Fault-Tolerant QLDPC Syndrome Measurement via LDGM Encoding
Duke Quantum Center, Duke University（杜克大学量子中心）；Department of Electrical and Computer Engineering, Duke University（杜克大学电气与计算机工程系）；Department of Mathematics and Statistics, University of South Florida（南佛罗里达大学数学与统计系）
We propose the use of certain low-density generator-matrix (LDGM) codes as syndrome measurement (SM) codes for quantum low-density parity check (QLDPC) codes. We use an efficient progressive-edge-growth-like algorithm to create LDGM SM codes with column and row weights that result in measured stabilizers that have constant weight, thus preserving the desirable properties of the underlying QLDPC code. This process allows for control over stabilizer weights and SM code distance, resulting in significantly better performance than repeated syndrome extraction and allowing for both higher distances and fewer syndrome measurements. We implement these SM codes on a distance-5 rotated surface code, and show that this procedure results in a lower probability of logical error. As syndrome measurements performed are a reasonable metric for the time a circuit takes to implement, we conclude that these LDGM codes allow for improved implementation of QLDPC codes without sacrificing the low weights of the syndrome measurements performed.
Chromatic Block-Gibbs p-Bit Decoding of QLDPC Codes
Western Digital, San Jose, CA, USA（西部数据）；Duke Quantum Center, Duke University, Durham, NC, USA（杜克大学量子中心）；Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA（杜克大学电气与计算机工程系）；Department of Mathematics, Duke University, Durham, NC, USA（杜克大学数学系）
Quantum errors are primarily detected and corrected using the measurement of syndrome information which itself is an unreliable step in practical error correction implementations. Typically, such faulty or noisy syndrome measurements are modeled as a binary measurement outcome flipped with some probability. However, the measured syndrome is in fact a discretized value of the continuous voltage or current values obtained in the physical implementation of the syndrome extraction. In this paper, we use this "soft" or analog information without the conventional discretization step to benefit the i…
Optimal Compilation of Syndrome Extraction Circuits for General Quantum LDPC Codes
Tsinghua University（清华大学）；Pengcheng Laboratory（鹏城实验室）；Key Laboratory of System Software (Chinese Academy of Sciences)（中国科学院系统软件重点实验室）；The Hong Kong University of Science and Technology（香港科技大学）；Institute of Software, Chinese Academy of Sciences（中国科学院软件研究所）
Simple, Efficient, and Generic Post-Selection Decoding for qLDPC Codes
Graduate School of China Academy of Engineering Physics（中国工程物理研究院研究生院）；International Center for Elementary Particle Physics, University of Tokyo（东京大学基础粒子物理国际中心）；Department of Applied Physics, University of Tokyo（东京大学应用物理系）
We study the performance of medium-length quantum LDPC (QLDPC) codes in the depolarizing channel. Only degenerate codes with the maximal stabilizer weight much smaller than their minimum distance are considered. It is shown that with the help of OSD-like post-processing the performance of the standard belief propagation (BP) decoder on many QLDPC codes can be improved by several orders of magnitude. Using this new BP-OSD decoder we study the performance of several known classes of degenerate QLDPC codes including hypergraph product codes, hyperbicycle codes, homological product codes, and Haah…
Adaptive decoding of quantum LDPC codes through decoder disagreement
Centre for Computational Science, University College London（计算科学中心，伦敦大学学院）；Advanced Research Computing Centre, University College London（高级研究计算中心，伦敦大学学院）
Iterative decoders for finite length quantum low-density parity-check (QLDPC) codes are attractive because their hardware complexity scales only linearly with the number of physical qubits. However, they are impacted by short cycles, detrimental graphical configurations known as trapping sets (TSs) present in a code graph as well as symmetric degeneracy of errors. These factors significantly degrade the decoder decoding probability performance and cause so-called error floor. In this paper, we establish a systematic methodology by which one can identify and classify quantum trapping sets (QTSs…
Yau Mathematical Sciences Center, Tsinghua University（清华大学丘成桐数学科学中心）；State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University（清华大学物理系低维量子物理国家重点实验室）；Joint Center for Quantum Information and Computer Science, University of Maryland（马里兰大学量子信息与计算机联合中心）；Shanghai Institute for Mathematics and Interdisciplinary Sciences (SIMIS)（上海数学与交叉学科研究院）
Demonstration of low-overhead quantum error correction codes
Zhejiang University（浙江大学）；Shanghai Qi Zhi Institute（上海人工智能实验室）；Tsinghua University（清华大学）；Harvard University（哈佛大学）；Xi'an Jiaotong University（西安交通大学）；Institute of Physics, Polish Academy of Sciences（波兰科学院物理研究所）；Hefei National Laboratory（合肥国家实验室）
Optimizing compilation of error correction codes for 2xN quantum dot arrays and its NP-hardness
Manning College of Information and Computer Sciences, University of Massachusetts Amherst（马萨诸塞大学阿默斯特分校曼宁信息科学与计算机学院）；QuTech and Kavli Institute of Nanoscience, Delft University of Technology（代尔夫特理工大学量子技术与卡弗里纳米科学研究所）
Constant-Time Surgery on 2D Hypergraph Product Codes with Near-Constant Space Overhead
IBM Quantum, IBM T. J. Watson Research Center（IBM量子，IBM托马斯·J·沃森研究中心）；Department of Physics, Yale University（耶鲁大学物理系）；Yale Quantum Institute, Yale University（耶鲁大学量子研究所）；Department of Mathematics, Massachusetts Institute of Technology（麻省理工学院数学系）
Quantum error correction and fault tolerance: A comprehensive tutorial
Joint Center for Quantum Information and Computer Science, NIST/University of Maryland（量子信息与计算机联合中心，美国国家标准与技术研究院/马里兰大学）；Department of Physics, University of Maryland（马里兰大学物理系）；Joint Quantum Institute, NIST/University of Maryland（量子联合研究所，美国国家标准与技术研究院/马里兰大学）；Centre for Quantum Technologies, National University of Singapore（新加坡国立大学量子技术中心）；Nanyang Quantum Hub, School of Physical and Mathematical Sciences, Nanyang Technological University（南洋理工大学理学院南洋量子枢纽）；Quantum Research Center, Technology Innovation Institute（技术创新研究所量子研究中心）；Department of Computer Science and Institute for Advanced Co（计算机科学系与高级合作研究所）
Quantum Compiler Design for Fault-Tolerant Quantum Computing
QudeLeap Research；The Hong Kong University of Science and Technology (Guangzhou)（香港科技大学（广州））；The Hong Kong University of Science and Technology（香港科技大学）；Shanghai Jiao Tong University（上海交通大学）；Hangzhou MatriQ Computing Co., Ltd（杭州矩阵量子计算有限公司）；Atomqubic Quantum Technology Co., Ltd（上海原子立方量子科技有限公司）；State Key Laboratory of Quantum Optics Technologies and Devices, and Institute of Opto-Electronics, Shanxi University（山西大学光电研究所及量子光学技术与器件国家重点实验室）；CAS Cold Atom Technology (Wuhan) Co., Ltd.（中科院冷原子技术（武汉）有限公司）；Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area（粤港澳大湾区量子科学中心）
Accelerating A*-Based Algorithms for Decoding Quantum Low-Density Parity-Check Codes
School of Electrical and Electronic Engineering, University College Dublin（都柏林大学学院电气与电子工程学院）；Department of Computer Architecture and Automatics, Complutense University of Madrid（马德里康普顿斯大学计算机体系结构与自动系）
