EPJ Quantum Technology最新文献_第2页

Experimental demonstration of quantum encryption in phase space with displacement operator in coherent optical communications 相干光通信中带有位移算子的相空间量子加密实验演示

IF 5.8 2区物理与天体物理

EPJ Quantum Technology Pub Date : 2024-07-31 DOI: 10.1140/epjqt/s40507-024-00260-y

Mostafa Khalil, Adrian Chan, David V. Plant, Lawrence R. Chen, Randy Kuang

{"title":"Experimental demonstration of quantum encryption in phase space with displacement operator in coherent optical communications","authors":"Mostafa Khalil, Adrian Chan, David V. Plant, Lawrence R. Chen, Randy Kuang","doi":"10.1140/epjqt/s40507-024-00260-y","DOIUrl":"10.1140/epjqt/s40507-024-00260-y","url":null,"abstract":"<div><p>We provide experimental validation of quantum encryption in phase space using displacement operators in coherent states (DOCS) in a conventional coherent optical communication system. The proposed encryption technique is based on displacing the information symbols in the phase space using random phases and amplitudes to achieve encryption randomly and provide security at the physical layer. We also introduce a dual polarization encryption approach where we use two different and random DOCS to encrypt the X and Y polarizations separately. The experimental results show that only authorized users can decrypt the signal correctly, and any mismatch in the displacement operator coefficients, amplitudes, or phases will lead to a bit error ratio (BER) of approximately 50%. We also compare the performance of the system with and without encryption over 80 km of standard-single mode fiber (SSMF) transmission to assess the added penalty of such encryption. The achieved net bit rates are 224, 448, and 560 Gb/s for QPSK, 16QAM, and 32QAM modulation formats, respectively. The experimental results showcase the efficacy of the DOCS encryption technique in resisting various decryption attempts, demonstrating its effectiveness in ensuring the security and confidentiality of transmitted data in a real-world transmission scenario.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":null,"pages":null},"PeriodicalIF":5.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://epjquantumtechnology.springeropen.com/counter/pdf/10.1140/epjqt/s40507-024-00260-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optical payload design for downlink quantum key distribution and keyless communication using CubeSats 利用立方体卫星进行下行链路量子密钥分发和无密钥通信的光学有效载荷设计

IF 5.8 2区物理与天体物理

EPJ Quantum Technology Pub Date : 2024-07-30 DOI: 10.1140/epjqt/s40507-024-00254-w

Pedro Neto Mendes, Gonçalo Lobato Teixeira, David Pinho, Rui Rocha, Paulo André, Manfred Niehus, Ricardo Faleiro, Davide Rusca, Emmanuel Zambrini Cruzeiro

{"title":"Optical payload design for downlink quantum key distribution and keyless communication using CubeSats","authors":"Pedro Neto Mendes, Gonçalo Lobato Teixeira, David Pinho, Rui Rocha, Paulo André, Manfred Niehus, Ricardo Faleiro, Davide Rusca, Emmanuel Zambrini Cruzeiro","doi":"10.1140/epjqt/s40507-024-00254-w","DOIUrl":"10.1140/epjqt/s40507-024-00254-w","url":null,"abstract":"<div><p>Quantum key distribution is costly and, at the moment, offers low performance in space applications. Other more recent protocols could offer a potential practical solution to this problem. In this work, a preliminary optical payload design using commercial off-the-shelf elements for a quantum communication downlink in a 3U CubeSat is proposed. It is shown that this quantum state emitter allows the establishment of two types of quantum communication between the satellite and the ground station: quantum key distribution and quantum keyless private communication. Numerical simulations are provided that show the feasibility of the scheme for both protocols as well as their performance. For the simplified BB84, a maximum secret key rate of about 80 kHz and minimum QBER of slightly more than 0.07% is found, at the zenith, while for quantum private keyless communication, a 700 MHz private rate is achieved. This design serves as a platform for the implementation of novel quantum communication protocols that can improve the performance of quantum communications in space.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":null,"pages":null},"PeriodicalIF":5.8,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://epjquantumtechnology.springeropen.com/counter/pdf/10.1140/epjqt/s40507-024-00254-w","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantum multi-state Swap Test: an algorithm for estimating overlaps of arbitrary number quantum states 量子多态交换测试：一种估算任意数量量子态重叠的算法

IF 5.8 2区物理与天体物理

EPJ Quantum Technology Pub Date : 2024-07-25 DOI: 10.1140/epjqt/s40507-024-00259-5

