 8th March 2012
11:30 to 12:30
AdS4/CFT3 and Quasi-localization of Gravity
I will present and analyze the holographic duals of the N=4 3D superconformal theories of Gaiotto-Witten. I will also discuss the relevance of these backgrounds to the question of quasi-localized gravity in string theory.
BSM 8th March 2012
14:30 to 15:30
Searching for U-duality supermultiplets
BSM 13th March 2012
11:30 to 12:30
Amplitudes for Fivebranes
Co-authors: Darren Smyth (UBC), Evgeny Sorkin (UBC), Jared Stang (UBC)

We study the complexified three point amplitudes, the basic building blocks for helicity amplitudes, for various six dimensional supersymmetric theories. In particular, we construct the amplitudes for the (2,0) theory, the worldvolume theory on coincident fivebranes in M theory, and discuss the implications for the dynamics of these mysterious theories.
BSM 13th March 2012
14:00 to 15:00
A Kleinschmidt Infinite discrete symmetries near singularities and modular forms
When approaching a spacelike singularity the BKL conjecture states that the classical relativity dynamics are governed by chaotic oscillations. These can be alternatively described using a so-called cosmological billiard. When quantising this system one is led to automorphic forms of hyperbolic Weyl groups. The construction of some of these automorphic forms can be phrased conveniently using division algebras. If time permits some features of other Eisenstein series will also be discussed.
BSM 14th March 2012
14:00 to 15:00
B de Wit The 4D/5D connection, black holes and higher-derivative couplings
In this talk we review the known higher-derivative couplings in supergravity with eight supercharges in 4 and 5 space-time dimensions. These couplings play an important role in deriving the sub-leading corrections to BPS black hole entropy. It is demonstrated how an off-shell 4D/5D connection clarifies previous results and leads to new insights.
BSM 14th March 2012
18:30 to 19:30
String Theory, Duality and Art
String theory is at the cutting edge of theoretical physics. Its deep goal is to unify the conflicting paradigms of quantum mechanics and relativity. In doing so, string theory brings up new ways of seeing the world, with hidden dimensions and novel surprising symmetries and relationships. This event will begin with an accessible introduction to string theory by David Berman followed by a presentation and discussion with Grenville Davey on his art and how aspects of string theory and contemporary physics have been an inspiration. A wine reception will follow.
BSM 15th March 2012
11:30 to 12:30
F Passerini A review of localisation, moving to localisation in 5d theories (Journal Club)
BSM 20th March 2012
11:30 to 12:30
D Jafferis Supersymmetric sphere partition functions in three dimensions
BSM 20th March 2012
14:00 to 15:00
Chern-Simons Vector Models
Lines of large-N conformal fixed points with and without supersymmetry are plentiful in three dimensions, thanks in part to the quantization of the Chern-Simons level k. Such theories are interesting for a variety of reasons, most importantly for their potential role as holographic dual descriptions of quantum theories of gravity in AdS4. In this talk, we will study a particularly simple and instructive non-supersymmetric example -- U(N) Chern-Simons theory coupled to fundamental fermions. As we shall illustrate by calculating the free energy of the theory on R2 at finite temperature for all values of the 't Hooft coupling lambda=N/k, this theory turns out to be surprisingly tractable in the large-N limit.
BSM 21st March 2012
16:00 to 17:00
Holographic description of boundary and interface CFTs
We review the construction of supergravity solutions in six dimensional supergravity which are preserve half the super symmetries of the AdS3 x S3 vacuum and give a realization of 2 dimensional interface CFTs of the Janus type. By relaxing the regularity conditions we enlarge the space of solutions to include two new half-BPS configurations, which we refer to as the cap and funnel. We present evidence that solutions which include caps can be used to give a holographic realization of boundary CFTs.
BSM 22nd March 2012
11:30 to 12:30
J Sparks Gravity duals of supersymmetric gauge theories on curved manifolds
It has recently been shown that one can define three-dimensional N=2 supersymmetric gauge theories on compact curved manifolds (certain squashed spheres and Lens spaces). Moreover, the expectation value of any BPS operator in such a theory localizes, reducing the path integral to a finite dimensional matrix integral. I will explain how to construct gravity duals to a large class of such theories, which have a large N limit. The gravitational free energy is shown to precisely match the corresponding field theory free energy, as a function of geometric parameters in the large N limit.
BSM 22nd March 2012
14:00 to 15:00
E Bergshoeff New Results on Massive Gravity
We first review the general features underlying the construction of the 3D New Massive Gravity theory. Next, we show in which sense, at least at the linearized level, this theory can be extended to higher dimensions. An important role is played by exotic representations of massive spin 2. The prospect for interactions is discussed
BSM 27th March 2012
11:30 to 12:30
Branes and wrapping rules
In this talk we discuss the complete classification of half-supersymmetric branes in toroidally compactified IIA/IIB string theory in terms of representations of the T-duality group. We show that the branes of ten-dimensional IIA/IIB string theory must satisfy, upon toroidal compactification, specific wrapping rules in order to reproduce the number of supersymmetric branes in lower dimensions. The realisation of these wrapping rules suggests that IIA/IIB string theory contains a whole class of generalised Kaluza-Klein monopoles. We find examples of T-duality representations of branes in lower dimensions, suggested by supergravity, of which none of the component branes follow from the reduction of any brane in ten-dimensional IIA/IIB string theory.
BSM 27th March 2012
14:00 to 15:00
A Basu Supersymmetry constraints on the R^4 multiplet in type IIB on T^2
I shall talk about a class eight derivative interactions in the effective action of type IIB string theory compactified on T^2. These 1/2 BPS interactions have moduli dependent couplings. I shall impose the constraints of supersymmetry to show that each of these couplings satisfy a first order differential equation on moduli space which relate it to other couplings in the same supermuliplet. The couplings which only depend on the SO(2)\SL(2,R) moduli satisfy Laplace equation on moduli space. On the other hand, the ones which only depend on the SO(3)\SL(3,R) moduli are far more complicated, and satisfy Poisson equation on moduli space, where the source terms are given by other couplings in the same supermultiplet.
BSM 28th March 2012
16:00 to 17:00
F Benini M2-branes at toric Calabi-Yau 4-fold singularities
The low energy dynamics of M2-branes at a CY4 singularity, possibly with torsion flux, is a 3d N=2 superconformal theory. I will describe a type IIA reduction that allows, in some cases, to read off from D-branes a field theory description, as a Chern-Simons-matter quiver gauge theory with flavors and unequal ranks. I will also discuss how to compute the quantum moduli space of these theories.
BSM 29th March 2012
11:30 to 12:30
Uplifting the vacuum in Heterotic M theory
This talk includes some general remarks about formulating supergravity theories on manifolds with boundary, and addresses the specific problem of moduli stabilisation with a vanishing cosmological constant in Heterotic M theory.
BSM 29th March 2012
14:00 to 15:00
Zero-energy states in supermembrane matrix models
We review recent progress concerning the mathematical problem of determining existence, uniqueness, and structure of zero-energy states in supermembrane matrix models, relevant for the quantum mechanical description of relativistic membranes, reduced Yang-Mills theory, and M-theory. Different approaches to this problem involve octonionic deformations, averaging of simpler subsystems, as well as a well-defined Witten index counting the number of weakly decaying zero-energy states.
BSM 30th March 2012
16:00 to 17:00
Nonabelian action of M5-branes
I will talk about a recent construction for an action for non-abelian 2-form in 6-dimensions. The action consists of a non-abelian generalization of the abelian action of Perry and Schwarz for a single M5-brane. It admits a self-duality equation on the field strength as the equation of motion. It has a modified 6d Lorentz symmetry. On dimensional reduction on a circle, our action gives the standard 5d Yang-Mills action. Based on these properties, we propose that our theory describes a theory of multiple M5-branes in flat space.
BSMW02 2nd April 2012
14:00 to 15:30
M Spradlin A Practical Guide to Scattering Amplitudes: Previously Impossible Calculations Made Trivial
The past several years have seen dramatic progress in our understanding of scattering amplitudes, particularly in supersymmetric gauge and gravity theories. Theoretical advances including the discovery of rich mathematical structure and hidden symmetries have led also to practical advances which in many cases render previously impossible field theory calculations trivial. I will review these and recent related developments on correlation functions and Wilson loops in supersymmetric Yang-Mills theory.
BSMW02 2nd April 2012
16:00 to 17:30
The quark anti-quark potential and the generalized cusp anomalous dimension at any coupling
BSMW02 3rd April 2012
09:00 to 10:30
Scattering Amplitudes in Three Dimensions
A great deal of progress has been made in computing scattering amplitudes in 4d quantum field theories by expressing the amplitudes in terms of variables known as twistors. In this talk, I will describe twistorial methods for computing scattering amplitudes in 3d quantum field theories, in particular superconformal Chern-Simons theories and supersymmetric Yang-Mills theories. These methods have led to the discovery of new symmetries and dualities in 3d quantum field theories.
BSMW02 3rd April 2012
11:00 to 12:30
Taming amplitudes and correlation functions in N=4 SYM
BSMW02 3rd April 2012
14:00 to 15:30
L Mason Amplitudes and Wilson loops in twistor space
Amplitudes and correlation functions have rich geometric structure in twistor space. In this talk I will explain how how maximally supersymmetric Yang Mills amplitudes and Wilson loops can be computed in twistor space and how their duality can be demonstrated at the level of the loop integrand. If there is enough time, I will discuss recent progress with gravity ampltiudes.
BSMW02 3rd April 2012
16:00 to 17:30
Harmony of color and kinematics - from trees to loops
Only a few years old, the idea that kinematic building blocks of scattering amplitudes have the same structure and properties as the Lie-algebra color factors - known as color-kinematics duality - has proven quite fruitful. Although the origins of the kinematic Lie-algebra structure remains unknown, it has improved our understanding of non-planar gauge theory and gravity. In this talk, I will review the status of color-kinematics duality at tree and loop level, illuminating the open problems as well as the techniques for calculating non-planar Yang-Mills and gravity loop amplitudes.
BSMW02 4th April 2012
09:00 to 10:30
From Orthogonal Grassmanian to Three-algebra
The leading singularities of ABJM amplitudes are given by the residues of an Orthogonal Grassmanian. I will discuss how this information controls the multi-loop amplitude, revealing an interesting relation between 4D N=4 SYM and ABJM. The behavior of the residues under complex deformation encodes, to the first order, the recent kinematic/three-algebra duality.
