Quantum Science and Technology最新文献_第4页

A square-root speedup for finding the smallest eigenvalue 寻找最小特征值的平方根速度提升

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-08-11 DOI: 10.1088/2058-9565/ad6a36

Alex Kerzner, Vlad Gheorghiu, Michele Mosca, Thomas Guilbaud, Federico Carminati, Fabio Fracas and Luca Dellantonio

引用次数: 0

Bang-bang optimal control in coherent spin dynamics of radical pairs in quantum biology 量子生物学中自由基对相干自旋动力学的 Bang-bang 优化控制

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-08-07 DOI: 10.1088/2058-9565/ad68a1

Ugur G Abdulla, Jose Rodrigues, Pablo Jimenez, Chenming Zhen and Carlos Martino

引用次数: 0

Ratchet loading and multi-ensemble operation in an optical lattice clock 光晶格时钟中的棘轮加载和多组合运行

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-08-07 DOI: 10.1088/2058-9565/ad6286

Youssef S Hassan, Takumi Kobayashi, Tobias Bothwell, Jacob L Seigel, Benjamin D Hunt, Kyle Beloy, Kurt Gibble, Tanner Grogan and Andrew D Ludlow

{"title":"Ratchet loading and multi-ensemble operation in an optical lattice clock","authors":"Youssef S Hassan, Takumi Kobayashi, Tobias Bothwell, Jacob L Seigel, Benjamin D Hunt, Kyle Beloy, Kurt Gibble, Tanner Grogan and Andrew D Ludlow","doi":"10.1088/2058-9565/ad6286","DOIUrl":"https://doi.org/10.1088/2058-9565/ad6286","url":null,"abstract":"We demonstrate programmable control over the spatial distribution of ultra-cold atoms confined in an optical lattice. The control is facilitated through a combination of spatial manipulation of the magneto-optical trap and atomic population shelving to a metastable state. We first employ the technique to load an extended (5 mm) atomic sample with uniform density in an optical lattice clock (OLC), reducing atomic interactions and realizing remarkable frequency homogeneity across the atomic cloud. We also prepare multiple spatially separated atomic ensembles, and realize multi-ensemble clock operation within the standard one-dimensional (1D) OLC architecture. Leveraging this technique, we prepare two oppositely spin-polarized ensembles that are independently addressable, offering a platform for implementing spectroscopic protocols for enhanced tracking of local oscillator phase. Finally, we demonstrate a relative fractional frequency instability at one second of between two ensembles, useful for characterization of intra-lattice differential systematics.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141904524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Optimal and robust quantum state tomography of star-topology register 星型拓扑寄存器的最优鲁棒量子态层析

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-08-07 DOI: 10.1088/2058-9565/ad692c

Ran Liu, Yanjun Hou, Ze Wu, Hui Zhou, Jiahui Chen, Zhaokai Li and Xinhua Peng

{"title":"Optimal and robust quantum state tomography of star-topology register","authors":"Ran Liu, Yanjun Hou, Ze Wu, Hui Zhou, Jiahui Chen, Zhaokai Li and Xinhua Peng","doi":"10.1088/2058-9565/ad692c","DOIUrl":"https://doi.org/10.1088/2058-9565/ad692c","url":null,"abstract":"While quantum state tomography plays a vital role in the verification and benchmarking of quantum systems, it is an intractable task if the controllability of the quantum registers is constrained. In this paper, we propose a novel scheme for optimal and robust quantum state tomography for systems with constrained controllability. Based on the specific symmetry, we decompose the Hilbert space to alleviate the complexity of tomography and design a compact strategy with the minimum number of measurements. To switch between these measurement settings, we adopted parameterized quantum circuits consisting of local operations and free evolution, which are easy to implement in most practical systems. Then the parameters of these circuits were optimized to improve the robustness against errors of measurements. We demonstrated the experimental feasibility of our method on a 4-spin star-topology register and numerically studied its ability to characterize large-scale systems on a 10-spin star-topology register, respectively. Our results can help future investigations of quantum systems with constrained ability of quantum control and measurement.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141904525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Distributing circuits over heterogeneous, modular quantum computing network architectures 在异构模块化量子计算网络架构上分配电路

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-08-05 DOI: 10.1088/2058-9565/ad6734

Pablo Andres-Martinez, Tim Forrer, Daniel Mills, Jun-Yi Wu, Luciana Henaut, Kentaro Yamamoto, Mio Murao and Ross Duncan

{"title":"Distributing circuits over heterogeneous, modular quantum computing network architectures","authors":"Pablo Andres-Martinez, Tim Forrer, Daniel Mills, Jun-Yi Wu, Luciana Henaut, Kentaro Yamamoto, Mio Murao and Ross Duncan","doi":"10.1088/2058-9565/ad6734","DOIUrl":"https://doi.org/10.1088/2058-9565/ad6734","url":null,"abstract":"We consider a heterogeneous network of quantum computing modules, sparsely connected via Bell states. Operations across these connections constitute a computational bottleneck and they are likely to add more noise to the computation than operations performed within a module. We introduce several techniques for transforming a given quantum circuit into one implementable on such a network, minimising the number of Bell states required to do so. We extend previous works on circuit distribution to the case of heterogeneous networks. On the one hand, we extend the hypergraph approach of Andres-Martinez and Heunen (2019 Phys. Rev. A 100 032308) to arbitrary network topologies, and we propose the use of Steiner trees to detect and reuse common connections, further reducing the cost of entanglement sharing within the network. On the other hand, we extend the embedding techniques of Wu et al (2023 Quantum7 1196) to networks with more than two modules. We show that, with careful manipulation of trade-offs, these two new approaches can be combined into a single automated framework. Our proposal is implemented and benchmarked; the results confirm that our contributions make noticeable improvements upon the aforementioned works and complement their weaknesses.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141895498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Conditional quantum thermometry—enhancing precision by measuring less 条件量子测温--通过减少测量提高精度

