1
|
Ma X, Zhang G, Wu F, Bao F, Chang X, Chen J, Deng H, Gao R, Gao X, Hu L, Ji H, Ku HS, Lu K, Ma L, Mao L, Song Z, Sun H, Tang C, Wang F, Wang H, Wang T, Xia T, Ying M, Zhan H, Zhou T, Zhu M, Zhu Q, Shi Y, Zhao HH, Deng C. Native Approach to Controlled-Z Gates in Inductively Coupled Fluxonium Qubits. Phys Rev Lett 2024; 132:060602. [PMID: 38394561 DOI: 10.1103/physrevlett.132.060602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 01/08/2024] [Indexed: 02/25/2024]
Abstract
The fluxonium qubits have emerged as a promising platform for gate-based quantum information processing. However, their extraordinary protection against charge fluctuations comes at a cost: when coupled capacitively, the qubit-qubit interactions are restricted to XX interactions. Consequently, effective ZZ or XZ interactions are only constructed either by temporarily populating higher-energy states, or by exploiting perturbative effects under microwave driving. Instead, we propose and demonstrate an inductive coupling scheme, which offers a wide selection of native qubit-qubit interactions for fluxonium. In particular, we leverage a built-in, flux-controlled ZZ interaction to perform qubit entanglement. To combat the increased flux-noise-induced dephasing away from the flux-insensitive position, we use a continuous version of the dynamical decoupling scheme to perform noise filtering. Combining these, we demonstrate a 20 ns controlled-z gate with a mean fidelity of 99.53%. More than confirming the efficacy of our gate scheme, this high-fidelity result also reveals a promising but rarely explored parameter space uniquely suitable for gate operations between fluxonium qubits.
Collapse
Affiliation(s)
- Xizheng Ma
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Gengyan Zhang
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Feng Wu
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Feng Bao
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Xu Chang
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Jianjun Chen
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Hao Deng
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Ran Gao
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Xun Gao
- DAMO Quantum Laboratory, Alibaba Group USA, Bellevue, Washington 98004, USA
| | - Lijuan Hu
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Honghong Ji
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Hsiang-Sheng Ku
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Kannan Lu
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Lu Ma
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Liyong Mao
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Zhijun Song
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Hantao Sun
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Chengchun Tang
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Fei Wang
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Hongcheng Wang
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Tenghui Wang
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Tian Xia
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Make Ying
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Huijuan Zhan
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Tao Zhou
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Mengyu Zhu
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Qingbin Zhu
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| | - Yaoyun Shi
- DAMO Quantum Laboratory, Alibaba Group USA, Bellevue, Washington 98004, USA
| | - Hui-Hai Zhao
- DAMO Quantum Laboratory, Alibaba Group, Beijing 100102, China
| | - Chunqing Deng
- DAMO Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, China
| |
Collapse
|
2
|
Scholl P, Shaw AL, Tsai RBS, Finkelstein R, Choi J, Endres M. Erasure conversion in a high-fidelity Rydberg quantum simulator. Nature 2023; 622:273-278. [PMID: 37821592 PMCID: PMC10567575 DOI: 10.1038/s41586-023-06516-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/03/2023] [Indexed: 10/13/2023]
Abstract
Minimizing and understanding errors is critical for quantum science, both in noisy intermediate scale quantum (NISQ) devices1 and for the quest towards fault-tolerant quantum computation2,3. Rydberg arrays have emerged as a prominent platform in this context4 with impressive system sizes5,6 and proposals suggesting how error-correction thresholds could be significantly improved by detecting leakage errors with single-atom resolution7,8, a form of erasure error conversion9-12. However, two-qubit entanglement fidelities in Rydberg atom arrays13,14 have lagged behind competitors15,16 and this type of erasure conversion is yet to be realized for matter-based qubits in general. Here we demonstrate both erasure conversion and high-fidelity Bell state generation using a Rydberg quantum simulator5,6,17,18. When excising data with erasure errors observed via fast imaging of alkaline-earth atoms19-22, we achieve a Bell state fidelity of [Formula: see text], which improves to [Formula: see text] when correcting for remaining state-preparation errors. We further apply erasure conversion in a quantum simulation experiment for quasi-adiabatic preparation of long-range order across a quantum phase transition, and reveal the otherwise hidden impact of these errors on the simulation outcome. Our work demonstrates the capability for Rydberg-based entanglement to reach fidelities in the 0.999 regime, with higher fidelities a question of technical improvements, and shows how erasure conversion can be utilized in NISQ devices. These techniques could be translated directly to quantum-error-correction codes with the addition of long-lived qubits7,22-24.
