研究者詳細 - 林　正人

論文 - 林　正人

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Quantum Private Information Retrieval for Quantum Messages 査読有り国際共著

Song S., Hayashi M.

IEEE International Symposium on Information Theory - Proceedings 2021-July 巻頁： 1052 - 1057 2021年7月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE International Symposium on Information Theory - Proceedings

Quantum private information retrieval (QPIR) for quantum messages is the protocol in which a user retrieves one of the multiple quantum states from one or multiple servers without revealing which state is retrieved. We consider QPIR in two different settings: the blind setting, in which the servers contain one copy of the message states, and the visible setting, in which the servers contain the description of the message states. One trivial solution in both settings is downloading all states from the servers and the main goal of this paper is to find more efficient QPIR protocols. First, we prove that the trivial solution is optimal for one-server QPIR in the blind setting. In one-round protocols, the same optimality holds even in the visible setting. On the other hand, when the user and the server share entanglement, we prove that there exists an efficient one-server QPIR protocol in the blind setting. Furthermore, in the visible setting, we prove that it is possible to construct symmetric QPIR protocols in which the user obtains no information of the non-targeted messages. We construct two-server symmetric QPIR protocols for pure states. Note that symmetric classical PIR is impossible without shared randomness unknown to the user.

DOI： 10.1109/ISIT45174.2021.9517794

Scopus

Physical Layer Computation as NOMA for Integrated Wireless Systems 査読有り国際共著

Hayashi M., Vazquez-Castro A.

IEEE Transactions on Communications 69 巻 ( 7 ) 頁： 4520 - 4535 2021年7月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE Transactions on Communications

We consider two users A and B wanting to exchange their messages M_{A} and M_{B} via a relay in a wireless communication network. To this aim, we have two methods: direct forward (DF) and computation and forward (CAF). In the first method, after an orthogonal multiple access (OMA) or non-orthogonal multiple access (NOMA) phase, the receiver decodes the two messages. In the second method, after a NOMA phase, the receiver decodes only the (modulo) sum. In the latter case the capacity region (computation region) is not known. This paper compares the two methods. To such aim, we propose a unified coding framework and identify a lower bound of achievable computation rates. We consider three constellations for the symmetric two-user Gaussian channel with Eisenstein constellation showing highest performance. We also show that a minimum signal-to-noise ratio is required for our CAF method to outperform DF, and we obtain the numerical values of such minimum ratios for the three constellations. Finally, we show achievability of our bounds, which is proved to require affine codes for computation, which has not been proved before. Overall, our results are useful for communication system designers towards practical implementation of multiple access methods in integrated wireless systems.

DOI： 10.1109/TCOMM.2021.3067907

Scopus

Finite Block Length Analysis on Quantum Coherence Distillation and Incoherent Randomness Extraction 査読有り国際共著

Hayashi M., Fang K., Wang K.

IEEE Transactions on Information Theory 67 巻 ( 6 ) 頁： 3926 - 3944 2021年6月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE Transactions on Information Theory

We give the first systematic study on the second order asymptotics of the operational task of coherence distillation with and without assistance. In the unassisted setting, we introduce a variant of randomness extraction framework where free incoherent operations are allowed before the incoherent measurement and the randomness extractors. We then show that the maximum number of random bits extractable from a given quantum state is precisely equal to the maximum number of coherent bits distillable from the same state. This relation enables us to derive tight second order expansions of both tasks in the independent and identically distributed setting. Remarkably, the incoherent operation classes that can empower coherence distillation for generic states all admit the same second order expansions, indicating their operational equivalence for coherence distillation in both asymptotic and large block length regimes. We then generalize the above line of research to the assisted setting, arising naturally in bipartite quantum systems where Bob distills coherence from the state at hand, aided by the benevolent Alice possessing the other system. More precisely, we introduce a new assisted incoherent randomness extraction task and establish an exact relation between this task and the assisted coherence distillation. It strengthens the one-shot relation in the unassisted setting and confirms that this cryptographic framework offers a new perspective to the study of quantum coherence distillation. Likewise, this relation yields second order characterizations to the assisted tasks. As by-products, we show the strong converse property of the tasks above from their second order expansions.

