09:00 to 09:45 Spatially modulated phases in holography Spatially modulated phases are widespread in nature. Holographically they are described by novel black hole solutions. The talk will focus on two topics. The first is some general results on the thermodynamics of periodic black branes. The second is the construction of some new superconducting p-wave and (p+ip)-wave black holes. INI 1 09:45 to 10:30 Striped order in AdS/CFT Co-authors: Darren Smyth (UBC), Evgeny Sorkin (UBC), Jared Stang (UBC) I discuss the formation of inhomogeneous order in the Einstein-Maxwell-axion system, dual to a 2+1 dimensional field theory that exhibits a spontaneously generated current density, momentum density and modulated scalar operator. Below the critical temperature, the Reissner-Nordstrom-AdS black hole becomes unstable and stripes form in the bulk and on the boundary. The bulk geometry possesses striking geometrical features, including a modulated horizon that tends to pinch off as T goes to 0. The phase transition to the formation of stripes is of second order. INI 1 10:30 to 11:00 Morning Coffee 11:00 to 11:45 T Gasenzer (Universität Heidelberg)Non-thermal fixed points: universality, topology, & turbulence in Bose systems Co-authors: Sebastian Erne (Universität Heidelberg, Germany), Markus Karl (Universität Heidelberg, Germany), Boris Nowak (Universität Heidelberg, Germany) Among the wealth of possible non-equilibrium many-body configurations most interesting candidates are those which show universal behavior. New, non-thermal fixed points are proposed, leading beyond standard equilibrium critical points. A selection of phenomena in ultracold Bose gases, characterized by specific power-laws in space and time, and universal time evolution will be presented. These are, for generic cases, related to the presence and turbulent dynamics of (quasi-)topological defects in the Bose field, which are manifestly far from equilibrium. Examples how to reach these critical points which will be discussed include interaction quenches and rapid evaporative cooling. Our results confirm non-perturbative quantum field theoretical predictions and establish a new link between kinetic wave turbulence and topological excitations of superfluids. They open a path to explore a new class of universal far-from-equilibrium dynamics well accessible in ultracold gas experiment s. These phenomena are of importance far beyond the realm of cold gases and allow a view on new classifications of universal far-from-equilibrium physics. INI 1 11:45 to 12:30 Holographic turbulence Co-authors: Hong Liu (MIT), Allan Adams (MIT) According to holography, turbulent flows in relativistic boundary conformal field theories should be dual to dynamical black hole solutions in asymptotically AdS_{d+2} spacetime with d the number of spatial dimensions the turbulent flow lives in. This immediately raises many interesting questions about gravitational dynamics. For example, what distinguishes turbulent black holes from non-turbulent ones? What is the gravitational origin of energy cascades and the Kolmogorov scaling observed in turbulent fluid flows? We construct turbulent black holes in asymptotically AdS_4 spacetime by numerically solving Einstein's equations. Both the dual holographic fluid and bulk geometry display signatures of an inverse cascade with the bulk geometry being well approximated by the fluid/gravity gradient expansion. I will argue that statistically steady-state black holes dual to d dimensional turbulent flows have horizons which are approximately fractal with fractal dimension D = d + 4/3. Time permitting I will discuss qualitative differences between holographic superfluid turbulence normal fluid turbulence. INI 1 12:30 to 13:30 Lunch at Wolfson Court 14:00 to 14:45 Entanglement entropy in higher spin theories A holographic correspondence has been recently developed between higher spin theories in three-dimensional anti-de Sitter space (AdS_3) and two-dimensional Conformal Field Theories (CFTs) with extended symmetries. A class of such dualities involves SL(N,R)\times SL(N,R) Chern-Simons gauge theories in the (2+1)-dimensional bulk spacetime, and CFTs with W_N symmetry algebras on the (1+1)-dimensional boundary. The topological character of the Chern-Simons theory forces one to reconsider standard geometric notions such as black hole horizons and entropy, as well as the usual holographic dictionary. Motivated by this challenge, in this note we present a proposal to compute entanglement entropy in the W_N CFTs via holographic methods. In particular, we introduce a functional constructed