Collapse
Affiliation(s)
- Pascal Scholl
- California Institute of Technology, Pasadena, CA, USA
| | - Adam L Shaw
- California Institute of Technology, Pasadena, CA, USA
| | | | | | - Joonhee Choi
- California Institute of Technology, Pasadena, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Manuel Endres
- California Institute of Technology, Pasadena, CA, USA.
| |
Collapse
|
3
|
Pan X, Lu Z, Wang W, Hua Z, Xu Y, Li W, Cai W, Li X, Wang H, Song YP, Zou CL, Deng DL, Sun L. Deep quantum neural networks on a superconducting processor. Nat Commun 2023; 14:4006. [PMID: 37414812 DOI: 10.1038/s41467-023-39785-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 06/29/2023] [Indexed: 07/08/2023] Open
Abstract
Deep learning and quantum computing have achieved dramatic progresses in recent years. The interplay between these two fast-growing fields gives rise to a new research frontier of quantum machine learning. In this work, we report an experimental demonstration of training deep quantum neural networks via the backpropagation algorithm with a six-qubit programmable superconducting processor. We experimentally perform the forward process of the backpropagation algorithm and classically simulate the backward process. In particular, we show that three-layer deep quantum neural networks can be trained efficiently to learn two-qubit quantum channels with a mean fidelity up to 96.0% and the ground state energy of molecular hydrogen with an accuracy up to 93.3% compared to the theoretical value. In addition, six-layer deep quantum neural networks can be trained in a similar fashion to achieve a mean fidelity up to 94.8% for learning single-qubit quantum channels. Our experimental results indicate that the number of coherent qubits required to maintain does not scale with the depth of the deep quantum neural network, thus providing a valuable guide for quantum machine learning applications with both near-term and future quantum devices.
Collapse
Affiliation(s)
- Xiaoxuan Pan
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China
| | - Zhide Lu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China
| | - Weiting Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China
| | - Ziyue Hua
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China
| | - Yifang Xu
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China
| | - Weikang Li
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China
| | - Weizhou Cai
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China
| | - Xuegang Li
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China
| | - Haiyan Wang
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China
| | - Yi-Pu Song
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China
| | - Chang-Ling Zou
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui, 230026, China
- Hefei National Laboratory, Hefei, 230088, China
| | - Dong-Ling Deng
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China.
- Hefei National Laboratory, Hefei, 230088, China.
- Shanghai Qi Zhi Institute, No. 701 Yunjin Road, Xuhui District, Shanghai, 200232, China.
| | - Luyan Sun
- Center for Quantum Information, Institute for Interdisciplinary Information Sciences, Tsinghua University, Beijing, 100084, China.