BSMW02 4th April 2012
11:00 to 12:30
Amplitudes and Wilson loops in N=4 SYM in special kinematics
BSMW02 4th April 2012
14:00 to 15:30
Mathematical structures of scattering amplitudes
BSMW02 4th April 2012
16:00 to 17:30
Symbols and Bootstraps for scattering amplitudes
I will describe the application of a bootstrap program for scattering amplitudes based on analytic constraints from the operator product expansion for light-like Wilson loops and multi-Regge limits. Together with an ansatz for the space of relevant functions these place powerful constraints on the form of multi-loop amplitudes.
BSM 5th April 2012
11:30 to 12:30
T Takimi Studies of the Nambu-brancket M5-brane theory
BSM 5th April 2012
16:00 to 17:00
Superstring perturbation theory revisited - a special Teleconference seminar
BSM 10th April 2012
14:00 to 15:00
(2,0) theory on (singular) circle fibrations
Compactification of six-dimensional (2,0) superconformal theory on a circle has five-dimensional maximally supersymmetric Yang-Mills theory as its low-energy effective theory. We describe the generalization to six-manifolds that are circle fibrations. A further generalization is to allow certain kinds of singularities where the fibre radius shrinks to zero.
BSM 10th April 2012
16:00 to 17:00
S Bolognesi N^3 and Junctions in 6D (2,0) Theories
We discuss the string junctions in the Coulomb phase of 6 dimensional superconformal (2,0) theories as candidates for the N^3 degrees of freedom of the fundamental theory.
BSM 11th April 2012
11:30 to 12:30
Superconformal models in six dimensions
I review the recent construction of six-dimensional (1,0) superconformal models with non-abelian gauge couplings for multiple tensor multiplets. A crucial ingredient in the construction is the introduction of higher-rank tensor fields. I discuss various examples and the possible relation to the (2,0) theories underlying the dynamics of multiple M5 branes.
BSM 12th April 2012
14:00 to 15:00
H Singh Uplifting 5D SYM to 6D and M5-branes
BSM 12th April 2012
16:00 to 17:00
M Wolf Contact instantons and twistor geometry
Subject of this talk is the twistor geometry discussion of a five-dimensional generalisation of the instanton equation known as the contact instanton equation. This equation was recently introduced in the context of (twisted) supersymmetric Yang-Mills theory on the five-dimensional sphere. If time permits, certain extensions to higher dimensions and supersymmetric generalisations will also be presented.
BSM 13th April 2012
09:30 to 10:15
The correlator of four stress-tensor multiplets in N=4 SYM: Part 1. (Talk to be held in Potter Room, Pavilion B, CMS)
Joint conference day organised with DAMTP, University of Cambridge
BSM 13th April 2012
10:15 to 11:00
Vanishing superconformal indices and chiral symmetry breaking. (Talk to be held in Potter Room, Pavilion B, CMS)
Joint conference day organised with DAMTP, University of Cambridge
BSM 13th April 2012
11:30 to 12:15
The correlator of four stress-tensor multiplets in N=4 SYM: Part 2. (Talk to be held in Potter Room, Pavilion B, CMS)
Joint conference day organised with DAMTP, University of Cambridge
BSM 13th April 2012
12:15 to 13:00
Conformal Regge theory. (Talk to be held in Potter Room, Pavilion B, CMS)
BSM 13th April 2012
14:00 to 14:45
Bootstrapping the N=2 superconformal index. (Talk to be held in Potter Room, Pavilion B, CMS)
Joint conference day organised with DAMTP, University of Cambridge
BSM 13th April 2012
14:45 to 15:30
Higher spins, strings and holography. (Talk to be held in Potter Room, Pavilion B, CMS)
Joint conference day organised with DAMTP, University of Cambridge
BSM 13th April 2012
16:00 to 16:45
V Spiridonov Elliptic hypergeometric integrals and superconformal indices. (Talk to be held in Potter Room, Pavilion B, CMS)
Joint conference day organised with DAMTP, University of Cambridge
BSM 13th April 2012
16:45 to 17:30
Conformal partial waves. (Talk to be held in Potter Room, Pavilion B, CMS)
Joint conference day organised with DAMTP, University of Cambridge
BSMW03 16th April 2012
11:00 to 12:30
Towards Physical Applications of Holographic Duality I
BSMW03 16th April 2012
14:00 to 15:30
Quantum Matter I
BSMW03 16th April 2012
16:00 to 17:30
Towards Physical Applications of Holographic Duality II
BSMW03 17th April 2012
09:00 to 10:30
Towards Physical Applications of Holographic Duality III
BSMW03 17th April 2012
11:00 to 12:30
Quantum Matter II
BSMW03 17th April 2012
14:00 to 15:30
Fluid Dynamics and Gravity I
BSMW03 17th April 2012
16:00 to 17:30
Gong Show
BSMW03 18th April 2012
09:00 to 10:30
Fluid Dynamics and Gravity II
BSMW03 18th April 2012
11:00 to 12:30
Quantum Matter III
BSMW03 18th April 2012
14:00 to 15:30
The View from Experiment
BSMW03 18th April 2012
16:00 to 17:30
Quantum Matter IV
BSMW03 19th April 2012
09:00 to 10:30
Fluid Dynamics and Gravity III
BSMW03 19th April 2012
11:00 to 12:30
Topological phases: basic notions and field-theoretic approaches I
BSMW03 19th April 2012
14:00 to 15:30
Phases of holographic matter I
BSMW03 19th April 2012
16:00 to 17:30
Topological phases: basic notions and field-theoretic approaches II
BSMW03 20th April 2012
09:00 to 10:30
Phases of holographic matter II
BSMW03 20th April 2012
11:00 to 12:30
Topological phases: basic notions and field-theoretic approaches III
BSMW03 20th April 2012
14:00 to 15:30
Fluid Dynamics and Gravity IV
BSMW03 20th April 2012
16:00 to 17:30
Phases of holographic matter III
BSM 24th April 2012
11:30 to 12:30
A CFT dual of General Black Holes
BSM 25th April 2012
11:30 to 12:30
The Holographic Nucleus
BSM 25th April 2012
16:00 to 17:00
The conformal anomaly of M5 branes
BSM 26th April 2012
11:30 to 12:30
BLG model and M5-branes
BSM 26th April 2012
14:00 to 15:00
Double Field Theory and Duality
BSM 30th April 2012
11:30 to 12:30
5d Superconformal Index with Enhanced E-type Global Symmetry
We have recently calculated the superconformal index on 5d N=1 supersymmetric theory with SU(2) gauge group and N fundamental hypermultiplets in the conformal limit where the gauge coupling goes to infinite. This index shows as expected that the global symmetry in the conformal limit is enhanced from the flavor SO(2N) symmetry and the global U(1) symmetry for the instanton number to the exceptional group E(N+1).
BSM 30th April 2012
14:00 to 15:00
J Bhattacharya Soliton stars as holographic confined Fermi liquids
We shall report on a holographic dual of a confined Fermi liquid state which is constructed by putting a charged fluid of fermions in the AdS soliton geometry. We shall compare these solition star solutions with other existing zero temperature solutions and find interesting phase transitions in certain regions of parameter space. We will also analyze the probe fermion equations (in the WKB approximation) in the background of this soliton star geometry to confirm the presence of many sharp Fermi-surfaces in the system.
BSM 1st May 2012
11:30 to 12:30
Solipsism in the dS static patch
I will discuss correlation functions in the worldline of an observer in the static patch of dS space. I will show how an emergent conformal structure appears that points towards a holographic dual in terms of a conformal quantum mechanics. Furthermore I'll make contact with the better studied dS/CFT picture by analyzing the spectrum of quasi-normal modes.
BSM 2nd May 2012
11:30 to 12:30
Homogeneous M2 duals
I will summarise the search for candidate dual geometries to 3-dimensional N-extended superconformal field theories, with N>4. This includes a classification of eleven-dimensional homogeneous lorentzian manifolds with a transitive isometric action of SO(3,2) x SO(N). We find no (new) backgrounds with N>5, but several new (to us) backgrounds with N=5, at least one of which is supersymmetric. We consider both AdS and non-AdS backgrounds. This is work in progress with Mara Ungureanu.
BSM 3rd May 2012
13:00 to 14:00
A Strominger Progress in dS/CFT
BSM 8th May 2012
11:30 to 12:30
R Gopakumar Triality in Minimal Model Holography
BSM 9th May 2012
11:30 to 12:30
Engineering Holographic Graphene
The AdS/CFT correspondence of string theory offers the hope of direct, mathematically precise and systematically correctable study of strongly coupled quantum systems. Progress toward this goal will be described in the context of a simple example: the probe D-brane dual of a class of relativistic field theories which resemble the description of graphene by relativistic fermions. A hypothesis that graphene can be such a strongly correlated quantum fluid and at the same time exhibit behaviours which are well modeled by non-interacting relativistic fermions will be discussed as well as some interesting new phases of matter which are suggested by the D-brane construction.
BSM 9th May 2012
16:00 to 17:00
M Rangamani The Dirichlet problem in AdS and beyond
BSM 10th May 2012
14:00 to 15:00
D Rodriguez-Gomez 5d gauge theories and AdS/CFT
BSM 14th May 2012
14:00 to 15:00
S Wadia Solving Chern-Simons theory with vector matter in the large N limit
We describe a method for solving Chern-Simons theory on R_2x S^1 with fermionic and bosonic matter in the large N limit. We also discuss an infinite set of partially conserved currents in these theories.
BSM 15th May 2012
11:30 to 12:30
Spatially modulated phases in AdS/CFT
BSM 16th May 2012
11:30 to 12:30
S Ramgoolam Counting and construction of D-brane quantum states in AdS/CFT
BSM 17th May 2012
14:00 to 15:00
Cusp anomalous dimension in N=4 super Yang-Mills from integrability
BSM 22nd May 2012
11:00 to 12:00
Superconformal field theories in 6D with non-abelian tensor-Yang-Mills couplings
I will describe a class of N=(1,0) superconformal field theories in six dimensions involving the couplings of tensor multiplets to Yang-Mills multiplet in a tensor hierarchy framework in which there is an intricate group structure and the tensor multiplets transform in nontrivial representations of the gauge group. These models were constructed in 1108.4060 and developed further in 1204.0542.
