Quantum Science and Technology最新文献_第5页

Beyond quantum annealing: optimal control solutions to maxcut problems 超越量子退火：最大切割问题的最优控制解决方案

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-17 DOI: 10.1088/2058-9565/ad60f2

Giovanni Pecci, Ruiyi Wang, Pietro Torta, Glen Bigan Mbeng and Giuseppe Santoro

{"title":"Beyond quantum annealing: optimal control solutions to maxcut problems","authors":"Giovanni Pecci, Ruiyi Wang, Pietro Torta, Glen Bigan Mbeng and Giuseppe Santoro","doi":"10.1088/2058-9565/ad60f2","DOIUrl":"https://doi.org/10.1088/2058-9565/ad60f2","url":null,"abstract":"Quantum Annealing (QA) relies on mixing two Hamiltonian terms, a simple driver and a complex problem Hamiltonian, in a linear combination. The time-dependent schedule for this mixing is often taken to be linear in time: improving on this linear choice is known to be essential and has proven to be difficult. Here, we present different techniques for improving on the linear-schedule QA along two directions, conceptually distinct but leading to similar outcomes: 1) the first approach consists of constructing a Trotter-digitized QA (dQA) with schedules parameterized in terms of Fourier modes or Chebyshev polynomials, inspired by the Chopped Random Basis algorithm for optimal control in continuous time; 2) the second approach is technically a Quantum Approximate Optimization Algorithm (QAOA), whose solutions are found iteratively using linear interpolation or expansion in Fourier modes. Both approaches emphasize finding smooth optimal schedule parameters, ultimately leading to hybrid quantum–classical variational algorithms of the alternating Hamiltonian Ansatz type. We apply these techniques to MaxCut problems on weighted 3-regular graphs with N = 14 sites, focusing on hard instances that exhibit a small spectral gap, for which a standard linear-schedule QA performs poorly. We characterize the physics behind the optimal protocols for both the dQA and QAOA approaches, discovering shortcuts to adiabaticity-like dynamics. Furthermore, we study the transferability of such smooth solutions among hard instances of MaxCut at different circuit depths. Finally, we show that the smoothness pattern of these protocols obtained in a digital setting enables us to adapt them to continuous-time evolution, contrarily to generic non-smooth solutions. This procedure results in an optimized QA schedule that is implementable on analog devices.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141726177","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

Lift-connected surface codes 电梯连接表面代码

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-16 DOI: 10.1088/2058-9565/ad5eb6

Josias Old, Manuel Rispler and Markus Müller

{"title":"Lift-connected surface codes","authors":"Josias Old, Manuel Rispler and Markus Müller","doi":"10.1088/2058-9565/ad5eb6","DOIUrl":"https://doi.org/10.1088/2058-9565/ad5eb6","url":null,"abstract":"We use the recently introduced lifted product to construct a family of quantum low density parity check codes (QLDPC codes). The codes we obtain can be viewed as stacks of surface codes that are interconnected, leading to the name lift-connected surface (LCS) codes. LCS codes offer a wide range of parameters—a particularly striking feature is that they show interesting properties that are favorable compared to the standard surface code. For example, already at moderate numbers of physical qubits in the order of tens, LCS codes of equal size have lower logical error rate or similarly, require fewer qubits for a fixed target logical error rate. We present and analyze the construction and provide numerical simulation results for the logical error rate under code capacity and phenomenological noise. These results show that LCS codes attain thresholds that are comparable to corresponding (non-connected) copies of surface codes, while the logical error rate can be orders of magnitude lower, even for representatives with the same parameters. This provides a code family showing the potential of modern product constructions at already small qubit numbers. Their amenability to 3D-local connectivity renders them particularly relevant for near-term implementations.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141631285","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

Towards interpretable quantum machine learning via single-photon quantum walks 通过单光子量子行走实现可解释的量子机器学习

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-14 DOI: 10.1088/2058-9565/ad5907

Fulvio Flamini, Marius Krumm, Lukas J Fiderer, Thomas Müller and Hans J Briegel

引用次数: 0

A chip-integrated homodyne detection system with enhanced bandwidth performance for quantum applications 为量子应用提供带宽性能更强的芯片集成同调探测系统

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-14 DOI: 10.1088/2058-9565/ad5d10