from Wilson lines in the bulk Chern-Simons theory that captures the entanglement entropy in the CFTs dual to standard AdS_3 gravity, corresponding to SL(2,R)\times SL(2,R) gauge group, and admits an immediate generalization to the higher spin case. We explicitly evaluate this functional for several known solutions of the Chern-Simons theory, including charged black holes dual to thermal CFT states carrying higher spin charge, and show that it reproduces expected features of entanglement entropy, study whether it obeys strong subadditivity, and moreover show that it reduces to the thermal entropy in the appropriate limit. INI 1 14:45 to 15:30 Effective field theories for topological insulators via functional bosonization Eﬀective ﬁeld theories that describes the dynamics of a conserved U(1) current in terms of “hydrodynamic” degrees of freedom of topological phases in condensed matter are discussed in general dimension D = d+1 using the functional bosonization technique. For non-interacting topological insulators (superconductors) with a conserved U(1) charge and characterized by an integer topological invariant, we derive the BF-type topological ﬁeld theories supplemented with the Chern-Simons (when D is odd) or the θ-term (when D is even). For topological insulators characterized by a Z2 topological invariant (the ﬁrst and second descendants of the primary series), their topological ﬁeld theories are obtained by dimensional reduction. Building on this eﬀective ﬁeld theory description for noninteracting topological phases, we also discuss, following the spirit of the parton construction of the fractional quantum Hall eﬀect by Block and Wen, the putative “fractional” topological insulators and their possible eﬀective ﬁeld theories, and use them to determine the physical properties of these. INI 1 15:30 to 16:00 Afternoon Tea 16:00 to 16:45 The IR landscape of holography: Cohesive and fractionalised phases, insulators and bad metals. Co-authors: Blaise Gouteraux (Nordita), Aristos Donos (Cambridge) All scaling IR asymptotics in homogeneous, translation invariant holographic phases with a (potentially broken) U(1) symmetry in the IR are classified. The general critical saddle-point solutions are characterized by four critical exponents ($\theta, z$) for the metric as well as the scaling of the electric potential and electric flux . Neutral or charged geometries realizing both fractionalized or cohesive phases are found. In the presence of helical invariance, (breaking translational invariance), new universality classes are possible that correspond to insulators and bad metals. INI 1 16:45 to 17:30 Newton-Cartan geometry and the quantum Hall effect Co-authors: Siavash Golkar (University of Chicago), Dung Xuan Nguyen (University of Chicago) We construct an effective field theory for quantum Hall states, guided by the requirements of nonrelativistic general coordinate invariance and regularity of the zero mass limit. We propose Newton-Cartan geometry as the most natural formalism to construct such a theory. Universal predictions of the theory are discussed. We also derived new sum rules for fractional quantum Hall states. INI 1 19:30 to 22:00 Conference Dinner at St. Catharine's College
 09:00 to 09:45 S Gubser (Princeton University)Finite momentum at string endpoints Co-authors: Andrej Ficnar (Columbia University) Classical string solutions exist with finite momentum at endpoints. I will explain the main features of finite endpoint momentum, including an extension of the Green-Schwarz action. Finite endpoint momentum is useful in the study of holographic energy loss by light quarks. I will show how simple analytic methods suffice to extract the main features of the relevant string motions, and I will present some preliminary phenomenological results. INI 1 09:45 to 10:30 K Schalm (Universiteit Leiden)Far from equilibrium dynamics in CFTs and holography Co-authors: M.J. Bhaseen (King's College), Benjamin Doyon (King's College), Andrew Lucas (Harvard). Abstract: We investigate far from equilibrium energy transport in strongly coupled quantum critical systems. Combining results from gauge-gravity duality, relativistic hydrodynamics, and quantum field theory, we argue that long-time energy transport occurs via a universal steady-state for any spatial dimensionality. This state can be uniquely identified as a Lorentz boosted thermal state. INI 1 10:30 to 11:00 Morning Coffee INI 1 11:00 to 11:45 Numerical relativity and far-from-equilibrium dynamics A variety of gravitational dynamics problems in asymptotically anti-de Sitter (AdS) spacetime are amenable