BSM 23rd May 2012
11:30 to 12:30
D Tong Optical Conductivity from a Holographic Lattice
BSM 24th May 2012
11:30 to 12:30
CFT probes of bulk geometry
BSM 24th May 2012
14:00 to 15:00
Generalised Geometry for non-relativistic backgrounds
BSM 25th May 2012
11:30 to 12:30
AdS and Lifshitz Black Holes in Conformal and Einstein-Weyl Gravity
BSMW04 28th May 2012
10:15 to 11:00
F Denef String glasses and beyond
I will review some recent work on complex, glassy systems in string theory and cosmology.
BSMW04 28th May 2012
11:30 to 12:15
Microstate Geometries - what do they tell us about Black Holes?
Black hole microstate geometries exist in the same regime of parameters as a large classical black hole, but have no horizon. One can construct incredibly-large families of such geometries, and argue that they have the right properties to describe some of the typical microstates of the black hole. I will review the construction and properties of microstate solutions for supersymmetric, extremal non-supersymmetric and nonextremal black holes, and discuss what they teach us about black hole physics.
BSMW04 28th May 2012
12:15 to 13:00
Lifshitz as a deformation of AdS
BSMW04 28th May 2012
14:00 to 14:45
S Murthy Some progress in computing exact black hole entropy using localization
I will report on some recent progress in computing the exact quantum entropy of supersymmetric black holes using localization techniques. After a brief review of recent developments, I will present new results on the derivation of the full solution manifold of the localization equations in N=2 supergravity. I will then discuss some clues that are emerging about the (ir)relevance of (non) F-terms to the quantum black hole entropy.
BSMW04 28th May 2012
14:45 to 15:30
J Manschot D-branes on elliptic Calabi-Yau manifolds
I'll discuss the quantum geometry of elliptically fibered Calabi-Yau threefolds. A holomorphic anomaly equation for the topological string free energy is proposed, which is iterative in the genus expansion as well as in the curve classes in the base. T-duality on the fibre implies that the topological string free energy also captures the BPS-invariants of D4-branes wrapping the elliptic fibre and a class in the base. We verify this proposal by explicit computation of the BPS invariants of 3 D4-branes on the rational elliptic surface.
BSMW04 28th May 2012
16:00 to 16:45
S Ross Holography for asymptotically locally Lifshitz spacetimes
I will review the holographic description of field theories with an anisotropic scaling symmetry. I will explain how to define general boundary data for this correspondence, and discuss the asymptotic expansion (the analogue of the Fefferman-Graham expansion) and the holographic renormalization for general boundary data. At the end of the talk, I will describe work in progress on alternative boundary conditions.
BSMW04 28th May 2012
16:45 to 17:30
Un-twisting the NHEK with spectral flows
Schroedinger spacetimes geometrically realize the nonrelativistic conformal group, reason for which they have been proposed as holographic duals to strongly coupled non-relativistic CFTs. On the other hand, it has been recently shown that black holes in three-dimensional Schroedinger spacetimes exhibit a previously unknown Virasoro asymptotic symmetry, which is indicative of a full conformal symmetry. To uncover it, I will construct a Fefferman-Graham-like expansion for the relevant modes in asymptotically three-dimensional Schroedinger spacetimes by mapping them to an auxiliary AdS(3) spacetime, and show that the renormalized on-shell action for these modes is identical to the one for the gravity modes in the auxiliary AdS(3). The holographic stress-energy tensor one obtains by this procedure is symmetric, conserved and its trace yields the same conformal anomaly as in AdS(3).
BSMW04 29th May 2012
09:30 to 10:15
Bianchi Attractors: A Classification of Extremal Black Brane Geometries
Extremal black branes are of interest because they correspond to the ground states of field theories at finite charge density in gauge/gravity duality. The geometry of such a brane need not be translationally invariant in the spatial directions along which it extends. A less restrictive requirement is that of homogeneity, which still allows points along the spatial directions to be related to each other by symmetries. In the talk we will discuss new classes of homogeneous but anisotropic extremal black brane horizons, which could naturally arise in gauge/gravity dual pairs. In 4+1 dimensional spacetime, we will show that such homogeneous black brane solutions are classified by the Bianchi classification, which is well known in the study of cosmology, and fall into nine classes.
BSMW04 29th May 2012
10:15 to 11:00
Black hole monodromy
In this talk we will revisit the computation of greybody factors using a novel set of tools based on the monodromy technique. Our aim is to emphasize that the analytic properties of the black hole background play a crucial role in the scattering problem. In particular, acknowledging the existence of the inner horizon allows for exact expressions of the transmission and reflection coefficients without taking any low or high frequency approximation. More interestingly, this approach sheds light on the CFT interpretation of the B-H entropy as a Cardy formula for a large class of black holes in 4D and 5D.
BSMW04 29th May 2012
11:30 to 12:15
Supersymmetric field theories on curved manifolds and holography
I will discuss certain aspects of supersymmetric gauge theories on curved manifolds and how these interplay with holography in supersymmetric asympotically locally AdS geometries. In particular, I will present proposals for gravity duals of field theories on different squashed three-spheres.
BSMW04 29th May 2012
12:15 to 13:00
J Hartong Lifshitz Holographic Renormalization from AdS
Lifshitz space-times with critical exponent z=2 can obtained by dimensional reduction of Schroedinger space-times with critical exponent z=0. The latter space-times are asymptotically AdS solutions of AdS gravity coupled to an axion-dilaton system (or even just a massless scalar field). This basic observation is used to perform holographic renormalization for 4-dimensional asymptotically locally Lifshitz space-times by dimensional reduction of the corresponding problem of holographic renormalization for 5-dimensional asymptotically AdS space-times coupled to an axion-dilaton system. In this setup the 4-dimensional structure of the Lifshitz Fefferman-Graham expansion and the structure of the counterterm action, including the scale anomaly, will be discussed.
BSMW04 29th May 2012
14:00 to 14:45
T Takayanagi Holographic Dual of BCFT
We propose a holographic dual of a conformal field theory defined on a manifold with boundaries, i.e. boundary conformal field theory (BCFT). This new holography successfully calculates the boundary entropy or g-function in two dimensional BCFTs and it agrees with the finite part of the holographic entanglement entropy. Moreover, we can naturally derive a holographic g-theorem. We conjecture a higher dimensional analogue of g-theorem and give some evidences from both the gravity and field theory side. We also discuss the gravity dual with boundaries with arbitrary shape.
BSMW04 29th May 2012
14:45 to 15:30
S El-Showk The Resurgent Bootstrap and the 3D Ising Model
In recent years the conformal bootstrap has emerged as a surprisingly powerful tool to study CFTs in dimensions greater than two. In this talk I will explain how crossing symmetry of the four-point function of scalar operators can be used to extract very non-trivial constraints on the spectrum of a putative CFT in arbitrary spacetime dimension. Applying these techniques in D=3 we will find that the 3D Ising model lies at a special point in the space of CFTs. Moreover, we will show that constraints from conformal invariance can be used to significantly reduce the error in the known estimates for the dimensions of operators and suggest a method to generalize this to a compute the dimensions of all operators in the theory. Time permitting, I will mention some more general applications of this technology, including holography.
BSMW04 29th May 2012
15:45 to 16:30
Octonionic black holes
I will display the generalisation of solutions describing bound states of interacting non-BPS extremal black holes to N=8 supergravity. I will explain in particular how gravitini N=2 multiplets vector fields and some hyper-multiplets scalars are involved in a non-trivial manner in these solutions. For this purpose I will define `special coordinates' for the N=8 moduli which generalise naturally the special Kaehler coordinates. Then I will display some physical properties of these solutions, and in particular the existence of three by three interactions that are absent in the BPS solutions, and which are responsible for an extra contribution to the ADM angular momentum.
BSMW04 29th May 2012
16:30 to 17:15
Massive and higher spin string scattering off D-brane bound-states
We study scattering amplitudes of higher spin closed-string states off D-brane bound-states. For states in the first Regge trajectory we find remarkable simplifications both at tree level and at one loop. We discuss the high energy behavior in the Regge limit and comment on the validity of the eikonal approximation in this regime.
BSMW04 30th May 2012
09:30 to 10:15
A Strominger Progress in dS/CFT
BSMW04 30th May 2012
10:15 to 11:00
G Dall'agata Flow equations for Black Holes in (gauged) supergravity
We review the fake superpotential formalism for describing extremal black holes and discuss its possible extensions to the case of black holes in asymptotically AdS spacetimes.
BSMW04 30th May 2012
11:30 to 12:15
Black holes spitting out supertubes
We search for stable bound states of non-extremal rotating three-charge black holes in five dimensions (Cvetic-Youm black holes) and supertubes. We do this by studying the potential of supertube probes in the non-extremal black hole background and find that generically the marginally bound state of the supersymmetric limit becomes metastable and disappears with non-extremality (higher temperature). However near extremality there is a range of parameters allowing for stable bound states, which have lower energy than the supertube-black hole merger. Angular momentum is crucial for this effect. We use this setup in the D1-D5 decoupling limit to map a thermodynamic instability of the CFT (a new phase which is entropically dominant over the black hole phase) to a tunneling instability of the black hole towards the supertube-black hole bound state. This generalizes the results of "Moulting Black Holes", which mapped an entropy enigma in the bulk to the dual CFT in a supersymmetric setup.
BSMW04 30th May 2012
12:15 to 13:00
Systematics of supersymmetric flows along the conifold
Working in N=4 gauged supergravity, we analyze the conditions for five-dimensional supersymmetric domain walls, which correspond to holographic RG flows. Applying our results to a class of consistent truncations of string theory, we obtain a general flow for SCFT deformations, as well as a new flow closely related to the resolved conifold. We also discuss a superpotential for the baryonic branch of the Klebanov-Strassler solution.
BSMW04 30th May 2012
13:00 to 13:45
Some thoughts on black hole microstates
BSMW04 31st May 2012
09:30 to 10:15
B de Wit Deformations of special geometry; in search of the topological string
The possible relation between the effective action for N=2 supergravity with couplings proportional to the square of the Weyl tensor and the topological string partition function is explored. A number of systematic features is extracted with particular attention to the presence of non-holomorphic corrections.
BSMW04 31st May 2012
10:15 to 11:00
Brane and black hole supergravity horizons
Insights into the physics of gauge theories and strings have been gained by looking into the properties of the horizons of brane and black hole supergravity solutions. In this talk, I shall present a systematic exploration of the topology and geometry of such horizons utilizing the recent progress that has been made in the classification of supergravity backgrounds. The focus will be in heterotic, type II and M-horizons.