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-08-01 DOI: 10.1088/2058-9565/ad6736

Akira Sone, Diogo O Soares-Pinto and Sebastian Deffner

引用次数: 0

Emergence of noise-induced barren plateaus in arbitrary layered noise models 在任意分层噪声模型中出现噪声诱发的贫瘠高原

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-08-01 DOI: 10.1088/2058-9565/ad6285

M Schumann, F K Wilhelm and A Ciani

{"title":"Emergence of noise-induced barren plateaus in arbitrary layered noise models","authors":"M Schumann, F K Wilhelm and A Ciani","doi":"10.1088/2058-9565/ad6285","DOIUrl":"https://doi.org/10.1088/2058-9565/ad6285","url":null,"abstract":"In variational quantum algorithms the parameters of a parameterized quantum circuit are optimized in order to minimize a cost function that encodes the solution of the problem. The barren plateau phenomenon manifests as an exponentially vanishing dependence of the cost function with respect to the variational parameters, and thus hampers the optimization process. We discuss how, and in which sense, the phenomenon of noise-induced barren plateaus emerges in parameterized quantum circuits with a layered noise model. Previous results have shown the existence of noise-induced barren plateaus in the presence of local Pauli noise (Wang et al 2021 Nat. Commun.12 6961). We extend these results analytically to arbitrary completely-positive trace preserving maps in two cases: (1) when a parameter-shift rule holds, (2) when the parameterized quantum circuit at each layer forms a unitary 2-design. The second example shows how highly expressive unitaries give rise not only to standard barren plateaus (McClean et al 2018 Nat. Commun.9 4812), but also to noise-induced ones. In the second part of the paper, we study numerically the emergence of noise-induced barren plateaus in QAOA circuits focusing on the case of MaxCut problems on d-regular graphs and amplitude damping noise.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Nonequilibrium fluctuations of a quantum heat engine 量子热机的非平衡波动

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-31 DOI: 10.1088/2058-9565/ad6287

Tobias Denzler, Jonas F G Santos, Eric Lutz and Roberto M Serra

引用次数: 0

Integer programming using a single atom 使用单原子的整数编程

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-31 DOI: 10.1088/2058-9565/ad6735

Kapil Goswami, Peter Schmelcher and Rick Mukherjee

{"title":"Integer programming using a single atom","authors":"Kapil Goswami, Peter Schmelcher and Rick Mukherjee","doi":"10.1088/2058-9565/ad6735","DOIUrl":"https://doi.org/10.1088/2058-9565/ad6735","url":null,"abstract":"Integer programming (IP), as the name suggests is an integer-variable-based approach commonly used to formulate real-world optimization problems with constraints. Currently, quantum algorithms reformulate the IP into an unconstrained form through the use of binary variables, which is an indirect and resource-consuming way of solving it. We develop an algorithm that maps and solves an IP problem in its original form to any quantum system possessing a large number of accessible internal degrees of freedom that are controlled with sufficient accuracy. This work leverages the principle of superposition to solve the optimization problem. Using a single Rydberg atom as an example, we associate the integer values to electronic states belonging to different manifolds and implement a selective superposition of different states to solve the full IP problem. The optimal solution is found within a few microseconds for prototypical IP problems with up to eight variables and four constraints. This also includes non-linear IP problems, which are usually harder to solve with classical algorithms when compared to their linear counterparts. Our algorithm for solving IP is benchmarked by a well-known classical algorithm (branch and bound) in terms of the number of steps needed for convergence to the solution. This approach carries the potential to improve the solutions obtained for larger-size problems using hybrid quantum–classical algorithms.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141862267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Counterfactuality, back-action, and information gain in multi-path interferometers 多路径干涉仪中的反事实性、反向作用和信息增益

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-23 DOI: 10.1088/2058-9565/ad63c7

Jonte R Hance, Tomonori Matsushita and Holger F Hofmann

{"title":"Counterfactuality, back-action, and information gain in multi-path interferometers","authors":"Jonte R Hance, Tomonori Matsushita and Holger F Hofmann","doi":"10.1088/2058-9565/ad63c7","DOIUrl":"https://doi.org/10.1088/2058-9565/ad63c7","url":null,"abstract":"The presence of an absorber in one of the paths of an interferometer changes the output statistics of that interferometer in a fundamental manner. Since the individual quantum particles detected at any of the outputs of the interferometer have not been absorbed, any non-trivial effect of the absorber on the distribution of these particles over these paths is a counterfactual effect. Here, we quantify counterfactual effects by evaluating the information about the presence or absence of the absorber obtained from the output statistics, distinguishing between classical and quantum counterfactual effects. We identify the counterfactual gain which quantifies the advantage of quantum counterfactual protocols over classical counterfactual protocols, and show that this counterfactual gain can be separated into two terms: a semi-classical term related to the amplitude blocked by the absorber, and a Kirkwood-Dirac quasiprobability assigning a joint probability to the blocked path and the output port. A negative Kirkwood-Dirac term between a path and an output port indicates that inserting the absorber into that path will have a focussing effect, increasing the probability of particles arriving at that output port, resulting in a significant enhancement of the counterfactual gain. We show that the magnitude of quantum counterfactual effects cannot be explained by a simple removal of the absorbed particles, but originates instead from a well-defined back-action effect caused by the presence of the absorber in one path, on particles in other paths.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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