Wen Liu, Yang-Zhi Li, Han-Wen Yin, Zhi-Rao Wang, Jiang Wu

{"title":"Quantum multi-state Swap Test: an algorithm for estimating overlaps of arbitrary number quantum states","authors":"Wen Liu, Yang-Zhi Li, Han-Wen Yin, Zhi-Rao Wang, Jiang Wu","doi":"10.1140/epjqt/s40507-024-00259-5","DOIUrl":"10.1140/epjqt/s40507-024-00259-5","url":null,"abstract":"<div><p>Estimating the overlap between two states is an important task with several applications in quantum information. However, the typical swap test circuit can only measure a sole pair of quantum states at a time. In this study, a recursive quantum circuit is designed to measure overlaps of <i>n</i> quantum states <span>(left | {phi _{1} } right rangle ,left | {phi _{2} } right rangle ,ldotsleft | {phi _{n} }right rangle )</span> concurrently with <span>(O(k2^{k}))</span> controlled-swap(CSWAP) gates and <span>(O(k))</span> ancillary qubits, where <span>(k=left lceil {log n} right rceil )</span>. All pairwise overlaps among input quantum states <span>(|langle phi _{i}|phi _{j}rangle |^{2})</span> can be obtained in this circuit. Compared with existing scheme for measuring the overlap of multiple quantum states, the circuit provides higher precision and less consumption of ancillary qubits. In addition, some simulation experiments are performed on IBM quantum cloud platform to verify the superiority of this algorithm.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":null,"pages":null},"PeriodicalIF":5.8,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://epjquantumtechnology.springeropen.com/counter/pdf/10.1140/epjqt/s40507-024-00259-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141771216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On validity of quantum partial adiabatic search 论量子部分绝热搜索的有效性

IF 5.8 2区物理与天体物理

EPJ Quantum Technology Pub Date : 2024-07-25 DOI: 10.1140/epjqt/s40507-024-00258-6

Jie Sun, Dunbo Cai, Songfeng Lu, Ling Qian, Runqing Zhang

引用次数: 0

Synergy between noisy quantum computers and scalable classical deep learning for quantum error mitigation 噪声量子计算机与可扩展经典深度学习之间的协同作用，实现量子错误缓解

IF 5.8 2区物理与天体物理

EPJ Quantum Technology Pub Date : 2024-07-15 DOI: 10.1140/epjqt/s40507-024-00256-8

Simone Cantori, Andrea Mari, David Vitali, Sebastiano Pilati

{"title":"Synergy between noisy quantum computers and scalable classical deep learning for quantum error mitigation","authors":"Simone Cantori, Andrea Mari, David Vitali, Sebastiano Pilati","doi":"10.1140/epjqt/s40507-024-00256-8","DOIUrl":"10.1140/epjqt/s40507-024-00256-8","url":null,"abstract":"<div><p>We investigate the potential of combining the computational power of noisy quantum computers and of classical scalable convolutional neural networks (CNNs). The goal is to accurately predict exact expectation values of parameterized quantum circuits representing the Trotter-decomposed dynamics of quantum Ising models. By incorporating (simulated) noisy expectation values alongside circuit structure information, our CNNs effectively capture the underlying relationships between circuit architecture and output behaviour, enabling, via transfer learning, also predictions for circuits with more qubits than those included in the training set. Notably, thanks to the quantum information, our CNNs succeed even when supervised learning based only on classical descriptors fails. Furthermore, they outperform a popular error mitigation scheme, namely, zero-noise extrapolation, demonstrating that the synergy between quantum and classical computational tools leads to higher accuracy compared with quantum-only or classical-only approaches. By tuning the noise strength, we explore the crossover from a computationally powerful classical CNN assisted by quantum noisy data, towards rather precise quantum computations, further error-mitigated via classical deep learning.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":null,"pages":null},"PeriodicalIF":5.8,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://epjquantumtechnology.springeropen.com/counter/pdf/10.1140/epjqt/s40507-024-00256-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141618157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A meta-trained generator for quantum architecture search 用于量子架构搜索的元训练生成器

IF 5.8 2区物理与天体物理

EPJ Quantum Technology Pub Date : 2024-07-09 DOI: 10.1140/epjqt/s40507-024-00255-9

Zhimin He, Chuangtao Chen, Zhengjiang Li, Haozhen Situ, Fei Zhang, Shenggen Zheng, Lvzhou Li