BSMW04 31st May 2012
11:30 to 12:15
Conformal Symmetry for General Black Holes
The boundary conditions of general black holes in asymptotically flat spacetimes can be modified such that a conformal symmetry emerges. The black holes with asymptotic geometry modified in this manner satisfy the equations of motion of minimal supergravity in one dimension more. Their symmetry suggests that a dual conformal field theory description exists that can account for the black hole entropy even in the case of black holes that are far from extremality.
BSMW04 31st May 2012
12:15 to 13:00
Subtracted Geometry From Harrison Transformations
We consider general four dimensional black holes in string theory and show that their subtracted geometry - which makes the hidden conformal symmetry manifest - can be obtained by applying Harrison transformations on the black holes.
BSMW04 31st May 2012
14:00 to 14:45
Constructing generic non-extremal black-hole solutions of N=2, d=4,5 supergravities
I will review the general construction of non-extremal black-hole and black-brane solutions of N=2,d=4 and d=5 supergravity coupled to vector multiplets, and their properties. I will describe the explicit solutions of a few models, their extremal (supersymmetric and non-supersymmetric) limits, entropies, non-extremality functions etc. and a formalism that simplifies dramatically the search and construction of those solutions.
BSMW04 31st May 2012
14:45 to 15:30
A Bagchi Flat Space Holography as a limit of AdS/CFT
We construct flat-space holography as a limit of usual AdS/CFT concentrating on the 3d bulk/2d boundary example. The asymptotic group of symmetries at null infinity of flat spacetimes is the infinite dimensional Bondi-Metzner-Sachs (BMS) group. We show how this emerges in the flat-space limit of AdS symmetries. The flat limit also induces a contraction on the CFT which in 2d reduces to the Galilean Conformal Algebra (GCA), studied previously in the context of non-relativistic systems. Quantum gravity in flat space would be described by the representations of the GCA. We comment on the relevant representations of the GCA and correlation functions. We also mention some intriguing results in ongoing work on the "flat" BTZ.
BSMW04 31st May 2012
16:00 to 16:45
Universal properties and the first law of black hole inner mechanics
Recently, we showed by explicit computations that the product of all the horizon areas is independent of the mass, regardless of the topology of the horizons. The universal character of this relation holds for all known five dimensional asymptotically flat black rings, and for black strings. This gives further evidence for the crucial role that the thermodynamic properties at each horizon play in understanding the entropy at the microscopic level. To this end we proposed a 'first law' for the inner Cauchy horizons of black holes. The validity of this formula, which seems to be universal, was explicitly checked in all cases.
BSMW04 31st May 2012
16:45 to 17:30
S Ramgoolam Branes, permutations and oscillators
The group theory of permutations plays a central role in understanding the emergence of giant graviton branes from gauge-invariant operators in the dual gauge theory. This holds for BPS operators as well as their non-BPS excitations. Young diagrams, Schur-Weyl duality and double cosets are some of the concepts that are useful in analysing the action of the gauge-theory one-loop dilatation operator acting on brane excitations. The analysis leads to harmonic oscillator systems describing strings attached to the branes. The talk will be based primarily on http://arxiv.org/abs/1204.2153.
BSMW04 1st June 2012
09:30 to 10:15
R Emparan Black brane fluid flows
We study how the hydrodynamics of a black brane changes when we enclose it in a finite cylindrical cavity with Dirichlet boundary conditions. For neutral black branes, we see how the Gregory-Laflamme instability switches off and study the critical point where the instability disappears. For black D3 branes, as the cavity radius decreases one obtains the sequence of descriptions "blackfolds > fluid/AdS-gravity > membrane paradigm". We show that, to leading order above extremality, "sound comes from the throat".
BSMW04 1st June 2012
10:15 to 11:00
W Song Comments on dipole theories
Dipole theories are interesting for many reasons. On the one hand, the background is deformed, and therefore is a simple example of non-AdS holography. On the other hand, the bulk spacetime can be obtained by a generalized spectra flow, and therefore many properties are inherited from AdS. Furthermore, dipole/CFT duality is closely related to Kerr/CFT correspondence. By studying dipole theory, we could learn some information about the CFT that is dual to Kerr. In this talk I will comment on dipole/CFT duality, and string sigma models on dipole backgrounds.
BSMW04 1st June 2012
11:30 to 12:15
Black holes, Hilbert-space networks, and quantum information transfer
A unitary resolution of the black hole information problem, or unitarity crisis, appears to require transfer of quantum information from black holes to their surroundings, in conflict with field-theory locality. One can both model and constrain such evolution. A possible general setting for such evolution, capturing some aspects of locality, is in a Hilbert-space network.
BSMW04 1st June 2012
12:15 to 13:00
Black hole instabilities and local Penrose inequalities
Various higher-dimensional black holes have been shown to be unstable by studying linearized gravitational perturbations. This is often very complicated. I shall describe a simpler method for demonstrating instability. The idea is to construct initial data describing a small perturbation of the black hole and which violates an inequality analogous to the 4d Penrose inequality. I will describe recent work applying the method to non-uniform black strings.
BSM 6th June 2012
11:30 to 12:30
M Berg Quantum Orientifold Effective Actions
I will discuss results from arXiv:1112.5156 on string one-loop contributions to the Kahler metric of D-brane moduli (positions and Wilson lines), in toroidal orientifolds with branes at angles, and minimal supersymmetry. Also I will outline some more recent results on similar calculations for closed string moduli.
BSM 7th June 2012
11:30 to 12:30
Yukawa Couplings in F-Theory Compactifications
BSM 12th June 2012
11:30 to 12:30
Fluxbrane Inflation and Moduli Stabilisation
BSM 13th June 2012
11:30 to 12:30
Good things from brane back-reaction
BSM 14th June 2012
11:30 to 12:30
String theory, the Higgs boson, Dark Matter and the LHC
BSM 20th June 2012
11:30 to 12:30
On Transplanckian Excursions in de Sitter Space
BSMW05 25th June 2012
09:35 to 10:10
Phenomenological Targets for String Model Builders
We shall detail points of interest for string model builders coming from recent data, providing some targets that model builders may like to hit. In particular, we shall discuss higgs and supersymmetry searches, and infer some general statements about the spectra and naturalness of models. We shall also mention the t tbar asymmetry from the Tevatron, which disagrees with Standard Model expectations, recent relevant B decay results, Daya bay implications for neutrino masses and mixings and an inferred 130 GeV line in gamma rays coming from our galaxy.
BSMW05 25th June 2012
10:10 to 10:45
Generic String/M theory Predictions for Particle Physics and Dark Matter
Solutions of string/M theory with low energy supersymmetry have moduli fields with masses which are generically of order the mass of the gravitino. This leads to a spectrum of superpartners with squarks and sleptons just beyond the LHC energy scale. Gluinos could however be produced at the LHC and decay with top and bottom rich final states. The mass of the lightest Higgs boson is predicted to be between 122 and 129 GeV. The moduli fields dominate the pre-BBN Universe leading to a non-thermal history which significantly impacts our picture of dark matter, which is predicted to have two components: axions and W-ino like WIMPS. The tentative high energy photon signal in the Fermi-LAT data can be successfully interpreted as the annihilation of these WIMPs into the Z-boson and a photon. Moreover, we demonstrate that this signal is also consistent with an approximately 50% axion component. The axion component implies that experiments like Planck will NOT observe tensor modes in the CMB.
BSMW05 25th June 2012
11:20 to 11:55
K Choi Cosmological moduli problem and double thermal inflation in large volume scenario
BSMW05 25th June 2012
11:55 to 12:30
Open string axions and the flavor problem
I will describe some bottom up models of particle physics inspired by D-brane phenomenology that address aspects of the flavor problem. I will argue that many of these models lead to an axion arising from open string modes that sometimes falls within the allowed axion window. The phenomenology of these axion models can rule out many models of physics beyond the standard model. A satisfactory solution of the flavor problem seems to produce models that deconstruct extra dimensions.
BSMW05 25th June 2012
14:00 to 14:35
Cosmology and Moduli Stabilisation for Chiral Global Models
I will present recent results which try to combine moduli stabilisation and chiral model building both in the geometric regime and at the quiver locus within a fully consistent type IIB string compactification described in terms of toric geometry. I will also briefly discuss some cosmological applications and a new way to get dS vacuua in a manifestly supersymmetric effective action.
BSMW05 25th June 2012
14:35 to 15:10
Looking for the LARGE volume axiverse
An "axiverse" is a generic prediction of string theory, although the axions are typically extremely hard to detect, and sometimes may not actually solve the strong CP problem. I shall discuss how the axiverse is realised in the LARGE volume scenario, including what the axion couplings are, whether they can be detected, how the QCD axion can arise - and also how to build models with an additional axion-like particle that could explain some intriguing astrophysical anomalies.
BSMW05 25th June 2012
15:10 to 15:45
Weakly interacting slim particles in astrophysics, cosmology and the laboratory
Weakly interacting slim particles (WISPs) appear often in extensions of the standard model, string theory in particular. This is the case of pseudo Nambu Goldstone Bosons, stringy axions, moduli, hidden photons, mini-charged particles and a long etc. The strongest bounds on their existence come frequently from cosmology and astrophysics but, in particular cases, laboratory experiments at the low energy, high intensity frontier, are more relevant. In this talk we review the most relevant astro/cosmo arguments and laboratory experiments used to constrain the existence of WISPs, focusing on the most discussed cases of axion-like particles (ALPs) and Hidden Photons. We will also pay attention to the recent anomalies which could be pointing to the existence of WISPs: the anomalous cooling rate of white dwarfs and the transparency of the Universe to gamma-rays. Finally, we will conclude discussing WISPs as testable cold dark matter candidates.
BSMW05 25th June 2012
16:20 to 16:55
D Luest Non-commutative/non-associative geometry and effective actions of non-geometric string backgrounds
BSMW05 25th June 2012
16:55 to 17:30
R Blumenhagen Strings in Non-geometric Backgrounds
We consider closed bosonic string theory with flat background and constant H-flux. Up to linear order in the flux, this is a solution to the string equations of motion and we are able to define a world-sheet conformal field theory framework to compute scattering amplitudes. In the easiest cases of n-point tachyon amplitudes, we use the properties of the Rogers dilogarithm function to speculate about the nature of the product of functions on spacetimes T-dual to the original configuration.