Si Qi Ng, Gong Zhang, Charles Lim and Chao Wang

{"title":"A chip-integrated homodyne detection system with enhanced bandwidth performance for quantum applications","authors":"Si Qi Ng, Gong Zhang, Charles Lim and Chao Wang","doi":"10.1088/2058-9565/ad5d10","DOIUrl":"https://doi.org/10.1088/2058-9565/ad5d10","url":null,"abstract":"The rapid development of quantum technology has driven the need for high-performance quantum signal processing modules. Balanced homodyne detector (BHD) is one of the most promising options for practical quantum state measurement, providing substantial advantages of cost-effectiveness, no cooling requirement, and system compactness. However, due to the stringent requirements in BHD design, it typically suffers from a relatively small operating bandwidth which limits the overall speed of a quantum system. In this study, we propose comprehensive modelling for the BHD in quantum applications and enhance the performance of BHDs based on our modelling. Specifically, we utilise a photonic chip approach and optimise the electronic design to create the integrated BHD, which significantly boosts the 3 dB bandwidth to 4.75 GHz and achieves a shot-noise-limited bandwidth of 23 GHz. We demonstrate the capability of this setup to generate quantum random numbers at a rate of 240 Gbit s−1, highlighting its potential for ultra-high-speed quantum communication and quantum cryptography applications.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141618283","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

Quanto: optimizing quantum circuits with automatic generation of circuit identities Quanto：通过自动生成电路标识优化量子电路

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-11 DOI: 10.1088/2058-9565/ad5b16

Jessica Pointing, Oded Padon, Zhihao Jia, Henry Ma, Auguste Hirth, Jens Palsberg and Alex Aiken

{"title":"Quanto: optimizing quantum circuits with automatic generation of circuit identities","authors":"Jessica Pointing, Oded Padon, Zhihao Jia, Henry Ma, Auguste Hirth, Jens Palsberg and Alex Aiken","doi":"10.1088/2058-9565/ad5b16","DOIUrl":"https://doi.org/10.1088/2058-9565/ad5b16","url":null,"abstract":"Existing quantum compilers focus on mapping a logical quantum circuit to a quantum device and its native quantum gates. Only simple circuit identities are used to optimize the quantum circuit during the compilation process. This approach misses more complex circuit identities, which could be used to optimize the quantum circuit further. We propose Quanto, the first quantum optimizer that automatically generates circuit identities. Quanto takes as input a gate set and generates provably correct circuit identities for the gate set. Quanto’s automatic generation of circuit identities includes single-qubit and two-qubit gates, which leads to a new database of circuit identities, some of which are novel to the best of our knowledge. In addition to the generation of new circuit identities, Quanto’s optimizer applies such circuit identities to quantum circuits and finds optimized quantum circuits that have not been discovered by other quantum compilers, including IBM Qiskit and Cambridge Quantum Computing Tket. Quanto’s database of circuit identities could be applied to improve existing quantum compilers and Quanto can be used to generate identity databases for new gate sets.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141597504","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

Experimental Realization of Active Nonlinear Feedback Control from Hot Rubidium Vapor 热铷蒸汽主动非线性反馈控制的实验实现

IF 5.6 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-10 DOI: 10.1088/2058-9565/ad617f

Xiaozhou Pan, Tianxiang Wei, Kai Zhang, Jietai Jing

{"title":"Experimental Realization of Active Nonlinear Feedback Control from Hot Rubidium Vapor","authors":"Xiaozhou Pan, Tianxiang Wei, Kai Zhang, Jietai Jing","doi":"10.1088/2058-9565/ad617f","DOIUrl":"https://doi.org/10.1088/2058-9565/ad617f","url":null,"abstract":"\u0000 Feedback control plays a crucial role in preparation and manipulation of quantum states, to evolve the quantum system towards a desired result. Here we report a novel feedback control system utilizing two four-wave mixing (FWM) processes, in which the first FWM process functions as an amplifier while the second FWM process serves as an active nonlinear controller. We experimentally investigate the classical properties of the output states, and demonstrate the manipulation of quantum states through the active nonlinear controller. Remarkably, we observe that the quantum correlation of the quantum states can be efficiently controlled and enhanced, even when the amplifier operates at a significantly low level of pump power. Furthermore, we identify an optimal intensity gain for the active nonlinear controller, which maximizes the quantum correlation of the system. These findings present a new strategy employing an active controller to enhance quantum correlation, which holds the potential to improve the communication fidelity of quantum information processing and enhance the measurement precision of quantum metrology in future applications.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141661124","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

Asymptotic teleportation scheme bridging between standard and port-based teleportation 在标准传送和基于端口的传送之间架起桥梁的渐近传送方案

IF 5.6 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-10 DOI: 10.1088/2058-9565/ad617e