- Hefei National Laboratory, Hefei, 230088, China.
| |
Collapse
|
4
|
Marques JF, Ali H, Varbanov BM, Finkel M, Veen HM, van der Meer SLM, Valles-Sanclemente S, Muthusubramanian N, Beekman M, Haider N, Terhal BM, DiCarlo L. All-Microwave Leakage Reduction Units for Quantum Error Correction with Superconducting Transmon Qubits. Phys Rev Lett 2023; 130:250602. [PMID: 37418741 DOI: 10.1103/physrevlett.130.250602] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/24/2023] [Indexed: 07/09/2023]
Abstract
Minimizing leakage from computational states is a challenge when using many-level systems like superconducting quantum circuits as qubits. We realize and extend the quantum-hardware-efficient, all-microwave leakage reduction unit (LRU) for transmons in a circuit QED architecture proposed by Battistel et al. This LRU effectively reduces leakage in the second- and third-excited transmon states with up to 99% efficacy in 220 ns, with minimum impact on the qubit subspace. As a first application in the context of quantum error correction, we show how multiple simultaneous LRUs can reduce the error detection rate and suppress leakage buildup within 1% in data and ancilla qubits over 50 cycles of a weight-2 stabilizer measurement.
Collapse
Affiliation(s)
- J F Marques
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - H Ali
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - B M Varbanov
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - M Finkel
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - H M Veen
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - S L M van der Meer
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - S Valles-Sanclemente
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - N Muthusubramanian
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - M Beekman
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- Netherlands Organisation for Applied Scientific Research (TNO), P.O. Box 96864, 2509 JG The Hague, Netherlands
| | - N Haider
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- Netherlands Organisation for Applied Scientific Research (TNO), P.O. Box 96864, 2509 JG The Hague, Netherlands
| | - B M Terhal
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- EEMCS Department, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| | - L DiCarlo
- QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft, Netherlands
| |
Collapse
|
5
|
Abad T, Fernández-Pendás J, Frisk Kockum A, Johansson G. Universal Fidelity Reduction of Quantum Operations from Weak Dissipation. Phys Rev Lett 2022; 129:150504. [PMID: 36269966 DOI: 10.1103/physrevlett.129.150504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Quantum information processing is in real systems often limited by dissipation, stemming from remaining uncontrolled interaction with microscopic degrees of freedom. Given recent experimental progress, we consider weak dissipation, resulting in a small error probability per operation. Here, we find a simple formula for the fidelity reduction of any desired quantum operation, where the ideal evolution is confined to the computational subspace. Interestingly, this reduction is independent of the specific operation; it depends only on the operation time and the dissipation. Using our formula, we investigate the situation where dissipation in different parts of the system has correlations, which is detrimental for the successful application of quantum error correction. Surprisingly, we find that a large class of correlations gives the same fidelity reduction as uncorrelated dissipation of similar strength.
Collapse
Affiliation(s)
- Tahereh Abad
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Jorge Fernández-Pendás
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Anton Frisk Kockum
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Göran Johansson
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| |
Collapse
|
6
|
Bao F, Deng H, Ding D, Gao R, Gao X, Huang C, Jiang X, Ku HS, Li Z, Ma X, Ni X, Qin J, Song Z, Sun H, Tang C, Wang T, Wu F, Xia T, Yu W, Zhang F, Zhang G, Zhang X, Zhou J, Zhu X, Shi Y, Chen J, Zhao HH, Deng C. Fluxonium: An Alternative Qubit Platform for High-Fidelity Operations. Phys Rev Lett 2022; 129:010502. [PMID: 35841558 DOI: 10.1103/physrevlett.129.010502] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Superconducting qubits provide a promising path toward building large-scale quantum computers. The simple and robust transmon qubit has been the leading platform, achieving multiple milestones. However, fault-tolerant quantum computing calls for qubit operations at error rates significantly lower than those exhibited in the state of the art. Consequently, alternative superconducting qubits with better error protection have attracted increasing interest. Among them, fluxonium is a particularly promising candidate, featuring large anharmonicity and long coherence times. Here, we engineer a fluxonium-based quantum processor that integrates high qubit coherence, fast frequency tunability, and individual-qubit addressability for reset, readout, and gates. With simple and fast gate schemes, we achieve an average single-qubit gate fidelity of 99.97% and a two-qubit gate fidelity of up to 99.72%. This performance is comparable to the highest values reported in the literature of superconducting circuits. Thus our work, within the realm of superconducting qubits, reveals an alternative qubit platform that is competitive with the transmon system.