DOI： 10.1109/TIT.2021.3064009

Scopus

Permutation Enhances Classical Communication Assisted by Entangled States 査読有り国際共著

Wang K., Hayashi M.

IEEE Transactions on Information Theory 67 巻 ( 6 ) 頁： 3905 - 3925 2021年6月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE Transactions on Information Theory

We study classical communication over a noisy quantum channel when bipartite states are preshared between the sender and the receiver, and one of the following encoding strategies are available: i) local operations; ii) local operations and one-way classical communication; iii) local operations and global permutations. Our main result is a capacity formula for strategy iii). This formula's two endpoints are the capacity formula in strategy i) and the entanglement-assisted classical capacity. Interestingly, these capacities satisfy the strong converse property, and thus the formula serves as a sharp dividing line between achievable and unachievable rates of communication. We prove that the difference between the capacities by strategy i) and strategy iii) is upper bounded by the discord of formation of the preshared state. What's more, we show that strategy ii) has no advantage over strategy i) in the weak converse regime. As examples, we derive these capacities analytically by the above strategies for some fundamental quantum channels. In some cases, the capacity of strategy iii) is strictly larger than those of strategies i) and ii) whenever entanglement assistance is available. Our results witness the power of random permutation in entanglement-assisted classical communication.

DOI： 10.1109/TIT.2021.3060452

Scopus

Representation matching for remote quantum computing 査読有り国際共著

Yang Y, Hayashi M

2 巻 2021年5月

Asymptotically Secure Network Code for Active Attacks 査読有り国際共著

Hayashi M., Cai N.

IEEE Transactions on Communications 69 巻 ( 5 ) 頁： 3245 - 3259 2021年5月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE Transactions on Communications

When there exists a malicious attacker in the network, we need to be careful of eavesdropping and contamination. This problem is crucial for network communication when the network is realized by a partially trusted relay of quantum key distribution. We discuss the asymptotic rate in a linear network with the secrecy and robustness conditions when the above type of attacker exists. Also, under the same setting, we discuss the asymptotic rate in a linear network when we impose the secrecy condition alone.

DOI： 10.1109/TCOMM.2021.3057112

Scopus

Secure Computation-and-Forward with Linear Codes 査読有り国際共著

Hayashi M,, Wadayama T., Vazquez-Catro A.

2 巻 2021年3月

Secure non-linear network code over one-hop relay network 査読有り国際共著

Hayashi M, Cai N.

2 巻 2021年3月

Capacity of Quantum Symmetric Private Information Retrieval with Collusion of All But One of Servers 査読有り国際共著

Song S., Hayashi M.

2 巻 2021年3月

Secure Computation-and-Forward with Linear Codes 査読有り国際共著

Hayashi M,, Wadayama T., Vazquez-Catro A.

2 巻 2021年3月

Capacity of Quantum Private Information Retrieval with Multiple Servers 査読有り国際共著

Song S., Hayashi M.

IEEE Transactions on Information Theory 67 巻 ( 1 ) 頁： 452 - 463 2021年1月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE Transactions on Information Theory

We study the capacity of quantum private information retrieval (QPIR) with multiple servers. In the QPIR problem with multiple servers, a user retrieves a classical file by downloading quantum systems from multiple servers each of which contains the copy of a classical file set while the identity of the downloaded file is not leaked to each server. The QPIR capacity is defined as the maximum rate of the file size over the whole dimension of the downloaded quantum systems. When the servers are assumed to share prior entanglement, we prove that the QPIR capacity with multiple servers is 1 regardless of the number of servers and files. We construct a rate-one protocol only with two servers. This capacity-achieving protocol outperforms its classical counterpart in the sense of the capacity, server secrecy, and upload cost. The strong converse bound is derived concisely without using any secrecy condition. We also prove that the capacity of multi-round QPIR is 1.

