Faculty Profiles - HAYASHI Masahito

Papers - HAYASHI Masahito

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Quantum Private Information Retrieval for Quantum Messages Reviewed International coauthorship

IEEE International Symposium on Information Theory - Proceedings Vol. 2021-July page： 1052 - 1057 2021.7

Physical Layer Computation as NOMA for Integrated Wireless Systems Reviewed International coauthorship

Hayashi M., Vazquez-Castro A.

IEEE Transactions on Communications Vol. 69 ( 7 ) page： 4520 - 4535 2021.7

Permutation Enhances Classical Communication Assisted by Entangled States Reviewed International coauthorship

IEEE Transactions on Information Theory Vol. 67 ( 6 ) page： 3905 - 3925 2021.6

Finite Block Length Analysis on Quantum Coherence Distillation and Incoherent Randomness Extraction Reviewed International coauthorship

Hayashi M., Fang K., Wang K.

IEEE Transactions on Information Theory Vol. 67 ( 6 ) page： 3926 - 3944 2021.6

Representation matching for remote quantum computing Reviewed International coauthorship

Yang Y, Hayashi M

PRX Quantum Vol. 2 2021.5

Asymptotically Secure Network Code for Active Attacks Reviewed International coauthorship

Hayashi M., Cai N.

IEEE Transactions on Communications Vol. 69 ( 5 ) page： 3245 - 3259 2021.5

Secure Computation-and-Forward with Linear Codes Reviewed International coauthorship

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

IEEE Journal on Selected Areas in Information Theory Vol. 2 2021.3

Secure non-linear network code over one-hop relay network Reviewed International coauthorship

Hayashi M, Cai N.

IEEE Journal on Selected Areas in Information Theory Vol. 2 2021.3

Capacity of Quantum Symmetric Private Information Retrieval with Collusion of All But One of Servers Reviewed International coauthorship

Song S., Hayashi M.

IEEE Journal on Selected Areas in Information Theory Vol. 2 2021.3

Secure Computation-and-Forward with Linear Codes Reviewed International coauthorship

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

IEEE Journal on Selected Areas in Information Theory Vol. 2 2021.3

Capacity of Quantum Private Information Retrieval with Multiple Servers Reviewed International coauthorship

IEEE Transactions on Information Theory Vol. 67 ( 1 ) page： 452 - 463 2021.1

Prior entanglement exponentially improves one-server quantum private information retrieval for quantum messages Reviewed

Song, SH; Gall, FL; Hayashi, M

EPJ QUANTUM TECHNOLOGY Vol. 11 ( 1 ) 2024.12

Language：English Publishing type：Research paper (scientific journal) Publisher：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 Reviewed Open Access

Hayashi, M; Ouyang, YK

NPJ QUANTUM INFORMATION Vol. 10 ( 1 ) 2024.11

Language：English Publishing type：Research paper (scientific journal) Publisher：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 Reviewed

Hayashi, M

QUANTUM Vol. 8 2024.11

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

Hayashi, M

INFORMATION GEOMETRY Vol. 7 ( 2 ) page： 371 - 440 2024.11

Language：English Publishing type：Research paper (scientific journal) Publisher：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 Reviewed Open Access

Hayashi, M; Liu, G

QUANTUM SCIENCE AND TECHNOLOGY Vol. 9 ( 4 ) 2024.10

Language：English Publishing type：Research paper (scientific journal) Publisher：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 Reviewed Open Access

Yu, BC; Hayashi, M

NEW JOURNAL OF PHYSICS Vol. 26 ( 10 ) 2024.10

Language：English Publishing type：Research paper (scientific journal) Publisher：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 Reviewed

Hayashi, M

INFORMATION GEOMETRY 2024.8

Language：English Publishing type：Research paper (scientific journal) Publisher：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 Reviewed Open Access

Hayashi, M

INTERNATIONAL JOURNAL OF QUANTUM INFORMATION Vol. 22 ( 05 ) 2024.8

Language：English Publishing type：Research paper (scientific journal) Publisher：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 Reviewed

Arai, H; Yu, BC; Hayashi, M

PHYSICAL REVIEW A Vol. 110 ( 1 ) 2024.7

Language：English Publishing type：Research paper (scientific journal) Publisher：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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Papers - HAYASHI Masahito