Details of the Researcher

PHOTO

Masahiro Hotta
Section
Graduate School of Science
Job title
Assistant Professor
Degree

  • 博士（理学）（東北大学）

e-Rad No.
60261541
Profile
研究テーマ：量子情報物理学
キーワード：量子情報、量子エンタングルメント、ブラックホール、量子エネルギーテレポーテーション

Committee Memberships 2

  • The Royal Society　member of the Society’s Proceedings A Editorial Board

    2014/01 - 2019/12

  • International Society for Relativistic Quantum Information　group leader working on Relativistic Quantum information in the Asian continent

    2014/01 - 2018/12

Papers 50

  1. Probability vector representation of the Schrödinger equation and Leggett-Garg-type experiments Peer-reviewed

    Masahiro Hotta, Sebastian Murk

    Physical Review A　109　062224　2024/06/20

  2. 量子ホール系に量子宇宙を再現する Invited Peer-reviewed

    OYO BUTURI　92　(2)　112-115　2023/02

    DOI： 10.11470/oubutsu.92.2_112 　

  3. Strong chaos of fast scrambling yields order: Emergence of decoupled quantum information capsules Peer-reviewed

    Hotta Masahiro, Yamaguchi Koji

    PHYSICS LETTERS A　384　(3)　2020/01/31

    DOI： 10.1016/j.physleta.2019.126078 　

    ISSN： 0375-9601

  4. Quantum information capsule and information delocalization by entanglement in multiple-qubit systems Peer-reviewed

    Yamaguchi Koji, Watamura Naoki, Hotta Masahiro

    PHYSICS LETTERS A　383　(12)　1255-1259　2019/04/10

    DOI： 10.1016/j.physleta.2019.01.036 　

    ISSN： 0375-9601

  5. Spatially overlapped partners in quantum field theory Peer-reviewed

    Trevison Jose, Yamaguchi Koji, Hotta Masahiro

    JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL　52　(12)　2019/03/22

    DOI： 10.1088/1751-8121/ab065b 　

    ISSN： 1751-8113

  6. Pure state entanglement harvesting in quantum field theory Peer-reviewed

    Trevison Jose, Yamaguchi Koji, Hotta Masahiro

    PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS　(10)　2018/10

    DOI： 10.1093/ptep/pty109 　

    ISSN： 2050-3911

  7. Soft-Hair-Enhanced Entanglement beyond Page Curves in a Black Hole Evaporation Qubit Model Peer-reviewed

    Masahiro Hotta, Yasusada Nambu, Koji Yamaguchi

    Physical Review Letters　120　(18)　2018/05/04

    DOI： 10.1103/PhysRevLett.120.181301 　

    ISSN： 1079-7114 0031-9007

    eISSN： 1079-7114

  8. Transmission and reflection of charge-density wave packets in a quantum Hall edge controlled by a metal gate Peer-reviewed

    Masahiro Matsuura, Takaaki Mano, Takeshi Noda, Naokazu Shibata, Masahiro Hotta, Go Yusa

    APPLIED PHYSICS LETTERS　112　(6)　2018/02

    DOI： 10.1063/1.5009373 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  9. Gravitational memory charges of supertranslation and superrotation on Rindler horizons Peer-reviewed

    Masahiro Hotta, Jose Trevison, Koji Yamaguchi

    PHYSICAL REVIEW D　94　(8)　2016/10

    DOI： 10.1103/PhysRevD.94.083001 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  10. The fall of the black hole firewall: natural nonmaximal entanglement for the Page curve Peer-reviewed

    Masahiro Hotta, Ayumu Sugita

    PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS　(12)　2015/12

    DOI： 10.1093/ptep/ptv170 　

    ISSN： 2050-3911

  11. Partner particles for moving mirror radiation and black hole evaporation Peer-reviewed

    M. Hotta, R. Schützhold, W. G. Unruh

    Physical Review D - Particles, Fields, Gravitation and Cosmology　91　(12)　2015/06/22