DOI： 10.1109/TIT.2020.3022515

Scopus

Prior entanglement exponentially improves one-server quantum private information retrieval for quantum messages 査読有り

Song, SH; Gall, FL; Hayashi, M

EPJ QUANTUM TECHNOLOGY 11 巻 ( 1 ) 2024年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：EPJ Quantum Technology

Quantum private information retrieval (QPIR) for quantum messages is a quantum communication task, in which a user retrieves one of the multiple quantum states from the server without revealing which state is retrieved. In the one-server setting, we find an exponential gap in the communication complexities between the presence and absence of prior entanglement in this problem with the one-server setting. To achieve this aim, as the first step, we prove that the trivial solution of downloading all messages is optimal under QPIR for quantum messages, which is a similar result to that of classical PIR but different from QPIR for classical messages. As the second step, we propose an efficient one-server one-round QPIR protocol with prior entanglement by constructing a reduction from a QPIR protocol for classical messages to a QPIR protocol for quantum messages in the presence of prior entanglement.

DOI： 10.1140/epjqt/s40507-024-00266-6

Web of Science

Scopus

Finding the optimal probe state for multiparameter quantum metrology using conic programming 査読有り Open Access

Hayashi, M; Ouyang, YK

NPJ QUANTUM INFORMATION 10 巻 ( 1 ) 2024年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：npj Quantum Information

The ultimate precision in quantum sensing could be achieved using optimal quantum probe states. However, current quantum sensing protocols do not use probe states optimally. Indeed, the calculation of optimal probe states remains an outstanding challenge. Here, we present an algorithm that efficiently calculates a probe state for correlated and uncorrelated measurement strategies. The algorithm involves a conic program, which minimizes a linear objective function subject to conic constraints on a operator-valued variable. Our algorithm outputs a probe state that is a simple function of the optimal variable. We prove that our algorithm finds the optimal probe state for channel estimation problems, even in the multiparameter setting. For many noiseless quantum sensing problems, we prove the optimality of maximally entangled probe states. We also analyze the performance of 3D-field sensing using various probe states. Our work opens the door for a plethora of applications in quantum metrology.

DOI： 10.1038/s41534-024-00905-x

Open Access

Web of Science

Scopus

Asymmetry activation and its relation to coherence under permutation operation 査読有り

Hayashi, M

QUANTUM 8 巻 2024年11月

Reverse em-problem based on Bregman divergence and its application to classical and quantum information theory 査読有り

Hayashi, M

INFORMATION GEOMETRY 7 巻 ( 2 ) 頁： 371 - 440 2024年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Information Geometry

The recent paper (IEEE Trans. IT 69, 1680) proposed an analytical calculation method for the channel capacity without iteration. However, it has restrictions for its application. Also, it does not explain why the channel capacity can be solved analytically in this special case. To expand the applicability of this method, we recall the reverse em-problem, which was proposed by Toyota (Information Geometry, 3, 1355 (2020)) as the repetition of the inverse map of the em iteration to calculate the channel capacity, which is given as the maximum of the mutual information. However, it left several open problems. We formulate the reverse em-problem based on Bregman divergence, and solve these open problems. Using these results, we convert the reverse em-problem into em-problems, and derive a non-iterative formula for the reverse em-problem, which can be considered as a generalization of the above analytical calculation method. Additionally, this derivation explains the information geometrical structure of this special case.