Ha Eum Kim, Kabgyun Jeong

{"title":"Asymptotic teleportation scheme bridging between standard and port-based teleportation","authors":"Ha Eum Kim, Kabgyun Jeong","doi":"10.1088/2058-9565/ad617e","DOIUrl":"https://doi.org/10.1088/2058-9565/ad617e","url":null,"abstract":"\u0000 Various modified quantum teleportation schemes are proposed to overcome experimental constraints or to meet specific application requirements for quantum communication. Hence, most schemes are developed and studied with unique methodologies, each with its own inherent challenges. Our research focuses on interconnecting these schemes, which appear to be unrelated to each other, based on the idea that the unique advantages of one scheme can compensate for the limitations of another. In this paper, we introduce an asymptotic teleportation scheme that requires the receiver to complete a classical selection task before performing a quantum correction. This scheme bridges standard teleportation with port-based teleportation through the transformation of joint measurements. Specifically, we categorize and analytically investigate protocols within this scheme for qubit systems. Given that the linear optics teleportation protocol without ancilla qubits is contained in the two non-trivial groups, we provide a novel perspective on its expansion. Furthermore, we discuss the potential application of a protocol from one of these groups as a universal programmable processor and extend these protocols to higher-dimensional systems while maintaining the same properties and potential, providing the analytic form of the joint measurement and its performance. These results thereby propose new avenues for developing a quantum network in higher-dimensional systems.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141661731","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

Interplay among entanglement, measurement incompatibility, and nonlocality 纠缠、测量不兼容性和非实时性之间的相互作用

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-09 DOI: 10.1088/2058-9565/ad5aba

Yuwei Zhu, Xingjian Zhang and Xiongfeng Ma

引用次数: 0

Non-unitary Trotter circuits for imaginary time evolution 虚时演化的非单元特罗特电路

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-08 DOI: 10.1088/2058-9565/ad53fb

Chiara Leadbeater, Nathan Fitzpatrick, David Muñoz Ramo and Alex J W Thom

{"title":"Non-unitary Trotter circuits for imaginary time evolution","authors":"Chiara Leadbeater, Nathan Fitzpatrick, David Muñoz Ramo and Alex J W Thom","doi":"10.1088/2058-9565/ad53fb","DOIUrl":"https://doi.org/10.1088/2058-9565/ad53fb","url":null,"abstract":"We propose an imaginary time equivalent of the well-established Pauli gadget primitive for Trotter-decomposed real time evolution, using mid-circuit measurements on a single ancilla qubit. Imaginary time evolution (ITE) is widely used for obtaining the ground state (GS) of a system on classical hardware, computing thermal averages, and as a component of quantum algorithms that perform non-unitary evolution. Near-term implementations on quantum hardware rely on heuristics, compromising their accuracy. As a result, there is growing interest in the development of more natively quantum algorithms. Since it is not possible to implement a non-unitary gate deterministically, we resort to the implementation of probabilistic ITE (PITE) algorithms, which rely on a unitary quantum circuit to simulate a block encoding of the ITE operator—that is, they rely on successful ancillary measurements to evolve the system non-unitarily. Compared with previous PITE proposals, the suggested block encoding in this paper results in shorter circuits and is simpler to implement, requiring only a slight modification of the Pauli gadget primitive. This scheme was tested on the transverse Ising model and the fermionic Hubbard model and is demonstrated to converge to the GS of the system.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141561367","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

Quantum computer-enabled receivers for optical communication 用于光通信的量子计算机接收器

IF 6.7 2区物理与天体物理

Quantum Science and Technology Pub Date : 2024-07-07 DOI: 10.1088/2058-9565/ad5abb

John Crossman, Spencer Dimitroff, Lukasz Cincio and Mohan Sarovar

{"title":"Quantum computer-enabled receivers for optical communication","authors":"John Crossman, Spencer Dimitroff, Lukasz Cincio and Mohan Sarovar","doi":"10.1088/2058-9565/ad5abb","DOIUrl":"https://doi.org/10.1088/2058-9565/ad5abb","url":null,"abstract":"Optical communication is the standard for high-bandwidth information transfer in today’s digital age. The increasing demand for bandwidth has led to the maturation of coherent transceivers that use phase- and amplitude-modulated optical signals to encode more bits of information per transmitted pulse. Such encoding schemes achieve higher information density, but also require more complicated receivers to discriminate the signaling states. In fact, achieving the ultimate limit of optical communication capacity, especially in the low light regime, requires coherent joint detection of multiple pulses. Despite their superiority, such joint detection receivers are not in widespread use because of the difficulty of constructing them in the optical domain. In this work we describe how optomechanical transduction of phase information from coherent optical pulses to superconducting qubit states followed by the execution of trained short-depth variational quantum circuits can perform joint detection of communication codewords with error probabilities that surpass all classical, individual pulse detection receivers. Importantly, we utilize a model of optomechanical transduction that captures non-idealities such as thermal noise and loss in order to understand the transduction performance necessary to achieve a quantum advantage with such a scheme. We also execute the trained variational circuits on an IBM-Q device with the modeled transduced states as input to demonstrate that a quantum advantage is possible even with current levels of quantum computing hardware noise.","PeriodicalId":20821,"journal":{"name":"Quantum Science and Technology","volume":null,"pages":null},"PeriodicalIF":6.7,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141556760","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