    Publisher: American Physical Society

    DOI： 10.1103/PhysRevD.91.124060 　

    ISSN： 1550-2368 1550-7998

  12. Quantum energy teleportation across a three-spin Ising chain in a Gibbs state Peer-reviewed

    Jose Trevison, Masahiro Hotta

    JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL　48　(17)　2015/05

    DOI： 10.1088/1751-8113/48/17/175302 　

    ISSN： 1751-8113

    eISSN： 1751-8121

  13. 量子エネルギーテレポーテーション Invited Peer-reviewed

    堀田昌寛, 遊佐剛

    日本物理学会誌　9　613-622　2014/09

  14. Strong local passivity in finite quantum systems Peer-reviewed

    Michael Frey, Ken Funo, Masahiro Hotta

    PHYSICAL REVIEW E　90　(1)　2014/07

    DOI： 10.1103/PhysRevE.90.012127 　

    ISSN： 1539-3755

    eISSN： 1550-2376

  15. Black hole firewalls require huge energy of measurement Peer-reviewed

    Masahiro Hotta, Jiro Matsumoto, Ken Funo

    PHYSICAL REVIEW D　89　(12)　2014/06

    DOI： 10.1103/PhysRevD.89.124023 　

    ISSN： 1550-7998

    eISSN： 1550-2368

  16. Quantum energy teleportation without a limit of distance Peer-reviewed

    Masahiro Hotta, Jiro Matsumoto, Go Yusa

    PHYSICAL REVIEW A　89　(1)　2014/01

    DOI： 10.1103/PhysRevA.89.012311 　

    ISSN： 1050-2947

    eISSN： 1094-1622

  17. Quantum energy teleportation between spin particles in a Gibbs state Peer-reviewed

    Michael R. Frey, Karl Gerlach, Masahiro Hotta

    Journal of Physics A: Mathematical and Theoretical　46　(45)　2013/11/15

    DOI： 10.1088/1751-8113/46/45/455304 　

    ISSN： 1751-8113 1751-8121

  18. Ground-state-entanglement bound for quantum energy teleportation of general spin-chain models Peer-reviewed

    Masahiro Hotta

    Physical Review A - Atomic, Molecular, and Optical Physics　87　(3)　2013/03/11

    DOI： 10.1103/PhysRevA.87.032313 　

    ISSN： 1050-2947 1094-1622

  19. Ground-state-entanglement bound for quantum energy teleportation of general spin-chain models Peer-reviewed

    Masahiro Hotta

    PHYSICAL REVIEW A　87　(3)　2013/03

    DOI： 10.1103/PhysRevA.87.032313 　

    ISSN： 2469-9926

    eISSN： 2469-9934

  20. Quantum energy teleportation enabled by thermal discord Peer-reviewed

    Michael R. Frey, Masahiro Hotta

    QUANTUM INFORMATION AND COMPUTATION XI　8749　2013

    DOI： 10.1117/12.2012356 　

    ISSN： 0277-786X

  21. Quantum energy teleportation in a quantum Hall system Peer-reviewed

    Go Yusa, Wataru Izumida, Masahiro Hotta

    PHYSICAL REVIEW A　84　(3)　2011/09

    DOI： 10.1103/PhysRevA.84.032336 　

    ISSN： 1050-2947

  22. Passivity breaking of a local vacuum state in a quantum Hall system

    Go Yusa, Wataru Izumida, Masahiro Hotta

    Quantum Physics　1101　2766v1-1-2766v1-4　2011/01/14

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    We propose an experimental method for extracting the zero-point energy from a local vacuum state by performing local operations and classical communication (LOCC). We model a quantum Hall edge channel as a quantum entangled many-body channel and the zero-point fluctuation in the charge density of the channel as the vacuum state. We estimate the order of the energy gain using reasonable experimental parameters. Such a quantum feedback system breaks the passivity of a local vacuum state. It can be used to demonstrate Maxwell's demon or quantum energy teleportation in which no physical entity transports energy.

