Southwest Quantum Information and Technology

Error suppression for quantum subsytem codes with weak measurement induced Zeno effect

Presenting Author: Bibek Pokharel, University of Southern California
Contributing Author(s): Gerardo Paz-Silva, Jason Dominy, Daniel Lidar

The goal of quantum error mitigation is to dampen and possibly eliminate, errors from quantum computation. While active quantum error correction involves a recovery step dependent on the errors identified, passive error mitigation is agnostic to the exact errors that occur during the computation. Weak measurement quantum Zeno effect (WMQZE) is a passive error mitigation method. Paz Silva et. al. [PRL, 108(8), p.080501] proved that weak measurement of stabilizers of a subspace code can induce a Zeno effect and correspondingly protect arbitrary encoded states to arbitrary accuracy while at the same time allowing for universal quantum computation. We extend their results to subsystem codes by proving that weak measurement of gauge operators, which form a non-Abelian group and are smaller in weight than the corresponding stabilizers of that code, can also protect arbitrary encoded states. We also numerically verify that for WMQZE-based protection works not just in the limit of infinitely many strong measurements, but also in experimentally accessible regimes. For the Bacon-Shor [[4,1,2]] code, we measure the gauge operators with varying measurement frequencies and strengths and report that in all cases attempted the protected state was more resistant to error than their unprotected counterparts.

(Session : from 5:00pm - 7:00pm)