Collapse
Affiliation(s)
- Feng Bao
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Hao Deng
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Dawei Ding
- Alibaba Quantum Laboratory, Alibaba Group USA, Bellevue, Washington, D.C. 98004, USA
| | - Ran Gao
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Xun Gao
- Alibaba Quantum Laboratory, Alibaba Group USA, Bellevue, Washington, D.C. 98004, USA
| | - Cupjin Huang
- Alibaba Quantum Laboratory, Alibaba Group USA, Bellevue, Washington, D.C. 98004, USA
| | - Xun Jiang
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Hsiang-Sheng Ku
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Zhisheng Li
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Xizheng Ma
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Xiaotong Ni
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Jin Qin
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Zhijun Song
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Hantao Sun
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Chengchun Tang
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Tenghui Wang
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Feng Wu
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Tian Xia
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Wenlong Yu
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Fang Zhang
- Alibaba Quantum Laboratory, Alibaba Group USA, Bellevue, Washington, D.C. 98004, USA
| | - Gengyan Zhang
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Xiaohang Zhang
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Jingwei Zhou
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Xing Zhu
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| | - Yaoyun Shi
- Alibaba Quantum Laboratory, Alibaba Group USA, Bellevue, Washington, D.C. 98004, USA
| | - Jianxin Chen
- Alibaba Quantum Laboratory, Alibaba Group USA, Bellevue, Washington, D.C. 98004, USA
| | - Hui-Hai Zhao
- Alibaba Quantum Laboratory, Alibaba Group, Beijing 100102, People's Republic of China
| | - Chunqing Deng
- Alibaba Quantum Laboratory, Alibaba Group, Hangzhou, Zhejiang 311121, People's Republic of China
| |
Collapse
|
7
|
Krinner S, Lacroix N, Remm A, Di Paolo A, Genois E, Leroux C, Hellings C, Lazar S, Swiadek F, Herrmann J, Norris GJ, Andersen CK, Müller M, Blais A, Eichler C, Wallraff A. Realizing repeated quantum error correction in a distance-three surface code. Nature 2022; 605:669-674. [PMID: 35614249 DOI: 10.1038/s41586-022-04566-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/09/2022] [Indexed: 11/09/2022]
Abstract
Quantum computers hold the promise of solving computational problems that are intractable using conventional methods1. For fault-tolerant operation, quantum computers must correct errors occurring owing to unavoidable decoherence and limited control accuracy2. Here we demonstrate quantum error correction using the surface code, which is known for its exceptionally high tolerance to errors3-6. Using 17 physical qubits in a superconducting circuit, we encode quantum information in a distance-three logical qubit, building on recent distance-two error-detection experiments7-9. In an error-correction cycle taking only 1.1 μs, we demonstrate the preservation of four cardinal states of the logical qubit. Repeatedly executing the cycle, we measure and decode both bit-flip and phase-flip error syndromes using a minimum-weight perfect-matching algorithm in an error-model-free approach and apply corrections in post-processing. We find a low logical error probability of 3% per cycle when rejecting experimental runs in which leakage is detected. The measured characteristics of our device agree well with a numerical model. Our demonstration of repeated, fast and high-performance quantum error-correction cycles, together with recent advances in ion traps10, support our understanding that fault-tolerant quantum computation will be practically realizable.