  23. Quantum energy teleportation with a linear harmonic chain Peer-reviewed

    Yasusada Nambu, Masahiro Hotta

    PHYSICAL REVIEW A　82　(4)　2010/10

    DOI： 10.1103/PhysRevA.82.042329 　

    ISSN： 1050-2947

  24. Energy entanglement relation for quantum energy teleportation Peer-reviewed

    Masahiro Hotta

    PHYSICS LETTERS A　374　(34)　3416-3421　2010/07

    DOI： 10.1016/j.physleta.2010.06.058 　

    ISSN： 0375-9601

  25. Quantum energy teleportation with an electromagnetic field: discrete versus continuous variables Peer-reviewed

    Masahiro Hotta

    JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL　43　(10)　2010/03

    DOI： 10.1088/1751-8113/43/10/105305 　

    ISSN： 1751-8113

  26. Controlled Hawking process by quantum energy teleportation Peer-reviewed

    Masahiro Hotta

    Physical Review D - Particles, Fields, Gravitation and Cosmology　81　(4)　2010/02/16

    DOI： 10.1103/PhysRevD.81.044025 　

    ISSN： 1550-7998 1550-2368

  27. Controlled Hawking process by quantum energy teleportation Peer-reviewed

    Masahiro Hotta

    PHYSICAL REVIEW D　81　(4)　2010/02

    DOI： 10.1103/PhysRevD.81.044025 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  28. Ground-State Entanglement Gives Birth to Quantum Energy Teleportation Peer-reviewed

    Masahiro Hotta

    QUANTUM COMMUNICATION AND QUANTUM NETWORKING　36　66-73　2010

    ISSN： 1867-8211

  29. Quantum energy teleportation with trapped ions Peer-reviewed

    Masahiro Hotta

    PHYSICAL REVIEW A　80　(4)　2009/10

    DOI： 10.1103/PhysRevA.80.042323 　

    ISSN： 1050-2947

  30. Quantum Energy Teleportation in Spin Chain Systems Peer-reviewed

    Masahiro Hotta

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN　78　(3)　2009/03

    DOI： 10.1143/JPSJ.78.034001 　

    ISSN： 0031-9015

  31. Quantum Energy Teleportation Peer-reviewed

    Masahiro Hotta

    QUANTUM COMMUNICATION, MEASUREMENT AND COMPUTING (QCMC)　1110　373-375　2009

    ISSN： 0094-243X

  32. A Protocol of Quantum Authentication with Secure Quantum Passwords Peer-reviewed

    Masahiro Hotta, Masanao Ozawa

    QUANTUM COMMUNICATION, MEASUREMENT AND COMPUTING (QCMC)　1110　388-+　2009

    ISSN： 0094-243X

  33. Quantum measurement information as a key to energy extraction from local vacuums Peer-reviewed

    Masahiro Hotta

    PHYSICAL REVIEW D　78　(4)　2008/08

    DOI： 10.1103/PhysRevD.78.045006 　

    ISSN： 1550-7998

  34. A protocol for quantum energy distribution Peer-reviewed

    Masahiro Hotta

    PHYSICS LETTERS A　372　(35)　5671-5676　2008/08

    DOI： 10.1016/j.physleta.2008.07.007 　

    ISSN： 0375-9601

  35. Channel estimation theory of low-noise multiple parameters: Attainability problem of the Cramér-Rao bounds Peer-reviewed

    M. Hotta, T. Karasawa

    Physical Review A - Atomic, Molecular, and Optical Physics　78　(1)　2008/07/18

    DOI： 10.1103/PhysRevA.78.012332 　

    ISSN： 1050-2947 1094-1622

  36. A fundamental lower bound of actuating energy for broadband photon switching Peer-reviewed

    Masahiro Hotta

    PHYSICS LETTERS A　372　(21)　3752-3758　2008/05

    DOI： 10.1016/j.physleta.2008.02.058 　

    ISSN： 0375-9601

  37. N-body-extended channel estimation for low-noise parameters Peer-reviewed

    M. Hotta, T. Karasawa, M. Ozawa

    Journal of Physics A: Mathematical and General　39　(46)　14465-14470　2006/11/17

    DOI： 10.1088/0305-4470/39/46/015 　

    ISSN： 0305-4470 1361-6447

  38. Ancilla-assisted enhancement of channel estimation for low-noise parameters Peer-reviewed

    Masahiro Hotta, Tokishiro Karasawa, Masanao Ozawa

    Physical Review A - Atomic, Molecular, and Optical Physics　72　(5)　2005/11

    DOI： 10.1103/PhysRevA.72.052334 　

    ISSN： 1050-2947 1094-1622

  39. Complete resolution of the quantum Zeno paradox for outside observers Peer-reviewed

    M. Hotta, M. Morikawa

    Physics Letters, Section A: General, Atomic and Solid State Physics　326　(1-2)　32-41　2004/05/31