BSMW05 26th June 2012
09:00 to 09:35
S Raby SU(6) orbifold GUT on M4 x RP2 : Gauge - Higgs unification
In a recent paper we constructed an SU(6) N=2 SUSY model in 6 dimensions. We discuss gauge and SUSY breaking via orbifolding and/or Wilson lines. The model has gauge-Higgs unification. We calculate the GUT scale threshold corrections to gauge coupling unification.
BSMW05 26th June 2012
09:35 to 10:10
Supersymmetric unification and R symmetries
After reviewing some virtues and problems of the minimal supersymmetric standard model (MSSM), I will show that, if one demands anomaly freedom and fermion masses, only R symmetries can forbid the supersymmetric Higgs mass term mu. I will then prove that R symmetries are not available in conventional grand unified theories (GUTs) and argue that this prevents natural solutions to the doublet-triplet splitting problem in four dimensions. On the other hand, higher-dimensional GUTs do not suffer from this problem. I will briefly discuss an explicit string-derived model in which the mu and dimension five proton decay problems are solved by an order four discrete R symmetry, and comment on the higher-dimensional origin of this symmetry.
BSMW05 26th June 2012
10:10 to 10:45
P Nilles The Zip Code of Quarks, Leptons and Higgs Bosons
The location of particles in extra dimensions determines the properties of the 4-dimensional low-energy effective action, such as Yukawa couplings and the pattern of supersymmetry breakdown. We analyze these questions in the framework of the heterotic MiniLandscape.
BSMW05 26th June 2012
11:20 to 11:55
B Nelson An Algorithmic Method for Identifying Swiss Cheese Manifolds
We describe an efficient algorithmic test for the Swiss Cheese property in Calabi-Yau threefolds, which is typically considered in the context of moduli stabilization in Large Volume Scenarios of type~IIB flux compactifications of string theory. The algorithm recasts the issue of moduli stabilization at large volume into the language of algebraic geometry, thereby allowing for a large scale computational analysis. Preliminary results of a scan of Calabi-Yau three folds with small Hodge numbers will be presented.
BSMW05 26th June 2012
11:55 to 12:30
Compactified string/M theory prediction of the Higgs boson mass and properties.
BSMW05 26th June 2012
14:00 to 14:15
Non-geometric fluxes in higher dimensions: I
Non-geometric fluxes appear in four-dimensional gauged supergravities through specific terms in the potential. These terms are of phenomenological interest for the matters of moduli stabilization or de Sitter solutions. Unfortunately, their ten-dimensional origin, and their relation to non-geometry, remain unclear. In this talk, I will present recent progress on these questions. Thanks to a field redefinition in ten-dimensional supergravity, one makes the non-geometric Q and R fluxes appear, and additionally restores a standard notion of geometry. A dimensional reduction can then be performed, and the four-dimensional non-geometric terms of the scalar potential are recovered.
BSMW05 26th June 2012
14:00 to 14:15
Y Sumitomo A Stringy Mechanism for A Small Cosmological Constant
We propose a simple stringy mechanism that prefers metastable vacua with a small cosmological constant. We argue the generic probability distribution for the metastable vacua which peaks with a divergent behavior at the zero value of cosmological constant. Then we illustrate this in a model of type IIB string theory, though the suppression in the model is modest.
BSMW05 26th June 2012
14:15 to 14:30
Non-geometric fluxes in higher dimensions: II
It has been shown that non-geometric fluxes appear in ten-dimensional supergravity by performing a field redefinition. Following a similar strategy in double field theory surprisingly allows for a geometric interpretation of these fluxes. More precisely, the Q-flux appears as part of a dual curvature scalar, reminiscent of the geometric flux f. The R-flux turns out to be a tensor and appears in the same way as the usual H-flux does. Solving the strong constraint connects this formalism to the ten-dimensional approach. Furthermore, some recent lifts of four-dimensional gauged supergravity to double field theory can be matched.
BSMW05 26th June 2012
14:15 to 14:30
Accelerating Universes in String Theory via Field Redefinition
We study cosmological solutions in the effective heterotic string theory with \alpha'-correction terms in string frame. It is pointed out that the effective theory has an ambiguity via field redefinition and we analyze generalized effective theories due to this ambiguity. We restrict our analysis to the effective theories which give equations of motion of second order in the derivatives, just as ``Galileon" field theory. This class of effective actions contains two free coupling constants. We find de Sitter solutions as well as the power-law expanding universes in our four-dimensional Einstein frame. The accelerated expanding universes are always the attractors in the present dynamical system.
BSMW05 26th June 2012
14:30 to 14:45
P Smyth Spontaneous Partial Supersymmetry Breaking
I will review some recent work on spontaneous partial supersymmetry breaking in extended supersymmetry. I will first describe the no-go theorems which forbid N=2 to N=1 spontaneous supersymmetry breaking in global and local supersymmetry, before showing how they are circumvented. I will then discuss some new techniques involving the embedding tensor formalism which allow us to study this problem systemically and find the low-energy effective theory in the N=1 vacuum. This leads to interesting insights into spontaneous partial supersymmetry breaking in supergravity and string theory, as well as new results in quaternionic geometry.
BSMW05 26th June 2012
14:30 to 14:45
N-flation and No-boundary measure
In this talk, I will give a brief review on N-flation models. Moreover, I will present the recent work of N-flation with no-boundary condition which is one of several ways to avoid the singularities of our very early Universe. Even though no-boundary measure disfavours the histories of large e-foldings in inflation, we show another way to lift up the probability of inflationary histories without considering any other factors, but with the large number of fields such as N-flation fields.
BSMW05 26th June 2012
15:00 to 15:15
Bianchi identities for non-geometric fluxes from Palatini-Lovelock-Cartan gravity
Flux compactifications are an important building block for obtaining (semi-)realistic string theory vacua. Conventional H- and geometric flux are rather well-understood in this setting, however, non-geometric fluxes are understood to a far lesser degree.

In this talk, it is first reviewed how certain fluxes can be treated as the torsion of a connection, and how gravity theories can be formulated via the Palatini formalism. Next, this formalism is extended to higher orders in the curvature leading to constraints on the fluxes, which are then interpreted as Bianchi identities.
BSMW05 26th June 2012
15:00 to 15:15
De Sitter vacua in type IIB / F-theory by Kahler uplifting
We derive a sufficient condition and present explicit examples based on toric geometry for realizing meta-stable de Sitter vacua with small positive cosmological constant within type IIB string theory / F-theory flux compactifications with spontaneously broken supersymmetry. There are a number of `lamp post' constructions of de Sitter vacua in type IIB string theory and supergravity. We show that one of them -- the method of `K\"ahler uplifting' by F-terms from an interplay between non-perturbative effects and the leading $\alpha'$-correction -- allows for a more general parametric understanding of the existence of de Sitter vacua. The result is a condition on the values of the flux induced superpotential and the topological data of the Calabi-Yau compactification, which guarantees the existence of a meta-stable de Sitter vacuum if met. Our analysis explicitly includes the stabilization of all moduli, i.e. the K\"ahler, dilaton and complex structure modu li, by the interplay of the leading perturbative and non-perturbative effects at parametrically large volume.
BSMW05 26th June 2012
15:15 to 15:30
Heterotic bundles on toric Calabi-Yau manifolds
We undertake a systematic scan of vector bundles over the database of torically generated Calabi-Yau three-folds in the context of heterotic string compactifications. Specifically, we construct positive monad bundles over Calabi-Yau hypersurfaces in toric varieties, with the number of Kahler moduli equal to one, two and three, and extract physically interesting models. We select models which can possibly lead to three families of matter after quotienting by a freely-acting discrete symmetries and including Wilson lines. About 2000 such models on two manifolds are found.
BSMW05 26th June 2012
15:15 to 15:30
Multi-field inflationary trajectories with a fast-turn feature
We study models of multi-field inflation in which the inflationary trajectory contains a strong bending occurring when the observable scales are still inside the Hubble radius. We discuss the impact of such a fast-tirn feature on the dynamics of the inflationary perturbations - and the traces such an event may leave in the power spectrum of curvature perturbations.
BSMW05 26th June 2012
15:30 to 15:45
Bundles over Nearly-Kahler Homogeneous Spaces in Heterotic String Theory with Flux
String compactifications incorporating non-vanishing H-flux have received increased attention over the past decade for their potential relevance to the moduli stabilization problem. Their internal spaces are in general not Kähler and, therefore, not Calabi-Yau. In the heterotic string an important technical problem is to construct gauge bundles on such spaces. I will present a method of how to explicitly construct gauge bundles over homogeneous nearly-Kähler manifolds of dimension six. These bundles solve the heterotic string including first order alpha' corrections and allow for non-vanishing flux. I will also discuss some of the arising implications for model building.

Related Links •http://arxiv.org/abs/1107.3573 - presented results are based on this paper

BSMW05 26th June 2012
15:30 to 15:45
Lifshitz Solutions in String Theory
I will discuss solutions with Lifshitz scaling within string supergravity for an arbitrary scaling parameter z. After showing how to construct exact Lifshitz spacetimes, I will discuss more general solutions, including black holes with Lifshitz asymptotics.
BSMW05 26th June 2012
16:15 to 16:30
Fluxbrane Inflation
Fluxbrane inflation (arXiv:1104.5016) is a recently proposed stringy realisation of D-term hybrid inflation, featuring some appealing phenomenological characteristics. In contrast to other brane inflation models, fluxbrane inflation has a naturally flat inflaton potential at leading order and thus does not rely on strong warping or an extremely anisotropic compact space. Additionally, the scenario contains a mechanism which allows one to avoid the clash with observational bounds due to cosmic string production rather easily. In my talk, I will present the most interesting aspects of the model and, furthermore, discuss recent progress and new challenges regarding moduli stabilisation (in the context of the LARGE volume scenario) as well as the impact of higher-order corrections on the flatness of the inflaton potential.
BSMW05 26th June 2012
16:15 to 16:30
On Asymptotically de Sitter Space: Entropy & Moduli Dynamics
I will discuss what the present state of the universe, as an asymptotically de Sitter space, tells us about the moduli dynamics in the very early universe. This study is inspired by entropy counting and holographic bounds.
BSMW05 26th June 2012
16:30 to 16:45
(New) Borders for Quantum Cosmology
Quantum Cosmology tackles the quantum description of the early universe. It is aimed as an accessible primer that covers the basics, critically discussing ideas and concepts that comprise our current knowledge. The scope for analyzing quantum cosmological models within a supersymmetric framework is pointed.

