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Thursday, November 10, 2011 12:00 pm - 12:30 pm EST (GMT -05:00)

Mary Beth Ruskai: A proposal for numerical tests of non-additivity for non-unital qubit channels

Mary Beth Ruskai, Tufts University

Abstract

Subtitle: A numerical project that needs HELP

After Shor's proof of equivalence of additivity conjectures, attention shifted from capacity and entanglement of formation to the seemingly easier questions of minimal output entropy. Despite existence proofs for non-additivity in high dimensions, explicit examples remain elusive. It may be that the violations for minimal output entropy are so small and require such large dimensions, that numerical searches won't find them.

Thursday, November 3, 2011 12:30 pm - 1:00 pm EDT (GMT -04:00)

Fred Shultz: Entanglement preservation

Fred Shultz, Wellesley College

Abstract

We will determine the possible maps that can describe time evolution preserving entanglement.

This will be approached by examining the convex set of separable states, and describing all symmetries of this set.

Joint work with Erik Alfsen of the University of Oslo.

Monday, October 31, 2011 12:30 pm - 1:30 pm EDT (GMT -04:00)

Fernando Brandao: Random quantum circuits are approximate polynomial-designs

Abstract

An approximate unitary t-design is a distribution of unitaries that mimic properties of the Haar measure for polynomials (in the entries of the unitaries) of degree up to t. It has been a conjecture in the theory of quantum pseudo-randomness that polynomial sized random quantum circuits form an approximate unitary poly(n)-design. Unfortunately, up to now, the best result known is that polynomial random quantum circuits are unitary 3-designs.