    DOI： 10.1016/j.physleta.2004.04.012 　

    ISSN： 0375-9601

  40. Quantum estimation by local observables Peer-reviewed

    Masahiro Hotta, Masanao Ozawa

    Physical Review A - Atomic, Molecular, and Optical Physics　70　(2)　1-223271　2004

    Publisher: American Physical Society

    DOI： 10.1103/PhysRevA.70.022327 　

    ISSN： 1050-2947

  41. Impossibility of distant indirect measurement of the quantum Zeno effect Peer-reviewed

    M. Hotta, M. Morikawa

    Physical Review A - Atomic, Molecular, and Optical Physics　69　(5 A)　1-52114　2004

    Publisher: American Physical Society

    DOI： 10.1103/PhysRevA.69.052114 　

    ISSN： 1050-2947

  42. Holographic charge excitation on a horizontal boundary Peer-reviewed

    M. Hotta

    Physical Review D - Particles, Fields, Gravitation and Cosmology　66　(12)　2002

    DOI： 10.1103/PhysRevD.66.124021 　

    ISSN： 1550-2368 1550-7998

  43. Toward generalized entropy composition with different q indices and H-theorem Peer-reviewed

    Kenichi Sasaki, Masahiro Hotta

    Journal of the Physical Society of Japan　69　(12)　3830-3839　2000

    Publisher: Physical Society of Japan

    DOI： 10.1143/JPSJ.69.3830 　

    ISSN： 0031-9015

  44. Composability and generalized entropy Peer-reviewed

    M. Hotta, I. Joichi

    Physics Letters, Section A: General, Atomic and Solid State Physics　262　(4-5)　302-309　1999

    Publisher: Elsevier

    DOI： 10.1016/S0375-9601(99)00678-7 　

    ISSN： 0375-9601

  45. Quantum system under periodic perturbation: Effect of environment Peer-reviewed

    M. Hotta, I. Joichi, Sh. Matsumoto, M. Yoshimura

    Physical Review D - Particles, Fields, Gravitation and Cosmology　55　(8)　4614-4639　1997

    DOI： 10.1103/PhysRevD.55.4614 　

    ISSN： 1550-2368 1550-7998

  46. Geometric bremsstrahlung in the early Universe Peer-reviewed

    Toshifumi Futamase, Masahiro Hotta, Hajime Inoue, Masahiro Yamaguchi

    Progress of Theoretical Physics　96　(1)　113-123　1996

    Publisher: Yukawa Institute for Theoretical Physics

    DOI： 10.1143/PTP.96.113 　

    ISSN： 0033-068X

  47. High momentum behavior of geometric bremsstrahlung in the expanding universe Peer-reviewed

    Masahiro Hotta, Hajime Inoue, Izumi Joichi, Masahiro Tanaka

    Progress of Theoretical Physics　96　(6)　1103-1122　1996

    Publisher: Yukawa Institute for Theoretical Physics

    DOI： 10.1143/PTP.96.1103 　

    ISSN： 0033-068X

  48. Field theory of anyons and the fractional quantum Hall effect Peer-reviewed

    Z. F. Ezawa, M. Hotta, A. Iwazaki

    Physical Review B　46　(12)　7765-7781　1992

    DOI： 10.1103/PhysRevB.46.7765 　

    ISSN： 0163-1829

  49. Imported Symmetry and Two Breathing Modes in Chern-Simons Theory with External Magnetic Field : Particles and Fields

    Masahiro HOTTA, Department of Physics Tohoku University

    Progress of theoretical physics = Progress of theoretical physics　86　(6)　1289-1299　1991/12/25

