collaborators

7 papers

quant-ph2026

Parsimonious Quantum Low-Density Parity-Check Code Surgery

Andrew C. Yuan, Alexander Cowtan, Zhiyang He +2

Quantum code surgery offers a flexible, low-overhead framework for executing logical measurements within quantum error-correcting codes. It encompasses several fault-tolerant logic…

quant-ph2026

Parallel Logical Measurements via Quantum Code Surgery

Alexander Cowtan, Zhiyang He, Dominic J. Williamson +1

Quantum code surgery is a flexible and low overhead technique for performing logical measurements on quantum error-correcting codes, which generalises lattice surgery. In this work…

quant-ph2025

Extractors: QLDPC Architectures for Efficient Pauli-Based Computation

Zhiyang He, Alexander Cowtan, Dominic J. Williamson +1

In pursuit of large-scale fault-tolerant quantum computation, quantum low-density parity-check (LDPC) codes have been established as promising candidates for low-overhead memory wh…

quant-ph2025

Fast and fault-tolerant logical measurements: Auxiliary hypergraphs and transversal surgery

Alexander Cowtan, Zhiyang He, Dominic J. Williamson +1

Quantum code surgery is a promising technique to perform fault-tolerant computation on quantum low-density parity-check codes. Recent developments have significantly reduced the sp…

quant-ph2025

Homology, Hopf Algebras and Quantum Code Surgery

Alexander Cowtan

This thesis is a study of quantum error-correction codes from an algebraic perspective. We concern ourselves not only with quantum codes but also protocols to perform logical quant…

quant-ph2024

SSIP: automated surgery with quantum LDPC codes

Alexander Cowtan

We present Safe Surgery by Identifying Pushouts (SSIP), an open-source lightweight Python package for automating surgery between qubit CSS codes. SSIP is flexible: it is capable of…