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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:2
UID:UW-Physics-Event-8183
DTSTART:20230213T170000Z
DTEND:20230213T180000Z
DTSTAMP:20260414T033143Z
LAST-MODIFIED:20230213T225211Z
LOCATION:5310 Chamberlin Hall 
SUMMARY:The geometry of quantum error correction under biased noise\, 
 Atomic Physics Seminar\, Arpit Dua
DESCRIPTION:Quantum error correction is necessary because physical qub
 its have much higher error rates per gate operation than are needed fo
 r practical tasks. The popular choice is to encode a logical qubit in 
 a large enough planar layout of many physical qubits\, called the surf
 ace code\, to have sufficiently low logical error rates. The optimal l
 ogical error rates depend on the statistical mechanics of logical oper
 ators. For example\, under biased Pauli noise\, having more higher-wei
 ght logical operator representations with a higher ratio of low-rate P
 auli operators is better. Using this idea\, I will discuss how\, in ac
 tive error correction\, measuring Clifford-rotated Pauli stabilizers o
 f the surface code can enhance code performance: higher error threshol
 ds and lower subthreshold logical error rates\, for biased Pauli noise
 . Using statistical mechanics and percolation theory\, I will describe
  a phase diagram of 50% thresholds for random Clifford-rotated surface
  codes under pure dephasing noise. Using tensor network numerics\, I w
 ill show that certain families of these random codes outperform the be
 st-known translation invariant Clifford-rotated surface codes for fini
 tely biased depolarizing noise. 
URL:https://www.physics.wisc.edu/events/?id=8183
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