As much as possible, it summarizes what we know, what we think we know and what we think we do not know on an equal footing. It is focused for ‘young’, inquisitive minds eager to embark on in-depth research in this field. It is hoped to suggest the tools researchers will need to go on their own, pushing them to ask the right questions rather than seek definitive answers.
BSMW05 26th June 2012
16:30 to 16:45
SO(10) Resolutions in F-theory
We discuss SO(10) GUTs in F-theory, starting with the Tate form for a D5 singularity, and resolving. We then look at codimension two and three singularities to get matter and Yukawa couplings.
BSMW05 26th June 2012
16:45 to 17:00
Stringy Origins of Cosmic Structure: The D-brane vector curvaton
I will discuss how the U(1) vector fields that live on the worldvolumes of D-branes in Type IIB string theory may play the role of vector curvatons and hence give rise to distinctive features in the spectrum and bispectrum of the curvature perturbation. I will first consider vector fields on D3-branes in open-string inflation, as a means of illustrating the principle. I will then discuss a D7-brane vector curvaton scenario in closed-string inflation.
BSMW05 26th June 2012
16:45 to 17:00
M Kerstan Fluxed M5-instantons in F-theory
We discuss the partition function of M5-instantons in F-theory, focussing in particular on vertical M5-instantons that describe the uplift of Type IIB E3-instantons. This duality allows us to determine the partition function of the M5-instanton, which is non-trivial to obtain directly in M-theory.
BSMW05 26th June 2012
17:15 to 17:30
Anomalies and Remnant Symmetries in Heterotic Constructions
First I discuss anomalies in heterotic compactifications. I argue that anomalies will generically not be universal, and illustrate this point by an explicit example of a heterotic orbifold blowup. Then, I investigate the origin of discrete (R and non-R) symmetries on smooth Calabi-Yau manifolds via an GLSM approach.
BSMW05 26th June 2012
17:15 to 17:30
P McGuirk Hidden-sector current-current correlators in holographic gauge mediation
I will discuss gravity duals of the gauge mediation of supersymmetry breaking. In particular, I will discuss how the tools of AdS/CFT can be used to calculate certain two-point functions in the hidden sector which, via the formalism of general gauge mediation, can be related to soft terms in the visible sector.
BSMW05 26th June 2012
17:30 to 17:45
Flux Quantization in F-theory and Freed-Witten Anomaly
Using M/F-theory duality, I will relate the quantization of the G-flux in M-theory to the one of the gauge flux on type IIB D7-branes prescribed by Freed-Witten anomaly cancellation. The correspondence is shown for all unitary and symplectic Kodaira singularities, by explicitly constructing appropriate 4-cycles in the M-theory elliptic fourfold, which are able to detect the global anomaly.
BSMW05 26th June 2012
17:30 to 17:45
One-Loop Calculation of the Oblique S Parameter in Higgsless Electroweak Models
If the Higgs boson does not show up soon, we should look for alternative mechanisms of mass generation, satisfying the many experimental constraints which the Standard Model (SM) has successfully fulfilled so far. Following this aim, we present a one-loop calculation of the oblique S parameter within Higgsless models of Electroweak Symmetry Breaking (EWSB) and analyze the phenomenological implications of the available electroweak precision data. By means of an effective Lagrangian we implement the chiral symmetry breaking SU(2)_L x SU(2)_R -> SU(2)_(L+R) with Goldstones, gauge bosons and one multiplet of vector and axial-vector massive resonance states. Using the dispersive representation of Peskin and Takeuchi and imposing the short-distance constraints dictated by the operator product expansion, we obtain S at the next-to-leading order in terms of a few resonance parameters. We have found that, in order to match the experimental determination of the S parameter, the res onance masses are required to be over the TeV scale in this kind of strongly-coupled EWSB scenarios.
BSMW05 26th June 2012
17:45 to 18:00
Moduli Stabilisation of Heterotic String Theory with Flux
I will discuss the next to leading order corrections to the heterotic bundle constructions of Klaput, Lukas and Matti. I will show how these constructions lead to a non-zero H-flux at next to leading order, and how this flux may be used to stabilise either the dilaton, or the volume of the internal space. I will then add a gaugino condensate to the 4D supergravity, and show that for certain bundle choices it is possible to stabilise all moduli at consistent values.
BSMW05 26th June 2012
17:45 to 18:00
V Mehta String--derived models and light U(1) embeddings
Extra U(1) extensions of the Standard Model arising from string theory have been considered in the literature since the mid-80s. Such a U(1) can play an important phenomenological role in solving the \mu problem and suppressing other unwanted operators, such as dimension four and five proton decay mediating operators. Yet keeping the U(1) unbroken down to low scales in quasi-realistic string models turns out to be highly non-trivial. In this talk I will discuss the constraints and some scenarios in which they may be alleviated.
BSMW05 26th June 2012
18:00 to 18:15
D Mehta Numerical Algebraic Geometry: A New Perspective on String and Gauge Theories
BSMW05 27th June 2012
09:00 to 09:35
Searching for de Sitter vacua in String Theory
BSMW05 27th June 2012
09:35 to 10:10
Anti-branes in Klebanov-Strassler: to be or not to be?
Anti-branes in the deformed conifold are used for example to construct de Sitter vacua. In the probe approximation, they lead to a metastable state. I will present work done over the last three years to go beyond the probe approximation by taking into account the back-reaction of the anti-branes. To be, or not to be (a metastable state), that is the question. We are pinning down the answer.
BSMW05 27th June 2012
10:10 to 10:45
The Wasteland of Random Supergravities
We show that in a general N=1 supergravity with N >> 1 scalar fields, an exponentially small fraction of the de Sitter critical points are metastable vacua. Taking the superpotential and Kahler potential to be random functions, we construct a random matrix model for the Hessian matrix, which is well-approximated by the sum of a Wigner matrix and two Wishart matrices. We compute the eigenvalue spectrum analytically from the free convolution of the constituent spectra and find that in typical configurations, a significant fraction of the eigenvalues are negative. Using Coulomb gas techniques, we then determine the probability P of a large fluctuation in which all the eigenvalues become positive. Strong eigenvalue repulsion makes this extremely unlikely: we find P \propto exp(-c N^2), with c a constant, for generic critical points. Our results have significant implications for the counting of de Sitter vacua in string theory, but the number of vacua remains vast.
BSMW05 27th June 2012
11:20 to 11:55
Tensor modes on the string theory landscape
We attempt an estimate for the distribution of the tensor mode fraction $r$ over the landscape of vacua in string theory. The dynamics of eternal inflation and quantum tunneling lead to a kind of democracy on the landscape, providing no bias towards large-field or small-field inflation regardless of the class of measure. The tensor mode fraction then follows the number frequency distributions of inflationary mechanisms of string theory over the landscape. We show that an estimate of the relative number frequencies for small-field vs large-field inflation, while unattainable on the whole landscape, may be within reach as a regional answer for warped Calabi-Yau flux compactifications of type IIB string theory.
BSMW05 27th June 2012
11:55 to 12:30
String mass hierarchies and experimental predictions
BSMW05 27th June 2012
14:00 to 14:35
Calabi-Yau and Non-Calabi-Yau backgrounds for heterotic phenomenology
I will discuss various aspects of model building and moduli stabilization in heterotic string theory. This will include building standard models from pure abelian gauge field configurations, and investigating compactifications on manifolds admitting SU(3) structures with intrinsic torsion.
BSMW05 27th June 2012
14:35 to 15:10
Vector Bundles and Moduli Stabilization in Heterotic Theories
I will discuss recent work on moduli stabilization without Neveu-Schwarz three-form flux in Calabi-Yau compactifications of Heterotic M-theory. In particular, I discuss a systematic approach to stabilizing the complex structure moduli in heterotic vacua and how the holomorphic deformations of the gauge bundle can naturally lead to the consideration of multiple Calabi-Yau threefolds, connected by geometric transitions.
BSMW05 27th June 2012
15:10 to 15:45
Reflections on F-theory Phenomenology
BSMW05 27th June 2012
16:15 to 16:30
Mixed Wino-Axion Dark Matter in String/M Theory and the 130 GeV gamma-line "Signal"
String/M theory compactifications with low energy supersymmetry tend to predict that dark matter has two components: axions and WIMPs \cite{1004.5138,1204.2795}. In accord with this, we show that the tentative 130 GeV gamma-line signal reported in \cite{1204.2797} can be interpreted as arising from the annihilation of 145 GeV mass, Wino-like WIMPs into a Z-boson and a photon. In this context, the signal implies a second component of dark matter which we interpret as being composed of axions - the relative Wino/Axion abundances being approximately equal. Further predictions are implied: signals in both diffuse and monochromatic photons from dwarf spheroidal galaxies; monochromatic photons with energy 145 GeV; for the LHC, the Higgs boson mass has been predicted in this framework \cite{1112.1059}, and the current Higgs limits provide interesting constraints on the mass of the Gluino.
BSMW05 27th June 2012
16:15 to 16:30
The Conifold's Competing Condensates
We discuss holographic superconductivity in the context of IIB on AdS_5 x T^{1,1}. In the spectrum on the gravity side, there are several modes with potential instabilities. In addition to the one identifed by Gubser et al, we point out that there is another, potentially more unstable mode. Moreover, we propose a concrete model for the dynamics of this mode. With this proposal at hand, we show that it indeed dominates the thermodynamics at low temperatures.
BSMW05 27th June 2012
16:30 to 16:45
S Watson How UV sensitive is inflation?
We investigate the validity of effective field theory methods and the decoupling of heavy fields during inflation. Considering models of inflation in which the inflaton is coupled to heavy degrees of freedom, we find that violations of decoupling are absent unless there is a breakdown of the slow-roll conditions. Next we allow for a temporary departure from inflation resulting in a period of non-adiabaticity during which effective field theory methods are known to fail. We find that the locality of the event and energy conservation lead to a tight bound on the size of the effects of the heavy field.
BSMW05 27th June 2012
16:30 to 16:45
Quasi- Poisson structures, Courant algebroids and Bianchi identities for non-geometric fluxes
The notion of non-geometric flux was introduced in string theory to correctly describe the degrees of freedom in four-dimensional effective superpotentials of type II flux compactifications. Whereas the H-flux is simply the field strength of the NS-NS B-field and the f-flux can be interpreted as the structure constants of a non-holonomic basis of the tangent bundle, the physical and mathematical properties of the remaining Q- and R-fluxes are to a great extent unknown. In this talk, we will first use the notion of a (quasi-)Poisson structure to re-derive directly on the tangent bundle the commutation relations containing all four fluxes as structure constants. As a consequence, we get Bianchi-type identities for the fluxes by writing down the Jacobi-identities for the algebra. Using these Bianchi-identities and the theory of quasi Lie-algebroids, we are able to identify the associated Courant algebroid structure, which is essential for dealing with all fluxes being non-zero.
