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IQI Weekly Seminar

Tuesday, February 5, 2019
3:00pm to 4:00pm
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Annenberg 107
Chasing Quantum Codes: how to Outsmart a Brute-Force Approach
Johannes Bausch, University of Cambridge,

Abstract: In the iid noise model, error correction crucially depends on the existence of good codes. In this context, "good" relates to an as-large-as-possible coherent information under the action of various noisy channels, such as depolarizing, dephrasure, or BB84. Each of these channels has a noise parameter p, which allows us to ask which codes are optimal for a particular choice of p. Existing upper bounds on the quantum capacity of the above channels are not known to be tight, and in certain noise regimes there is a large gap between upper and lower bounds on the quantum capacity.

Our goal is to find optimal codes under a family of states called "graph states". Such states often feature large symmetries, which together with a Pauli channel's properties (e.g. covariance) can be exploited to vastly reduce the numerical complexity of exhaustive search. We present a few prelimiary results.

This is a work-in-progress project jointly with Felix Leditzky (University of Colorado Boulder/JILA).

 

 

 

 

 

 

 

 

 

 

 

 

 

For more information, please contact Bonnie Leung by phone at 626.395.4964 or by email at [email protected].