Logical qubits can be protected against environmental noise by encoding them into a highly entangled state of many physical qubits and actively intervening in the dynamics with stabilizer measurements. In this work, we numerically optimize the rate of these interventions: the number of stabilizer measurement rounds for a logical qubit encoded in a surface code patch and idling for a given time. We model the environmental noise on the circuit level, including gate errors, readout errors, amplitude and phase damping. We find, qualitatively, that the optimal number of stabilizer measurement rounds is getting smaller for better qubits and getting larger for better gates or larger code sizes. We discuss the implications of our results to some of the leading architectures, superconducting qubits, and neutral atoms.
We study variants of Shor's code that are adept at handling single-axis correlated idling errors, which are commonly observed in many quantum systems. By using the repetition code structure of the Shor's code basis states, we calculate the logical channel applied to the encoded information when subjected to coherent and correlated single qubit idling errors, followed by stabilizer measurement. Changing the signs of the stabilizer generators allows us to change how the coherent errors interfere, leading to a quantum error correcting code which performs as well as a classical repetition code of …
Unitary fault-tolerant encoding of Pauli states in surface codes
Institute for Theoretical Nanoelectronics (PGI-2), Forschungszentrum Jülich（于利希研究中心）；Institute for Quantum Information, RWTH Aachen University（亚琛工业大学）；Max Planck Institute for the Science of Light（马克斯·普朗克光科学研究所）；School of Physics and Astronomy, Monash University（蒙纳士大学）；NVIDIA Corporation（英伟达公司）；Department of Physics, Friedrich-Alexander Universität Erlangen-Nürnberg（埃尔朗根-纽伦堡大学）
Freie Universität Berlin（柏林自由大学）；University College London（伦敦大学学院）；Google Quantum AI（谷歌量子人工智能）；IBM Quantum, T. J. Watson Research Center（IBM量子，T.J.沃森研究中心）；IBM Denmark（IBM丹麦）
3D Stacked Surface-Code Architecture for Measurement-Free Fault-Tolerant Quantum Error Correction
School of Electrical Engineering, Korea University（韩国大学电气工程学院）；Quantum Network Research center, Korea Institute of Science and Technology Information（韩国科学技术信息研究院量子网络研究中心）
Fault-tolerant quantum computation with static atomic buses
University of Strasbourg（斯特拉斯堡大学）；CNRS（法国国家科学研究中心）；CESQ（量子化学中心）；ISIS（结构与成像研究所）；Department of Physics, University of Wisconsin-Madison（威斯康星大学麦迪逊分校物理系）；QPerfect SAS（QPerfect公司）；Institut Universitaire de France (IUF)（法兰西学院）；Infleqtion（Infleqtion公司）
In this work we establish lower bounds on the size of Clifford circuits that measure a family of commuting Pauli operators. Our bounds depend on the interplay between a pair of graphs: the Tanner graph of the set of measured Pauli operators, and the connectivity graph which represents the qubit connections required to implement the circuit. For local-expander quantum codes, which are promising for low-overhead quantum error correction, we prove that any syndrome extraction circuit implemented with local Clifford gates in a 2D square patch of $N$ qubits has depth at least $Ω(n/\sqrt{N})$ where …
Dense packing of the surface code: code deformation procedures and hook-error-avoiding gate scheduling
Graduate School of Science and Technology, Keio University（庆应义塾大学理工学研究科）；Graduate School of Media Design, Keio University（庆应义塾大学媒体设计研究科）；Department of Physics & Astronomy, University College London（伦敦大学学院物理与天文系）；Faculty of Science and Technology, Keio University（庆应义塾大学理工学部）
Lattice surgery for near-term experimental logical qubit entanglement creation in planar architectures
Institute for Theoretical Nanoelectronics (PGI-2), Forschungszentrum Jülich（于利希研究中心理论纳米电子学研究所）；Institute for Quantum Information, RWTH Aachen University（亚琛工业大学量子信息研究所）；Department of Physics, ETH Zurich（苏黎世联邦理工学院物理系）；ETH Zurich - PSI Quantum Computing Hub, Paul Scherrer Institute（保罗谢勒研究所苏黎世联邦理工学院-PSI量子计算中心）；Quantum Center, ETH Zurich（苏黎世联邦理工学院量子中心）
Distributed estimation of many-body Hamiltonians via punctured surface code
The Chinese University of Hong Kong（香港中文大学）；Hong Kong University of Science and Technology（香港科技大学）；Perimeter Institute for Theoretical Physics（理论物理前沿研究所）；University of Waterloo（滑铁卢大学）
Scaling and logic in the color code on a superconducting quantum processor
Google Research（谷歌研究）；Department of Physics, ETH Zurich（苏黎世联邦理工学院物理系）；Google DeepMind（谷歌DeepMind）；Department of Electrical and Computer Engineering, University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校电气与计算机工程系）；Department of Physics, University of Connecticut（康涅狄格大学物理系）；Department of Computer Science, University of California, Santa Barbara（加州大学圣塔芭芭拉分校计算机科学系）；Research Laboratory of Electronics, Massachusetts Institute of Technology（麻省理工学院电子学研究实验室）；Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology（麻省理工学院电气与计算机工程系）；Department of Physics, Massachusetts Institute of Technology（麻省理工学院物理系）