{"title":"A meta-trained generator for quantum architecture search","authors":"Zhimin He, Chuangtao Chen, Zhengjiang Li, Haozhen Situ, Fei Zhang, Shenggen Zheng, Lvzhou Li","doi":"10.1140/epjqt/s40507-024-00255-9","DOIUrl":"10.1140/epjqt/s40507-024-00255-9","url":null,"abstract":"<div><p>Variational Quantum Algorithms (VQAs) have made great success in the Noisy Intermediate-Scale Quantum (NISQ) era due to their relative resilience to noise and high flexibility relative to quantum resources. Quantum Architecture Search (QAS) aims to enhance the performance of VQAs by refining the structure of the adopted Parameterized Quantum Circuit (PQC). QAS is garnering increased attention owing to its automation, reduced reliance on expert experience, and its ability to achieve better performance while requiring fewer quantum gates than manually designed circuits. However, existing QAS algorithms optimize the structure from scratch for each VQA without using any prior experience, rendering the process inefficient and time-consuming. Moreover, determining the number of quantum gates, a crucial hyper-parameter in these algorithms is a challenging and time-consuming task. To mitigate these challenges, we accelerate the QAS algorithm via a meta-trained generator. The proposed algorithm directly generates high-performance circuits for a new VQA by utilizing a meta-trained Variational AutoEncoder (VAE). The number of quantum gates required in the designed circuit is automatically determined based on meta-knowledge learned from a variety of training tasks. Furthermore, we have developed a meta-predictor to filter out circuits with suboptimal performance, thereby accelerating the algorithm. Simulation results on variational quantum compiling and Quantum Approximation Optimization Algorithm (QAOA) demonstrate the superior performance of our method over a state-of-the-art algorithm, namely Differentiable Quantum Architecture Search (DQAS).</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":null,"pages":null},"PeriodicalIF":5.8,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://epjquantumtechnology.springeropen.com/counter/pdf/10.1140/epjqt/s40507-024-00255-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141561131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Efficient realization of quantum algorithms with qudits 用量子比特高效实现量子算法

IF 5.8 2区物理与天体物理

EPJ Quantum Technology Pub Date : 2024-06-26 DOI: 10.1140/epjqt/s40507-024-00250-0

Anastasiia S. Nikolaeva, Evgeniy O. Kiktenko, Aleksey K. Fedorov

{"title":"Efficient realization of quantum algorithms with qudits","authors":"Anastasiia S. Nikolaeva, Evgeniy O. Kiktenko, Aleksey K. Fedorov","doi":"10.1140/epjqt/s40507-024-00250-0","DOIUrl":"10.1140/epjqt/s40507-024-00250-0","url":null,"abstract":"<div><p>The development of a universal fault-tolerant quantum computer that can solve efficiently various difficult computational problems is an outstanding challenge for science and technology. In this work, we propose a technique for an efficient implementation of quantum algorithms with multilevel quantum systems (qudits). Our method uses a transpilation of a circuit in the standard qubit form, which depends on the characteristics of a qudit-based processor, such as the number of available qudits and the number of accessible levels. This approach provides a qubit-to-qudit mapping and comparison to a standard realization of quantum algorithms highlighting potential advantages of qudits. We provide an explicit scheme of transpiling qubit circuits into sequences of single-qudit and two-qudit gates taken from a particular universal set. We then illustrate our method by considering an example of an efficient implementation of a 6-qubit quantum algorithm with qudits. In this particular example, we demonstrate how using qudits allows a decreasing amount of two-body interactions in the qubit circuit implementation. We expect that our findings are of relevance for ongoing experiments with noisy intermediate-scale quantum devices that operate with information carriers allowing qudit encodings, such as trapped ions and neutral atoms, as well as optical and solid-state systems.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":null,"pages":null},"PeriodicalIF":5.8,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://epjquantumtechnology.springeropen.com/counter/pdf/10.1140/epjqt/s40507-024-00250-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141453557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the bias in iterative quantum amplitude estimation 关于迭代量子振幅估计中的偏差

IF 5.8 2区物理与天体物理

EPJ Quantum Technology Pub Date : 2024-06-25 DOI: 10.1140/epjqt/s40507-024-00253-x