to efficient numerical solution using a common approach involving a null slicing of spacetime based on infalling geodesics, convenient exploitation of the residual diffeomorphism freedom, and use of spectral methods for discretizing and solving the resulting differential equations. After describing the approach, recent results on colliding planar shock waves are presented. The validity of hydrodynamics and the applicability of "local" boost invariance in describing the outgoing flow is examined. INI 1 11:45 to 12:30 SS Lee (McMaster University)Quantum renormalization group and holography In this talk, I will discuss about the quantum renormalization group and its connection to holography. Via quantum renormalization group procedure, one can show that the holographic dual for an idealized matrix field theory which has no other operator with finite scaling dimension besides the energy-momentum tensor is the Einstein gravity upto two derivative order. INI 1 12:30 to 13:30 Lunch at Wolfson Court INI 1 14:00 to 14:45 A holographic model of the Kondo effect Coauthors: C. Hoyos (Tel Aviv Univ.), A. O'Bannon (DAMTP Cambridge), J. Wu (NCTS Taiwan) We propose a holographic model of the Kondo effect, i.e. of the screening of a magnetic impurity coupled to a bath of conduction electrons at low temperatures. In a (1+1)-dimensional CFT description, this corresponds to an RG flow from an UV to an IR fixed point triggered by a marginally relevant (0+1)-dimensional operator. In the large N limit, with spin SU(N) and charge U(1) symmetries, the Kondo effect appears as a mean-field phase transition in which the U(1) symmetry is spontaneously broken. Inspired by a top-down brane model, we model the Kondo RG flow by an AdS_3 Chern-Simons action coupled to an AdS_2 holographic superconductor. We observe several characteristic features of the Kondo effect in this model, such as dynamical scale generation and a phase shift. Moreover, we find a power-law behaviour of the resistivity with temperature which is consistent with over-screening. Our model may serve as a basis for investigating more involved problems such as Kondo lattices. INI 1 14:45 to 15:15 Universal scaling properties of holographic cohesive phases Co-author: Kiritsis, Elias (University of Crete) In this talk, we focus on zero-temperature, strongly-coupled, translation-invariant holographic phases at finite density. We show that they can be classified according to the scaling behavior of the metric, the electric potential and the electric flux. Solutions fall into two classes, depending on whether they break relativistic symmetry or not. We conjecture a universal scaling for the optical conductivity at zero temperature and low frequencies, which reduces to the correct result for both classes of solutions. INI 1 15:15 to 15:45 Afternoon Tea 15:45 to 16:15 YL Zhang (Chinese Academy of Sciences)Petrov type $I$ Spacetime and Dual Hydrodynamics Co-authors: Rong-Gen Cai (Institute of Theoretical Physics, Chinese Academy of Sciences), Kostas Skenderis (University of Southampton) It has been shown that imposing a Petrov type $I$ condition on a $(p+1)$-dimensional timelike hypersurface embedded in a $(p+2)$-dimensional vacuum Einstein gravity reduces the degrees of freedom in the extrinsic curvature of the hypersurface to that of a fluid on the hypersurface. We show that the Relativistic fluid dual to vacuum Einstein gravity does satisfy the covariant Petrov type $I$ condition at least up to second order in derivative expansion. In addition, we show that this procedure can be inversed to derive the relativistic hydrodynamics with higher order corrections through imposing the Petrov type $I$ condition, and that some second order transport coefficients can also be extracted. Coset model for the Luttinger liquid INI 1 16:15 to 17:00 GW Semenoff (University of British Columbia)Quantum hallography A new holographic description of defect field theories using probe D5 branes is discussed. We consider a system where a large number of probe branes, which are asymptotically D5 branes blow up into a D7 brane suspended in the bulk of anti-de Sitter space. For a particular ratio of charge density to external magnetic field, so that the Landau level filling fraction is exactly one, the D7 brane exhibits an incompressible, charge gapped state with one unit of integer quantized Hall conductivity. We also show that states with integer filling fractions greater than one are multiple D7 branes. We also see that compressible states can be those of D7 rather than D5 branes and we outline what is known about the phase diagram. INI 1