npj Quantum Information最新文献_第7页

A hybrid framework for estimating nonlinear functions of quantum states 估算量子态非线性函数的混合框架

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-06-21 DOI: 10.1038/s41534-024-00846-5

You Zhou, Zhenhuan Liu

引用次数: 0

Mapping of valley splitting by conveyor-mode spin-coherent electron shuttling 通过传送带模式自旋相干电子穿梭绘制山谷分裂图

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-06-19 DOI: 10.1038/s41534-024-00852-7

Mats Volmer, Tom Struck, Arnau Sala, Bingjie Chen, Max Oberländer, Tobias Offermann, Ran Xue, Lino Visser, Jhih-Sian Tu, Stefan Trellenkamp, Łukasz Cywiński, Hendrik Bluhm, Lars R. Schreiber

{"title":"Mapping of valley splitting by conveyor-mode spin-coherent electron shuttling","authors":"Mats Volmer, Tom Struck, Arnau Sala, Bingjie Chen, Max Oberländer, Tobias Offermann, Ran Xue, Lino Visser, Jhih-Sian Tu, Stefan Trellenkamp, Łukasz Cywiński, Hendrik Bluhm, Lars R. Schreiber","doi":"10.1038/s41534-024-00852-7","DOIUrl":"https://doi.org/10.1038/s41534-024-00852-7","url":null,"abstract":"In Si/SiGe heterostructures, the low-lying excited valley state seriously limits the operability and scalability of electron spin qubits. For characterizing and understanding the local variations in valley splitting, fast probing methods with high spatial and energy resolution are lacking. Leveraging the spatial control granted by conveyor-mode spin-coherent electron shuttling, we introduce a method for two-dimensional mapping of the local valley splitting by detecting magnetic field-dependent anticrossings of ground and excited valley states using entangled electron spin-pairs as a probe. The method has sub-μeV energy accuracy and a nanometer lateral resolution. The histogram of valley splittings spanning a large area of 210 nm by 18 nm matches well with statistics obtained by the established but time-consuming magnetospectroscopy method. For the specific heterostructure, we find a nearly Gaussian distribution of valley splittings and a correlation length similar to the quantum dot size. Our mapping method may become a valuable tool for engineering Si/SiGe heterostructures for scalable quantum computing.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"54 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141425322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantification of entanglement and coherence with purity detection 利用纯度检测量化纠缠和相干性

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-06-15 DOI: 10.1038/s41534-024-00857-2

Ting Zhang, Graeme Smith, John A. Smolin, Lu Liu, Xu-Jie Peng, Qi Zhao, Davide Girolami, Xiongfeng Ma, Xiao Yuan, He Lu

{"title":"Quantification of entanglement and coherence with purity detection","authors":"Ting Zhang, Graeme Smith, John A. Smolin, Lu Liu, Xu-Jie Peng, Qi Zhao, Davide Girolami, Xiongfeng Ma, Xiao Yuan, He Lu","doi":"10.1038/s41534-024-00857-2","DOIUrl":"https://doi.org/10.1038/s41534-024-00857-2","url":null,"abstract":"Entanglement and coherence are fundamental properties of quantum systems, promising to power near-future quantum technologies, such as quantum computation, quantum communication, and quantum metrology. Yet, their quantification, rather than mere detection, generally requires reconstructing the spectrum of quantum states, i.e., experimentally challenging measurement sets that increase exponentially with the system size. Here, we demonstrate quantitative bounds to operationally useful entanglement and coherence that are universally valid, analytically computable, and experimentally friendly. Specifically, our main theoretical results are lower and upper bounds to the coherent information and the relative entropy of coherence in terms of local and global purities of quantum states. To validate our proposal, we experimentally implement two purity detection methods in an optical system: shadow estimation with random measurements and collective measurements on pairs of state copies. The experiment shows that both the coherent information and the relative entropy of coherence of pure and mixed unknown quantum states can be bounded by purity functions. Our research offers an efficient means of verifying large-scale quantum information processing.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"53 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141329510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fault-tolerant connection of error-corrected qubits with noisy links 具有噪声链路的纠错量子比特的容错连接

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-06-10 DOI: 10.1038/s41534-024-00855-4