Koichi Miyamoto

{"title":"On the bias in iterative quantum amplitude estimation","authors":"Koichi Miyamoto","doi":"10.1140/epjqt/s40507-024-00253-x","DOIUrl":"10.1140/epjqt/s40507-024-00253-x","url":null,"abstract":"<div><p>Quantum amplitude estimation (QAE) is a pivotal quantum algorithm to estimate the squared amplitude <i>a</i> of the target basis state in a quantum state <span>(|{Phi}rangle )</span>. Various improvements on the original quantum phase estimation-based QAE have been proposed for resource reduction. One of such improved versions is iterative quantum amplitude estimation (IQAE), which outputs an estimate <i>â</i> of <i>a</i> through the iterated rounds of the measurements on the quantum states like <span>(G^{k}|{Phi}rangle )</span>, with the number <i>k</i> of operations of the Grover operator <i>G</i> (the Grover number) and the shot number determined adaptively. This paper investigates the bias in IQAE. Through the numerical experiments to simulate IQAE, we reveal that the estimate by IQAE is biased and the bias is enhanced for some specific values of <i>a</i>. We see that the termination criterion in IQAE that the estimated accuracy of <i>â</i> falls below the threshold is a source of the bias. Besides, we observe that <span>(k_{mathrm{fin}})</span>, the Grover number in the final round, and <span>(f_{mathrm{fin}})</span>, a quantity affecting the probability distribution of measurement outcomes in the final round, are the key factors to determine the bias, and the bias enhancement for specific values of <i>a</i> is due to the skewed distribution of <span>((k_{mathrm{fin}},f_{mathrm{fin}}))</span>. We also present a bias mitigation method: just re-executing the final round with the Grover number and the shot number fixed.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":null,"pages":null},"PeriodicalIF":5.8,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://epjquantumtechnology.springeropen.com/counter/pdf/10.1140/epjqt/s40507-024-00253-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141453554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Continuous variable entanglement between propagating optical modes using optomechanics 利用光力学实现传播光模式之间的连续可变纠缠

IF 5.3 2区物理与天体物理

EPJ Quantum Technology Pub Date : 2024-06-20 DOI: 10.1140/epjqt/s40507-024-00252-y

Greeshma Gopinath, Yong Li, Sankar Davuluri

引用次数: 0

An intelligent threshold selection method to improve orbital angular momentum-encoded quantum key distribution under turbulence 改进湍流条件下轨道角动量编码量子密钥分发的智能阈值选择方法

IF 5.3 2区物理与天体物理

EPJ Quantum Technology Pub Date : 2024-06-06 DOI: 10.1140/epjqt/s40507-024-00251-z

Jia-Hao Li, Jie Tang, Xing-Yu Wang, Yang Xue, Hui-Cun Yu, Zhi-Feng Deng, Yue-Xiang Cao, Ying Liu, Dan Wu, Hao-Ran Hu, Ya Wang, Hua-Zhi Lun, Jia-Hua Wei, Bo Zhang, Bo Liu, Lei Shi

{"title":"An intelligent threshold selection method to improve orbital angular momentum-encoded quantum key distribution under turbulence","authors":"Jia-Hao Li, Jie Tang, Xing-Yu Wang, Yang Xue, Hui-Cun Yu, Zhi-Feng Deng, Yue-Xiang Cao, Ying Liu, Dan Wu, Hao-Ran Hu, Ya Wang, Hua-Zhi Lun, Jia-Hua Wei, Bo Zhang, Bo Liu, Lei Shi","doi":"10.1140/epjqt/s40507-024-00251-z","DOIUrl":"10.1140/epjqt/s40507-024-00251-z","url":null,"abstract":"<div><p>High-dimensional quantum key distribution (HD-QKD) encoded by orbital angular momentum (OAM) presents significant advantages in terms of information capacity. However, perturbations caused by free-space atmospheric turbulence decrease the performance of the system by introducing random fluctuations in the transmittance of OAM photons. Currently, the theoretical performance analysis of OAM-encoded QKD systems exists a gap when concerning the statistical distribution under the free-space link. In this article, we analyzed the security of QKD systems by combining probability distribution of transmission coefficient (PDTC) of OAM with decoy-state BB84 method. To address the problem that the invalid key rate is calculated in the part transmittance interval of the post-processing process, an intelligent threshold method based on neural network is proposed to improve OAM-encoded QKD, which aims to conserve computing resources and enhance system efficiency. Our findings reveal that the ratio of root mean square (RMS) OAM-beam radius to Fried constant plays a crucial role in ensuring secure key generation. Meanwhile, the training error of neural network is at the magnitude around 10<sup>−3</sup>, indicating the ability to predict optimization parameters quickly and accurately. Our work contributes to the advancement of parameter optimization and prediction for free-space OAM-encoded HD-QKD systems. Furthermore, it provides valuable theoretical insights to support the development of free-space experimental setups.</p></div>","PeriodicalId":547,"journal":{"name":"EPJ Quantum Technology","volume":null,"pages":null},"PeriodicalIF":5.3,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://epjquantumtechnology.springeropen.com/counter/pdf/10.1140/epjqt/s40507-024-00251-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141264543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0