BSMW05 27th June 2012
16:45 to 17:00
Collider Phenomenology of String/M Theory
Very generic string/M theory assumptions can lead to non-trivial phenomenologies that can be tested at the LHC. The branching fraction to the 3rd family quarks of the gluino decay should be enhanced, leading to multi-lepton and/or multi-bjet signatures. On the other hand, chargino could have long enough lifetime to produce disappearing tracks in the detector.
BSMW05 27th June 2012
16:45 to 17:00
Moduli Dependence of M5-instantons in F-theory
M5-instanton corrections to the superpotential in four-dimensional F-theory compactifications have a moduli-dependent prefactor which contains interesting physical content. In two examples obtained via heterotic duality, I will show that the entire vanishing locus of the prefactor can be understood via simple F-theory physics, often occurring at enhanced symmetry points in the complex structure moduli space. If time permits, I will discuss the relationship between line bundle cohomology on a distinguished curve in the instanton worldvolume and the intermediate Jacobian of the M5-instanton.
BSMW05 27th June 2012
17:15 to 17:30
R Davies Dirac gauginos and unification in F-theory
In the MSSM, the gauginos are assumed to acquire Majorana masses after supersymmetry breaking. If the light spectrum is extended slightly to include chiral multiplets in the adjoint representation of the gauge group, they can instead acquire Dirac masses by pairing up with the fermionic components of these multiplets. Dirac gauginos have several interesting properties, not least that they can be significantly heavier than Majorana gauginos, without paying any price in naturalness; this becomes particularly interesting in the light of the null results of the 2011 LHC searches for superpartners. One good reason for a theory to contain Dirac gauginos is if it has an unbroken (approximate) R-symmetry. In string theory, the construction of models with adjoint chiral fields and (optionally) an unbroken R-symmetry poses different problems to constructing the MSSM, especially as the gauge couplings no longer unify unless further matter is present. I will discuss solutions to some of these problems within the context of F-theory.
BSMW05 27th June 2012
17:15 to 17:30
Systematic Investigations of the Heterotic String Landscape
Results are reviewed for the first stages of Baylor University’s ongoing systematic statistics investigations of the parameter space of free fermionic heterotic string models. Presented is the complete set of D = 4, 6 models with either maximal or completely broken spacetime SUSY that are constructed from the untwisted sector and exactly one additional gauge sector containing anywhere from order 2 through 32 twists. All additional models generated to date with additional twisted gauge sectors are also discussed. A vast degeneracy among models appears: from the roughly 2 billion D = 4 models with a single twist sector, only 577 physically distinct models appear. 68 of these have N = 4 SUSY and 509 have completely broken SUSY. To date, no new physically distinct models appear among any of those formed from two or more twisted gauge sectors. Several redundancies among D= 4 models and among D= 6 models are proven to result from redundancies already present among D= 10 models . Methods to reduce redundancies in D= 4, 6 systematic searches are summarized. Statistics regarding the appearance of various combinations of gauge group factors and of GUT groups among the set of 577 physically unique models are presented. Lastly, moving briefly to models with matter sectors, a model with an even number D of large space-time dimensions is shown to always have maximal SUSY, if it is formed from the untwisted sector and a sector with a massless left-mover and an odd ordered right-mover.
BSMW05 27th June 2012
17:30 to 17:45
S Khalil TeV scale SUSY B-L
We propose a scheme where the three relevant physics scales related to the supersymmetry, electroweak, and baryon minus lepton (B-L) breakings are linked together and occur at the TeV scale. The phenomenological implications in the Higgs and leptonic sectors are discussed.
BSMW05 27th June 2012
17:30 to 17:45
B Jurke Scanning for Swiss Cheese geometries
Moduli stabilization in the Large Volume Scenario requires a specific kind of six-dimensional Calabi-Yau geometry for the compactification procedure, which is being referred to as "Swiss Cheese" due to the presence of certain holes for instanton wrappings. Only a handful of such manifolds are known explicitly. I will give an overview of the Large Volume Scenario and present recent progress on a general scan of the Calabi-Yau threefold landscape for the Swiss Cheese property.
BSMW05 27th June 2012
17:45 to 18:00
p-adic Strings at Finite Temperature
We study the finite temperature theory of p-adic string models. We analyze the partition function and main thermodynamic properties arising from perturbative thermal loops. We find that the thermal properties of these non-local field theories can be interpreted either as contributions of standard thermal modes with energies proportional to the temperature, or inverse thermal modes with energies proportional to the inverse of the temperature, leading to a thermal duality at leading order analogous to the well known T-duality of string theory.
BSMW05 27th June 2012
17:45 to 18:00
B Heidenreich Orientifolds and new N=1 Dualities
I report on a new class of N=1 dualities relating different gauge theories arising from D3 branes probing orientifold singularities. These dualities provide new, nontrivial solutions to the 't Hooft anomaly matching conditions. I discuss an infinite class of orbifold singularities where the duality can be interpreted as S-duality in ten dimensions. I also discuss non-orbifold singularities, and the microscopic interpretation of the duality in terms of an orientifold transition between compact O7+ and O7- planes.
BSMW05 28th June 2012
09:00 to 09:35
Type II and F-theory Instanton Effects
We address D-instanton contributions to the non-perturbative superpotential in Type II and F-theory, employing multi-pronged approaches, including heterotic and M-theory dualities. We focus focus on the determination of instanton zero modes and their contributions to the superpotential Pfaffian structure.
BSMW05 28th June 2012
09:35 to 10:10
Fluxes and Warping in F-theory
We discuss the effective theory of F-theory compactifications by using the M-theory dual. Two main results are highlighted: (1) the chiral index of a 4D F-theory compactification can be determined by four-form flux when comparing 3D Chern-Simons theories at one loop, (2) the inclusion of warping effects due to fluxes in M-theory is crucial to determine corrections to the F-theory effective theory even if in the latter warping effects can be neglected.
BSMW05 28th June 2012
10:10 to 10:45
Dark Matter density and the Higgs mass in LVS String Phenomenology.
BSMW05 28th June 2012
11:20 to 11:55
F Marchesano Yukawas in F-Theory
BSMW05 28th June 2012
11:55 to 12:30
Wavefunctions and local models in F-theory
I will discuss general aspects of wavefunctions and their overlaps in local F-theory models with an aim towards developing the ideas of ultra local model building.
BSMW05 28th June 2012
14:00 to 14:35
S Schafer-Nameki F-theory and G-flux
BSMW05 28th June 2012
14:35 to 15:10
T Weigand Gauge fluxes and M5-instantons in F-theory and their Type IIB duals
I discuss recent progress in the description of G4 gauge fluxes in F-theory compactifications on Calabi-Yau fourfolds. Such fluxes are important from the perspective of F-theory model building, where gauge fluxes are required for example for the generation of chiral matter. An explicit dictionary between a class of factorisable G4 fluxes in certain F-theory compactifications and corresponding diagonal U(1) fluxes in Type IIB orientifolds sheds new light on the uplift of Type IIB vacua to F-theory. This global description of gauge fluxes in F-theory also allows for the evaluation of selection rules for M5-instantons to contribute to the superpotential.
BSMW05 28th June 2012
15:10 to 15:45
Non-abelian discrete gauge symmetries in string theory
I will discuss the realization of non-abelian discrete gauge symmetries in field theory and string theory, and present several classes of string models exhibiting non-abelian discrete gauge symmetries. In models of magnetized/intersecting D-branes, the discrete symmetries impose non-trivial constraints on Yukawa couplings, and correspond to interesting flavour symmetries in MSSM-like models.
BSMW05 28th June 2012
16:15 to 16:30
S Groot Nibbelink Super Weyl invariance: BPS equations from heterotic worldsheets
It is well-known that the beta functions on a string worldsheet correspond to the target space equations of motion, e.g. the Einstein equations. We show that the BPS equations, i.e. the conditions of vanishing supersymmetry variations of the space-time fermions, can be directly derived from the worldsheet. To this end we consider a heterotic worldsheet model in the RNS-formulation with (2,0) supersymmetry, which describes a complex torsion target space that supports a holomorphic vector bundle. After a detailed account of its quantization and renormalization, we establish that super Weyl anomaly cancellation implies the heterotic BPS conditions: At the one loop level the geometry is required to be conformally balanced and the gauge background has to satisfy the Hermitean Yang-Mills equations.
BSMW05 28th June 2012
16:15 to 16:30
Towards the Standard Model on Rigid D-Branes
D-brane worlds have provided a geometrically intuitive approach for Standard Model (SM) engineering within string theory compactifications. While the types and ranks of gauge groups and the chiral matter content are tackled in a straightforward manner, it remains on the one hand an open question if the SM can be obtained on rigid D-branes - without continuous gauge symmetry breaking along flat directions and with non-trivial D-brane instanton contributions to the effective action - and on the other hand if such models are consistent with low-energy data. The T6/Z(2)xZ(6') orbifold with discrete torsion admits a plethora of left-right symmetric `local models' without exotic matter in the adjoint, symmetric or antisymmetric representation. However, `global' completions usually come at the cost of introducing new exotic states in bifundamental representations. It furthermore turns out that USp(2) and SO(2) in place of U(2) symmetries can at most provide one particle generation. Last but not least, it turns out that for any T6/Z(2)xZ(2M) orbifold with discrete torsion and tilted tori, orientifold invariant stacks of D6-branes carry USp(2N) or SO(2N) gauge groups depending on their relative position to the exotic O6-plane. The new classification reduces the number of K-theory constraints. If time permits, I will briefly comment on the drastic change in the pattern of Yukawa couplings on orbifolds compared to the six-torus using a T6/Z6' example. As a result, quark Yukawas can provide large mixings while lepton Yukawas are flavour diagonal at leading order. Also the rule of `one massive generation only' is circumvented.
