An Isaac Newton Institute Workshop

Quantum Information Theory: Present Status and Future Directions

Picturing qubits in phase space

23rd August 2004

Author: W. Wootters (Williams College)


In this talk I present a discrete-phase-space description of a system of qubits, in which each phase-space axis is labeled by the elements of a finite field and the state of the system is represented by a real function on phase space--a discrete Wigner function. Each set of parallel lines in the phase space corresponds to an orthogonal basis for the state space, and bases corresponding to different sets of parallel lines are mutually unbiased. I discuss the representation of quantum gates in this framework, and the problem of recognizing entanglement