DOI： 10.1007/s41884-024-00147-y

Web of Science

Scopus

Generalized quantum Arimoto-Blahut algorithm and its application to quantum information bottleneck 査読有り Open Access

Hayashi, M; Liu, G

QUANTUM SCIENCE AND TECHNOLOGY 9 巻 ( 4 ) 2024年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Quantum Science and Technology

Quantum information bottleneck was proposed by Grimsmo and Still (2016 Phys. Rev. A 94 012338) as a promising method for quantum supervised machine learning. To study this method, we generalize the quantum Arimoto-Blahut algorithm by Ramakrishnan et al (2021 IEEE Trans. Inf. Theory 67 946) to a function defined over a set of density matrices with linear constraints so that our algorithm can be applied to optimizations of quantum operations. This algorithm has wider applicability, and we apply our algorithm to the quantum information bottleneck with three quantum systems. We numerically compare our obtained algorithm with the existing algorithm by Grimsmo and Still. Our numerical analysis shows that our algorithm is better than their algorithm.

DOI： 10.1088/2058-9565/ad6eb1

Open Access

Web of Science

Scopus

Measurement-device-independent detection of beyond-quantum state 査読有り Open Access

Yu, BC; Hayashi, M

NEW JOURNAL OF PHYSICS 26 巻 ( 10 ) 2024年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：New Journal of Physics

In quantum theory, a quantum state on a composite system of two parties realizes a non-negative probability with any measurement element with a tensor product form. However, there also exist non-quantum states which satisfy the above condition. Such states are called beyond-quantum states, and cannot be detected by standard Bell tests. To distinguish a beyond-quantum state from quantum states, we propose a measurement-device-independent (MDI) test for beyond-quantum state detection, which is composed of quantum input states on respective parties and quantum measurements across the input system and the target system on respective parties. The performance of our protocol is independent of the forms of the tested states and the measurement operators, which provides an advantage in practical scenarios. We also discuss the importance of tomographic completeness of the input sets to the detection.

DOI： 10.1088/1367-2630/ad787c

Open Access

Web of Science

Scopus

Iterative minimization algorithm on a mixture family 査読有り

Hayashi, M

INFORMATION GEOMETRY 2024年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Information Geometry

Iterative minimization algorithms appear in various areas including machine learning, neural networks, and information theory. The em algorithm is one of the famous iterative minimization algorithms in the area of machine learning, and the Arimoto–Blahut algorithm is a typical iterative algorithm in the area of information theory. However, these two topics had been separately studied for a long time. In this paper, we generalize an algorithm that was recently proposed in the context of the Arimoto–Blahut algorithm. Then, we show various convergence theorems, one of which covers the case when each iterative step is done approximately. Also, we apply this algorithm to the target problem of the em algorithm, and propose its improvement. In addition, we apply it to other various problems in information theory.

DOI： 10.1007/s41884-024-00140-5

Web of Science

Scopus

Alexander S. Holevo's researches in quantum information theory in 20th century 査読有り Open Access

Hayashi, M

INTERNATIONAL JOURNAL OF QUANTUM INFORMATION 22 巻 ( 05 ) 2024年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：International Journal of Quantum Information

This paper reviews Holevo's contributions to quantum information theory during the 20 century. At that time, he mainly studied three topics, classical-quantum channel coding, quantum estimation with Craméro-Rao approach and quantum estimation with the group covariant approach. This paper addresses these three topics.

DOI： 10.1142/S0219749924400069

Web of Science

Scopus

Detecting beyond-quantum nonlocality using standard local quantum observables 査読有り

Arai, H; Yu, BC; Hayashi, M

PHYSICAL REVIEW A 110 巻 ( 1 ) 2024年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Review A

We study the detection of beyond-quantum nonlocal states that can exist in a theoretical model whose local systems are standard quantum theory in the framework of general probabilistic theories (GPTs). We find that device-dependent detections are possible for beyond-quantum nonlocal states in GPTs even though device-independent detections are not valid. We give a device-dependent detection based on local observables to distinguish any beyond-quantum nonlocal state from all standard quantum states. In particular, we give a way to detect any beyond-quantum nonlocal state of the two-qubit system by observing only spin observables on local systems. Our results will help in the experimental detection of beyond-quantum nonlocality or justification of standard quantum theory.

DOI： 10.1103/PhysRevA.110.L010201

Web of Science

Scopus

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