Quantum Institute: Visitor Schedule

The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.
For more information, contact Diego Dalvit.

April 3, 2008
Thursday, 12:30 PM to 2 PM

Speaker: Graeme Smith, IBM

Technical Host: Jon Yard

TOPIC: Capacities of a Quantum Channel with Symmetric Assistance

Abstract

In classical information theory, there is a neat formula for the private capacity of a channel. This problem has two quantum analogs, the private classical capacity of a quantum channel, and the quantum capacity (necessarily private) of a quantum channel, neither of which is as nice. Indeed, these capacities are unknown for all but a handful of channels. I will discuss these capacities in a scenario supplemented by a symmetric side channel, which by itself has no quantum or secret capacity. Including this extra resource results in a dramatic simplification the capacities are additive, convex, and single letter and gives strong upper bounds on the unassisted capacities of several channels of interest.