Computing with many encoded logical qubits beyond break-even
Quantinuum
Shival Dasu, Matthew DeCross, Andrew Y. Guo, Ali Lavasani, Jan Behrends, Asmae Benhemou, Yi-Hsiang Chen, Karl Mayer, Chris N. Self, Selwyn Simsek, Basudha Sriva… 展开作者
Shival Dasu, Matthew DeCross, Andrew Y. Guo, Ali Lavasani, Jan Behrends, Asmae Benhemou, Yi-Hsiang Chen, Karl Mayer, Chris N. Self, Selwyn Simsek, Basudha Srivastava, M. S. Allman, Jake Arkinstall, Justin G. Bohnet, Nathaniel Q. Burdick, J. P. Campora, Alex Chernoguzov, Samuel F. Cooper, Robert D. Delaney, Joan M. Dreiling, Brian Estey, Caroline Figgatt, Cameron Foltz, John P. Gaebler, Alex Hall, Craig A. Holliman, Ali A. Husain, Akhil Isanaka, Colin J. Kennedy, Yuga Kodama, Nikhil Kotibhaskar, Nathan K. Lysne, Ivaylo S. Madjarov, Michael Mills, Alistair R. Milne, Brian Neyenhuis, Annie J. Park, Anthony Ransford, Adam P. Reed, Steven J. Sanders, Charles H. Baldwin, David Hayes, Ben Criger, Andrew C. Potter, David Amaro
High-rate quantum error correcting (QEC) codes encode many logical qubits in a given number of physical qubits, making them promising candidates for quantum computation. Implementing high-rate codes at a scale that both frustrates classical computing and improves performance by encoding requires both high fidelity gates and long-range qubit connectivity -- both of which are offered by trapped-ion quantum computers. Here, we demonstrate computations that outperform their unencoded counterparts in the high-rate $[[ k+2,\, k,\, 2 ]]$ iceberg quantum error detecting (QED) and $[[ (k_2 + 2)(k_1 + 2),\, k_2k_1,\, 4 ]]$ two-level concatenated iceberg QEC codes, using the 98-qubit Quantinuum Helios trapped-ion quantum processor. Utilizing new gadgets for encoded operations, we realize this "beyond break-even" performance with reasonable postselection rates across a range of fault-tolerant (FT) and partially-fault-tolerant (pFT) component and application benchmarks with between $48$ and $94$ logical qubits. These benchmarks include FT state preparation and measurement, QEC cycle benchmarking, logical gate benchmarking, GHZ state preparation, and a pFT quantum simulation of the three-dimensional $XY$ model of quantum magnetism. Additionally, we illustrate that postselection rates can be suppressed by increasing the code distance via concatenation. Our results represent state-of-the-art logical component and state fidelities and provide evidence that high-rate QED/QEC codes are viable on contemporary quantum computers for near-term beyond-classical-scale computation.
Correlation-Assisted Odd-Parity Encoded Gates in Coupled Fluxonium Qubits under Non-Markovian TLS Noise
School of Physics, Hangzhou Dianzi University（杭州电子科技大学物理学院）；State Key Laboratory of Quantum Optics Technologies and Devices, Shanxi University（山西大学量子光学技术与器件国家重点实验室）；Zhejiang Key Laboratory of Quantum State Control and Optical Field Manipulation, Hangzhou Dianzi University（杭州电子科技大学量子态调控与光场操纵浙江省重点实验室）
Suppression of Universal Errors in DFS-Encoded Superconducting Geometric Logical \emph{T} Gate
School of Physics and Astronomy, Anqing Normal University（安庆师范大学物理与天文学院）；School of Electronic Information and Integrated Circuits, Anqing Normal University（安庆师范大学电子信息与集成电路学院）；School of Electrical and Photoelectronic Engineering, West Anhui University（皖西大学电气与光电工程学院）
Enhanced analogue quantum computation with a logically-encoded XX gadget
University College London（伦敦大学学院）；Indian Institute of Technology, Bhubaneswar（布巴内斯瓦尔印度理工学院）；Jülich Supercomputing Centre, Institute for Advanced Simulation, Forschungszentrum Jülich（于利希超级计算中心，先进模拟研究所，于利希研究中心）；Universität zu Köln（科隆大学）
Generation of frequency-bin-encoded dual-rail cluster states via time-frequency multiplexing of microwave photonic qubits
RIKEN Center for Quantum Computing (RQC)（理化学研究所量子计算中心）；Department of Applied Physics, Graduate School of Engineering, The University of Tokyo（东京大学大学院工学系研究科应用物理系）；Department of Applied Physics, Stanford University（斯坦福大学应用物理系）
Quantum error correction of a qubit encoded in grid states of an oscillator
量子比特在非局部编码时对噪声更鲁棒。在这种编码中，影响底层物理系统的错误可以在它们破坏编码信息之前被检测和纠正。在2001年，Gottesman，Kitaev and Preskill（GKP）提出了一个这样的量子比特的硬件有效实例，它在单个振荡器的相空间中离域。然而，实现在保留编码信息的同时揭示振荡器的错误综合征的测量已被实验证明具有挑战性：迄今为止唯一的实现依赖于后选择，这与量子纠错（QEC）不兼容。我们的实验的新颖之处恰恰在于它实现了超导微波腔的这些非破坏性误差综合征测量。我们设计并实现了一个原始的反馈协议，将这样的测量准备正方形和六边形的GKP代码状态。然后，我们展示了一个编码的量子比特的QEC与前所未有的抑制所有逻辑错误，在定量协议与理论估计的基础上测得的不完善的实验。我们的协议是适用于其他连续变量系统，并与以前的实现QEC相比，可以减轻各种各样的噪声过程产生的所有逻辑错误，并打开一条通往容错量子计算的道路。
Converting qubit relaxation into erasures with a single fluxonium
Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area（粤港澳大湾区量子科学中心）；Beijing Academy of Quantum Information Sciences（北京量子信息科学研究院）；Hefei National Laboratory（合肥国家实验室）
IonQ Inc.（IonQ公司）；QuICS, NIST/University of Maryland（量子信息与计算科学研究所，美国国家标准与技术研究院/马里兰大学）；UMIACS, University of Maryland（统一信息管理与计算系统研究所，马里兰大学）；Quantum Research Center, Technology Innovation Institute（量子研究中心，技术创新研究所）；Centre for Quantum Technologies, National University of Singapore（量子技术中心，新加坡国立大学）；Nanyang Quantum Hub, School of Physical and Mathematical Sciences, Nanyang Technological University（南洋量子枢纽，物理与数学科学学院，南洋理工大学）
Demonstration of High-Fidelity Entangled Logical Qubits using Transmons
University of Southern California（南加州大学）；Quantum Elements, Inc.（量子元素公司）；IBM Quantum（IBM量子）；RWTH Aachen University（亚琛工业大学）；Forschungszentrum Jülich（于利希研究中心）