Collapse
Affiliation(s)
| | | | - Ants Remm
- Department of Physics, ETH Zurich, Zurich, Switzerland
| | - Agustin Di Paolo
- Institut Quantique, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Elie Genois
- Institut Quantique, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Catherine Leroux
- Institut Quantique, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | | | | | | | | | | | - Christian Kraglund Andersen
- Department of Physics, ETH Zurich, Zurich, Switzerland.,QuTech and Kavli Institute for Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Markus Müller
- Institute for Quantum Information, RWTH Aachen University, Aachen, Germany.,Peter Grünberg Institute, Theoretical Nanoelectronics, Forschungszentrum Jülich, Jülich, Germany
| | - Alexandre Blais
- Institut Quantique, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Canadian Institute for Advanced Research, Toronto, Ontario, Canada
| | | | - Andreas Wallraff
- Department of Physics, ETH Zurich, Zurich, Switzerland.,Quantum Center, ETH Zurich, Zurich, Switzerland
| |
Collapse
|
8
|
Mitchell BK, Naik RK, Morvan A, Hashim A, Kreikebaum JM, Marinelli B, Lavrijsen W, Nowrouzi K, Santiago DI, Siddiqi I. Hardware-Efficient Microwave-Activated Tunable Coupling between Superconducting Qubits. Phys Rev Lett 2021; 127:200502. [PMID: 34860047 DOI: 10.1103/physrevlett.127.200502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
Generating high-fidelity, tunable entanglement between qubits is crucial for realizing gate-based quantum computation. In superconducting circuits, tunable interactions are often implemented using flux-tunable qubits or coupling elements, adding control complexity and noise sources. Here, we realize a tunable ZZ interaction between two transmon qubits with fixed frequencies and fixed coupling, induced by driving both transmons off resonantly. We show tunable coupling over 1 order of magnitude larger than the static coupling, and change the sign of the interaction, enabling cancellation of the idle coupling. Further, this interaction is amenable to large quantum processors: the drive frequency can be flexibly chosen to avoid spurious transitions, and because both transmons are driven, it is resilient to microwave cross talk. We apply this interaction to implement a controlled phase (CZ) gate with a gate fidelity of 99.43(1)% as measured by cycle benchmarking, and we find the fidelity is limited by incoherent errors.
Collapse
Affiliation(s)
- Bradley K Mitchell
- Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, California 94720, USA
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ravi K Naik
- Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, California 94720, USA
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Alexis Morvan
- Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, California 94720, USA
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Akel Hashim
- Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, California 94720, USA
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - John Mark Kreikebaum
- Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Brian Marinelli
- Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, California 94720, USA
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Wim Lavrijsen
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Kasra Nowrouzi
- Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, California 94720, USA
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - David I Santiago
- Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, California 94720, USA
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Irfan Siddiqi
- Quantum Nanoelectronics Laboratory, University of California, Berkeley, Berkeley, California 94720, USA
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| |
Collapse
|
9
|
Stehlik J, Zajac DM, Underwood DL, Phung T, Blair J, Carnevale S, Klaus D, Keefe GA, Carniol A, Kumph M, Steffen M, Dial OE. Tunable Coupling Architecture for Fixed-Frequency Transmon Superconducting Qubits. Phys Rev Lett 2021; 127:080505. [PMID: 34477428 DOI: 10.1103/physrevlett.127.080505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Implementation of high-fidelity 2-qubit operations is a key ingredient for scalable quantum error correction. In superconducting qubit architectures, tunable buses have been explored as a means to higher-fidelity gates. However, these buses introduce new pathways for leakage. Here we present a modified tunable bus architecture appropriate for fixed-frequency qubits in which the adiabaticity restrictions on gate speed are reduced. We characterize this coupler on a range of 2-qubit devices, achieving a maximum gate fidelity of 99.85%. We further show the calibration is stable over one day.
Collapse
Affiliation(s)
- J Stehlik
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - D M Zajac
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - D L Underwood
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - T Phung
- IBM Quantum, IBM Almaden Research Center, San Jose, California 95120, USA
| | - J Blair
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - S Carnevale
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - D Klaus
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - G A Keefe
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - A Carniol
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - M Kumph
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - Matthias Steffen
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| | - O E Dial
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA
| |
Collapse
|