Fault-tolerant quantum memory using low-depth random circuit codes

Low-depth random circuit codes possess many desirable properties for quantum error correction but have so far only been analyzed in the code capacity setting where it is assumed that encoding gates and syndrome measurements are noiseless. In this work, we design a fault-tolerant distillation protoco...

Full description

Saved in:
Bibliographic Details
Main Authors: Jon Nelson, Gregory Bentsen, Steven T. Flammia, Michael J. Gullans
Format: Article
Language:English
Published: American Physical Society 2025-01-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.7.013040
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1841546908719382528
author Jon Nelson
Gregory Bentsen
Steven T. Flammia
Michael J. Gullans
author_facet Jon Nelson
Gregory Bentsen
Steven T. Flammia
Michael J. Gullans
author_sort Jon Nelson
collection DOAJ
description Low-depth random circuit codes possess many desirable properties for quantum error correction but have so far only been analyzed in the code capacity setting where it is assumed that encoding gates and syndrome measurements are noiseless. In this work, we design a fault-tolerant distillation protocol for preparing encoded states of one-dimensional random circuit codes even when all gates and measurements are subject to noise. This is sufficient for fault-tolerant quantum memory since these encoded states can then be used as ancillas for Steane error correction. We show through numerical simulations that our protocol can correct erasure errors up to an error rate of 2%. In addition, we also extend results in the code capacity setting by developing a maximum likelihood marginal decoder for depolarizing noise similar to work by Darmawan et al. [Phys. Rev. Res. 6, 023055 (2024)2643-156410.1103/PhysRevResearch.6.023055]. As in their work, we formulate the decoding problem as a tensor network contraction and show how to contract the network efficiently by exploiting the low-depth structure. Replacing the tensor network with a so-called “tropical” tensor network, we also show how to perform minimum weight decoding. With these decoders, we are able to numerically estimate the depolarizing error threshold of finite-rate random circuit codes and show that this threshold closely matches the hashing bound even when the decoding is suboptimal.
format Article
id doaj-art-bb7bb9c9284c4b86b917ff8948dbff15
institution Kabale University
issn 2643-1564
language English
publishDate 2025-01-01
publisher American Physical Society
record_format Article
series Physical Review Research
spelling doaj-art-bb7bb9c9284c4b86b917ff8948dbff152025-01-10T15:07:46ZengAmerican Physical SocietyPhysical Review Research2643-15642025-01-017101304010.1103/PhysRevResearch.7.013040Fault-tolerant quantum memory using low-depth random circuit codesJon NelsonGregory BentsenSteven T. FlammiaMichael J. GullansLow-depth random circuit codes possess many desirable properties for quantum error correction but have so far only been analyzed in the code capacity setting where it is assumed that encoding gates and syndrome measurements are noiseless. In this work, we design a fault-tolerant distillation protocol for preparing encoded states of one-dimensional random circuit codes even when all gates and measurements are subject to noise. This is sufficient for fault-tolerant quantum memory since these encoded states can then be used as ancillas for Steane error correction. We show through numerical simulations that our protocol can correct erasure errors up to an error rate of 2%. In addition, we also extend results in the code capacity setting by developing a maximum likelihood marginal decoder for depolarizing noise similar to work by Darmawan et al. [Phys. Rev. Res. 6, 023055 (2024)2643-156410.1103/PhysRevResearch.6.023055]. As in their work, we formulate the decoding problem as a tensor network contraction and show how to contract the network efficiently by exploiting the low-depth structure. Replacing the tensor network with a so-called “tropical” tensor network, we also show how to perform minimum weight decoding. With these decoders, we are able to numerically estimate the depolarizing error threshold of finite-rate random circuit codes and show that this threshold closely matches the hashing bound even when the decoding is suboptimal.http://doi.org/10.1103/PhysRevResearch.7.013040
spellingShingle Jon Nelson
Gregory Bentsen
Steven T. Flammia
Michael J. Gullans
Fault-tolerant quantum memory using low-depth random circuit codes
Physical Review Research
title Fault-tolerant quantum memory using low-depth random circuit codes
title_full Fault-tolerant quantum memory using low-depth random circuit codes
title_fullStr Fault-tolerant quantum memory using low-depth random circuit codes
title_full_unstemmed Fault-tolerant quantum memory using low-depth random circuit codes
title_short Fault-tolerant quantum memory using low-depth random circuit codes
title_sort fault tolerant quantum memory using low depth random circuit codes
url http://doi.org/10.1103/PhysRevResearch.7.013040
work_keys_str_mv AT jonnelson faulttolerantquantummemoryusinglowdepthrandomcircuitcodes
AT gregorybentsen faulttolerantquantummemoryusinglowdepthrandomcircuitcodes
AT steventflammia faulttolerantquantummemoryusinglowdepthrandomcircuitcodes
AT michaeljgullans faulttolerantquantummemoryusinglowdepthrandomcircuitcodes