Joshua Ramette, Josiah Sinclair, Nikolas P. Breuckmann, Vladan Vuletić

引用次数: 0

Noisy qudit vs multiple qubits: conditions on gate efficiency for enhancing fidelity 噪声量子位与多量子位：提高保真度的栅极效率条件

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-06-10 DOI: 10.1038/s41534-024-00829-6

Denis Janković, Jean-Gabriel Hartmann, Mario Ruben, Paul-Antoine Hervieux

{"title":"Noisy qudit vs multiple qubits: conditions on gate efficiency for enhancing fidelity","authors":"Denis Janković, Jean-Gabriel Hartmann, Mario Ruben, Paul-Antoine Hervieux","doi":"10.1038/s41534-024-00829-6","DOIUrl":"https://doi.org/10.1038/s41534-024-00829-6","url":null,"abstract":"As qubit-based platforms face near-term technical challenges in terms of scalability, qudits, d-level bases of quantum information, are being implemented in multiple platforms as an alternative for Quantum Information Processing (QIP). We compare the infidelity scalings of single qudit and multiqubit systems within identical Hilbert space dimensions and noisy environments in the Lindblad formalism. We find them to be gate-independent to first-order and present an analytically-derived critical curve (({d}^{2}-1)/3{log }_{2}(d)) that benchmarks the operational time efficiency of qudits and qubits relative to their decoherence times. This comparison reveals conditions under which qudits offer competitive gate efficiencies compared to leading qubit platforms. Our findings, supported by numerical simulations testing the applicability and limits of the linear response formalism, highlight the relevance of qudits in near-term QIP. This provides a benchmark for evaluating qudit platforms, specifically those with lower dimensionality, in terms of their operational efficiency relative to the qubit state-of-the-art.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"85 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141304444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Group-theoretic error mitigation enabled by classical shadows and symmetries 通过经典阴影和对称性实现群论误差缓解

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-06-08 DOI: 10.1038/s41534-024-00854-5

Andrew Zhao, Akimasa Miyake

引用次数: 0

Quantum computing quantum Monte Carlo with hybrid tensor network for electronic structure calculations 利用混合张量网络进行量子计算的量子蒙特卡洛电子结构计算

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-06-06 DOI: 10.1038/s41534-024-00851-8

Shu Kanno, Hajime Nakamura, Takao Kobayashi, Shigeki Gocho, Miho Hatanaka, Naoki Yamamoto, Qi Gao

{"title":"Quantum computing quantum Monte Carlo with hybrid tensor network for electronic structure calculations","authors":"Shu Kanno, Hajime Nakamura, Takao Kobayashi, Shigeki Gocho, Miho Hatanaka, Naoki Yamamoto, Qi Gao","doi":"10.1038/s41534-024-00851-8","DOIUrl":"https://doi.org/10.1038/s41534-024-00851-8","url":null,"abstract":"Quantum computers have a potential for solving quantum chemistry problems with higher accuracy than classical computers. Quantum computing quantum Monte Carlo (QC-QMC) is a QMC with a trial state prepared in quantum circuit, which is employed to obtain the ground state with higher accuracy than QMC alone. We propose an algorithm combining QC-QMC with a hybrid tensor network to extend the applicability of QC-QMC beyond a single quantum device size. In a two-layer quantum-quantum tree tensor, our algorithm for the larger trial wave function can be executed than preparable wave function in a device. Our algorithm is evaluated on the Heisenberg chain model, graphite-based Hubbard model, hydrogen plane model, and MonoArylBiImidazole using full configuration interaction QMC. Our algorithm can achieve energy accuracy (specifically, variance) several orders of magnitude higher than QMC, and the hybrid tensor version of QMC gives the same energy accuracy as QC-QMC when the system is appropriately decomposed. Moreover, we develop a pseudo-Hadamard test technique that enables efficient overlap calculations between a trial wave function and an orthonormal basis state. In a real device experiment by using the technique, we obtained almost the same accuracy as the statevector simulator, indicating the noise robustness of our algorithm. These results suggests that the present approach will pave the way to electronic structure calculation for large systems with high accuracy on current quantum devices.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"4 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141264823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Microwave-multiplexed qubit controller using adiabatic superconductor logic 使用绝热超导体逻辑的微波多路复用量子比特控制器