BSMW05 28th June 2012
16:30 to 16:45
GLSM descriptions of heterotic compactification spaces
Gauged Linear Sigma Models (GLSMs) provide a framework for studying different phases of compactification spaces for heterotic string theories. Among them are toroidal orbifolds and smooth Calabi-Yau constructions, both of which are very popular among string model builders. Up to now, quite a few MSSM-like string models have been constructed based on these compactification spaces. We describe the construction of toroidal orbifolds and describe how to obtain their smooth Calabi-Yau counterparts in the GLSM framework. The two regimes lie at different regions in Kahler moduli space, which can be accessed by tuning the Fayet-Iliopoulos GLSM parameters. However, upon probing the entire moduli space, also other phases are encountered which do not have a geometric interpretation as straightforward as the previously mentioned ones. Furthermore, there can be flop and flop-like transitions which further subdivide the different phases.
BSMW05 28th June 2012
16:30 to 16:45
Superpotential de-sequestering as a source of flavour violation
Non-perturbative effects such as gaugino condensation on a stack of D7-branes are an essential ingredient in several celebrated moduli-stabilisation schemes in type IIB string theory. At the level of the four-dimensional effective theory, the non-perturbative effects induce a non-perturbative superpotential. In particular, new Yukawa interactions can be generated. Type IIB orbifold models contain the essential features to study these non-perturbative corrections to the superpotential in string compactifications. I will describe under which conditions new Yukawa couplings arise in these settings and generalise the results to more realistic string models. Most importantly, I will show that the flavour structure of the induced Yukawa couplings is not aligned with the tree-level flavour structure, thus introducing a new source of flavor violation.
BSMW05 28th June 2012
16:45 to 17:00
S Parameswaran Coupling Selection Rules in Heterotic Orbifold Compactifications
Heterotic orbifolds provide a simple, globally consistent framework in which one can obtain the MSSM particle spectrum with no chiral exotics from string theory. In order to understand the dynamical aspects and phenomenology of these compactifications, such as the decoupling of vector-like exotics, moduli stabilization, particle masses and couplings, we must compute the couplings in the corresponding low energy effective field theory.

We study L-point string correlation functions and thus derive string selection rules, which determine the allowed couplings in the superpotential of the low energy effective supergravity theory.
BSMW05 28th June 2012
16:45 to 17:00
The Coulomb Gas of Random Supergravities
I will discuss the mass spectrum of four-dimensional {\cal N}=1 supergravity in which the Kähler potential and superpotential are taken to be random functions of N chiral superfields. For both supersymmetric and non-supersymmetric critical points, the ensemble of Hessian matrices can be efficiently studied through the ‘Coulomb gas’ formulation of Random Matrix Theory. At large N, the supersymmetric AdS vacua have a very peculiar spectrum which typically includes many BF-allowed tachyons, and I will briefly discuss the prospects of obtaining metastable de Sitter vacua from an ‘uplift’ of a supersymmetric AdS vacuum. An exponentially small fraction de Sitter critical points with spontaneously broken supersymmetry are metastable vacua, and I will discuss how the Coulomb gas formulation can be used to find the joint probability distribution of the masses, the fraction of critical points which are vacua, and the spectrum of the vacua. I will conclude by b riefly discussing some cosmological consequences of these results.
BSMW05 28th June 2012
17:15 to 17:30
U(n) Spectral Covers from Decomposition
We construct decomposed spectral covers for bundles on elliptically fibered Calabi-Yau threefolds whose structure groups are S(U(1) x U(4)), S(U(2) x U(3)) and S(U(1) x U(1) x U(3)) in heterotic string compactifications. The decomposition requires not only the tuning of the SU(5) spectral covers but also the tuning of the complex structure moduli of the Calabi-Yau threefolds. This configuration is translated to geometric data on F-theory side. We find that the monodromy locus for two-cycles in K3 fibered Calabi-Yau fourfolds in a stable degeneration limit is globally factorized with squared factors under the decomposition conditions. This signals that the monodromy group is reduced and there is a U(1) symmetry in a low energy effective field theory. To support that, we explicitly check the reduction of a monodromy group in a slice of the moduli space for an E6 gauge theory with (1+2) decomposition. This may provide a systematic way for constructing some F-theory models with U (1) symmetries.
BSMW05 28th June 2012
17:15 to 17:30
Exceptional Flux Compactifications
In the last decade, a framework in which string dualities are implemented at the supergravity level has been developed, i.e., the so-called embedding tensor formalism. However, the connection between this formalism and string theory realisations remains still obscure since most of the supergravities obtained by using the embedding tensor formalism correspond to very exotic (non-)geometries in the string side.

In this talk we consider type II flux backgrounds compatible with the absence of brane sources, and construct their explicit embedding into maximal D=4 supergravity. This enables us to investigate the critical points, mass spectra and gauge groups of such "exceptional" backgrounds in a systematic way. We will chart the landscape of vacua in some specific setups which are relevant from the string theory viewpoint and discuss the issues of stability and supersymmetry at those vacuum solutions. Finally we will point towards some natural extensions of the results.
BSMW05 28th June 2012
17:30 to 17:45
C Mayrhofer Searching for Phenomenologically Attractive Calabi-Yaus with Kähler Classes Variant under Orientifolding
We give a detailed account of our search for Calabi-Yau three-folds with two toric del Pezzo divisors of the same kind and an orientifold involution which maps them into each other. We will consider hypersurface Calabi-Yaus in toric four-folds with $h^{1,1}$ up to five and comment on the relevance of these geometries in string phenomenology.
BSMW05 28th June 2012
17:30 to 17:45
A Borghese A geometric bound for F-term inflation
There has been a lot of efforts during the last decade in order to provide a supergravity realisation of inflation. This is of crucial importance if one look at supergravity as the bridge connecting the effective field theory of inflation and a possible UV complete theory like string theory. Within a supergravity theory the inflationary dynamics is tightly constrained. I will discuss a particular kind of geometric constraints which arise by considering particular directions on the scalar manifold, namely the ones which are singled out by the process of supersymmetry breaking (the so called sGoldstino’s). As an example I will consider the constraint in the case of N=1, F-term inflation.
BSMW05 28th June 2012
17:45 to 18:00
Model building and moduli stabilisation in Calabi-Yau orientifold compactifications with branes at singularities
BSMW05 28th June 2012
17:45 to 18:00
On the Beaming of Gluonic Fields at Strong Coupling
We examine the conditions for beaming of the gluonic field sourced by a heavy quark in strongly-coupled conformal field theories, using the AdS/CFT correspondence. Previous works have found that, contrary to naive expectations, it is possible to set up collimated beams of gluonic radiation despite the strong coupling. We show that, on the gravity side of the correspondence, this follows directly (for arbitrary quark motion, and independently of any approximations) from the fact that the string dual to the quark remains unexpectedly close to the AdS boundary whenever the quark moves ultra-relativistically. We also work out the validity conditions for a related approximation scheme that proposed to explain the beaming effect though the formation of shock waves in the bulk fields emitted by the string. We find that these conditions are fulfilled in the case of ultra-relativistic uniform circular motion that motivated the proposal, but unfortunately do not hold for much more gen eral quark trajectories.
BSMW05 29th June 2012
09:00 to 09:35
L Ibanez The SUSY breaking scale and F-theory unification
BSMW05 29th June 2012
09:35 to 10:10
AN Schellekens Discrete gauge symmetries in discrete orientifolds
We study the origin of discrete gauge symmetries from open string sector U(1)'s in orientifolds based on rational conformal field theory. By means of an explicit construction, we find an integral basis for the couplings of axions and U(1) factors for all simple current MIPFs and orientifolds of all 168 Gepner models, a total of 32990 distinct cases. We discuss how the presence of discrete symmetries surviving as a subgroup of broken U(1)'s can be derived using this basis. We apply this procedure to models with MSSM chiral spectrum, concretely to all known U(3)xU(2)xU(1)xU(1) and U(3)xSp(2)xU(1)xU(1) configurations with chiral bi-fundamentals, but no chiral tensors, as well as some SU(5) GUT models.
BSMW05 29th June 2012
10:10 to 10:45
The Dark OPERA
BSMW05 29th June 2012
11:20 to 11:55
Phenomenological Heterotic Theory: Standard Models, the Renormalization Group and All That
A class of hidden sector polystable vector bundles will be presented that, when used in combination with SU(4) heterotic standard model bundles, lead to completely stable string vacua with exactly the particle spectrum of the MSSM with three right-handed neutrino supermultiplets. Threshold corrections, the effective Lagrangian with soft supersymmetry breaking and its scaling under the renormalization group are discussed. It is shown that gauged B-L symmetry and electroweak symmetry are radiatively broken with a small hierarchy over a wide range of initial parameters. Implications of these SU(4) heterotic standard models for the LHC are explored.
BSMW05 29th June 2012
11:55 to 12:30
Heterotic Line Bundle Models in Four Dimensions
We introduce heterotic line bundle standard models and, more generally, heterotic split models focusing on their four-dimensional effective supergravity theories. The general structure of these theories and a number of phenomenological issues, including fermion masses, proton decay and moduli stabilization will be discussed.
BSMW05 29th June 2012
12:30 to 12:35
Announcement of String Pheno 2013
BSMW05 29th June 2012
14:00 to 14:35
G Dall'agata New facts on classical and quantum N=8 supergravity
N=8 supergravity is currently at the center of many investigations because of its possible ultraviolet finiteness. I will present some new results on its spontaneously broken version. I will prove that all models with N=0 Minkowski vacua are finite at 1-loop. I will also discuss a new mechanism to study the classical vacua, show that there are many more deformations than previously expected and that from a stringy perspective broken N=8 supergravity exhibits a moduli space with some intriguing features.
BSMW05 29th June 2012
14:35 to 15:10
I Garcia-Etxebarria New N=1 dualities from contracting orientifolds
I will describe recent work on a new class of dualities, directly inherited from IIB S-duality, in 4d theories with 4 supercharges.

I will focus on the microscopic description of the duality, when realized in terms of system of branes at singularities in string theory. The theories in question are obtained by considering, in addition to the fractional branes, orientifold planes wrapping vanishing 4-cycles.

I will discuss the system from the point of view of large volume branes, focusing in particular on the relevant issues when continuing orientifolds of quiver gauge theories to large volume. This discussion provides a first principles derivation of the relevant orientifolded quivers. By studying the strongly coupled behavior of the resulting orientifold+brane configuration, I will argue for the existance of a dual, weakly coupled description of the strongly coupled quiver theory at the singularity.
University of Cambridge Research Councils UK
    Clay Mathematics Institute London Mathematical Society NM Rothschild and Sons