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IQIM Postdoctoral and Graduate Student Seminar

Wednesday, August 3, 2022
11:00am to 12:00pm
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Annenberg 105
An efficient decoder for a linear distance quantum LDPC code
Bailey Gu & Chris Pattison, Preskill Group,

Joint IQIM/AWS Seminar

Abstract: Quantum low-density parity-check (qLDPC) codes are quantum error correcting codes with constant-sized check weights. Among other applications, such codes can be used for low-overhead fault-tolerant quantum memories. Recent developments have shown the existence of qLDPC codes that possess a number of logical qubits and distance linear in the number of physical qubits. In this talk, we summarize a recent qLDPC code construction, Leverrier and ZĂ©mor's quantum Tanner codes, and describe an efficient decoder. The decoder operates using a "global potential function" for these codes, which is closely related to the syndrome weight. Our decoder is an iterative algorithm that searches for small sets of qubits to flip at every step in order to decrease the global potential. By using this procedure, we prove that the decoder runs in linear time and successfully corrects errors of weight up to a constant fraction of the blocklength.

This week's seminar will be presented in person and also on zoom


Meeting ID: 884 0762 7311
Passcode: 932356

Attendees joining in person must demonstrate that they comply with Caltech's vaccination requirements (Caltech ID or AWS ID required).

Amid the recent increase in COVID-19 cases on campus due to the arrival of the highly infectious BA.2 subvariant in Los Angeles County and a return to routine social activities, the Institute has reinstated its requirement that high-quality masks (surgical, N95s, KN95s, or KF95s) must be worn in all indoor locations on campus.

For more information, please contact Marcia Brown by phone at 626-395-4013 or by email at [email protected].