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-06-03 DOI: 10.1038/s41534-024-00849-2

Naoki Takeuchi, Taiki Yamae, Taro Yamashita, Tsuyoshi Yamamoto, Nobuyuki Yoshikawa

{"title":"Microwave-multiplexed qubit controller using adiabatic superconductor logic","authors":"Naoki Takeuchi, Taiki Yamae, Taro Yamashita, Tsuyoshi Yamamoto, Nobuyuki Yoshikawa","doi":"10.1038/s41534-024-00849-2","DOIUrl":"https://doi.org/10.1038/s41534-024-00849-2","url":null,"abstract":"Cryogenic qubit controllers (QCs) are the key to build large-scale superconducting quantum processors. However, developing scalable QCs is challenging because the cooling power of a dilution refrigerator is too small (~10 μW at ~10 mK) to operate conventional logic families, such as complementary metal-oxide-semiconductor logic and superconducting single-flux-quantum logic, near qubits. Here we report on a scalable QC using an ultra-low-power superconductor logic family, namely adiabatic quantum-flux-parametron (AQFP) logic. The AQFP-based QC, referred to as the AQFP-multiplexed QC (AQFP-mux QC), produces multi-tone microwave signals for qubit control with an extremely small power dissipation of 81.8 pW per qubit. Furthermore, the AQFP-mux QC adopts microwave multiplexing to reduce the number of coaxial cables for operating the entire system. As a proof of concept, we demonstrate an AQFP-mux QC chip that produces microwave signals at two output ports through microwave multiplexing and demultiplexing. Experimental results show an output power of approximately −80 dBm and on/off ratio of ~40 dB at each output port. Basic mixing operation is also demonstrated by observing sideband signals.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"46 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141236008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantum computation of frequency-domain molecular response properties using a three-qubit iToffoli gate 利用三量子位 iToffoli 门实现频域分子响应特性的量子计算

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-05-31 DOI: 10.1038/s41534-024-00850-9

Shi-Ning Sun, Brian Marinelli, Jin Ming Koh, Yosep Kim, Long B. Nguyen, Larry Chen, John Mark Kreikebaum, David I. Santiago, Irfan Siddiqi, Austin J. Minnich

{"title":"Quantum computation of frequency-domain molecular response properties using a three-qubit iToffoli gate","authors":"Shi-Ning Sun, Brian Marinelli, Jin Ming Koh, Yosep Kim, Long B. Nguyen, Larry Chen, John Mark Kreikebaum, David I. Santiago, Irfan Siddiqi, Austin J. Minnich","doi":"10.1038/s41534-024-00850-9","DOIUrl":"https://doi.org/10.1038/s41534-024-00850-9","url":null,"abstract":"The quantum computation of molecular response properties on near-term quantum hardware is a topic of substantial interest. Computing these properties directly in the frequency domain is desirable, but the circuits require large depth if the typical hardware gate set consisting of single- and two-qubit gates is used. While high-fidelity multipartite gates have been reported recently, their integration into quantum simulation and the demonstration of improved accuracy of the observable properties remains to be shown. Here, we report the application of a high-fidelity multipartite gate, the iToffoli gate, to the computation of frequency-domain response properties of diatomic molecules. The iToffoli gate enables a ~50% reduction in circuit depth and ~40% reduction in circuit execution time compared to the traditional gate set. We show that the molecular properties obtained with the iToffoli gate exhibit comparable or better agreement with theory than those obtained with the native CZ gates. Our work is among the first demonstrations of the practical usage of a native multi-qubit gate in quantum simulation, with diverse potential applications to near-term quantum computation.","PeriodicalId":19212,"journal":{"name":"npj Quantum Information","volume":"50 1","pages":""},"PeriodicalIF":7.6,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141185239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Coupling conduction-band valleys in SiGe heterostructures via shear strain and Ge concentration oscillations 通过剪切应变和 Ge 浓度振荡耦合硅-锗异质结构中的导带谷

IF 7.6 1区物理与天体物理

npj Quantum Information Pub Date : 2024-05-31 DOI: 10.1038/s41534-024-00853-6

Benjamin D. Woods, Hudaiba Soomro, E. S. Joseph, Collin C. D. Frink, Robert Joynt, M. A. Eriksson, Mark Friesen

引用次数: 0