    Publisher:

    DOI： 10.1143/PTP.86.1289 　

    ISSN： 0033-068x

  50. Breathing vortex solitons in nonrelativistic Chern-Simons gauge theory Peer-reviewed

    Z. F. Ezawa, M. Hotta, A. Iwazaki

    Physical Review Letters　67　(4)　411-414　1991

    DOI： 10.1103/PhysRevLett.67.411 　

    ISSN： 0031-9007

Show all ︎Show first 5

Misc. 18

  1. The final burst of the moving mirror is unrelated to the partner mode of analog Hawking radiation Peer-reviewed

    Yuki Osawa, Kuan-Nan Lin, Yasusada Nambu, Masahiro Hotta, Pisin Chen

    Physica Review D　110　025023　2024/04/15

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    Flying mirrors with appropriate trajectories have been recognized as an analog system that mimics black hole Hawking evaporation and have been widely investigated. It has recently been suggested that the partner mode of the analog Hawking radiation emitted from a moving mirror would manifest itself through a final burst when the mirror executes a sudden stop. Here we argue the opposite via the partner formula for the moving mirror model. By expanding the theoretical foundation of the partner formula and augmenting it with numerical analysis, we demonstrate that the supposed final burst is induced by a shock that requires the input of external energy, whereas the Hawking radiation partner mode, which is associated with the zero-point vacuum fluctuations, is not responsible for the burst.

  2. Probability vector representation of the Schrödinger equation and noninvasive measurability for Leggett-Garg inequalities

    Masahiro Hotta, Sebastian Murk

    2023/12/26

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    Leggett-Garg inequalities place bounds on the temporal correlations of a system based on the principles of macroscopic realism (MR) and noninvasive measurability (NM). Their conventional formulation relies on the ensemble-averaged products of observables measured at different instants of time. However, this expectation value based approach does not provide a clear definition of NM. A complete description that enables a precise understanding and captures all physically relevant features requires the study of probability distributions associated with noncommuting observables. In this article, we propose a scheme to describe the dynamics of generic $N$-level quantum systems via a probability vector representation of the Schr\"odinger equation and define a precise notion of NM for the probability distributions of noncommuting observables. This allows us to elucidate MR itself more clearly, eliminating any potential confusion. In addition, we introduce a measure to quantify violations of NM for arbitrary quantum states. For single-qubit systems, we pinpoint the pivotal relation that establishes a connection between the disturbance of observables incurred during a measurement and the resulting NM violation.

  3. Analog de Sitter universe in quantum Hall systems with an expanding edge Peer-reviewed

    Yasusada Nambu, Masahiro Hotta

    Physica Review D　107　085002　2023/01/23

    DOI： 10.1103/PhysRevD.107.085002 　

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    Expanding edges in quantum Hall systems can become a simulator of quantum 1+1 dimensional expanding universes. In these systems, edge exciations are represented as a chiral scalar field in curved spacetimes. We investigate Hawking radiation and entanglement behavior predicted by this model assuming that the expansion law of the edge region corresponds to a de Sitter universe. As observable quantities for the quantum field, local spatial modes associated with detection regions are introduced using window functions for the field, and their correlations are evaluated. We found impact of Hawking radiation caused by the edge expansion on auto-correlation functions of the local modes, and confirmed that entanglement death due to Hawking radiation occurs. This behavior of entanglement is related to ``quantum to classical transition" in cosmic inflations.

  4. Limitations of Quantum Measurements and Operations of Scattering Type under the Energy Conservation Law

    Ryota Katsube, Masanao Ozawa, Masahiro Hotta

    arXiv:2211.13433 [quant-ph]　2022/11/28

    DOI： 10.48550/arXiv.2211.13433 　

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    It is important to improve the accuracy of quantum measurements and operations both in engineering and fundamental physics. It is known, however, that the achievable accuracy of measurements and unitary operations are generally limited by conservation laws according to the Wigner-Araki-Yanase theorem (WAY theorem) and its generalizations. Although many researches have extended the WAY theorem quantitatively, most of them, as well as the original WAY theorem, concern only additive conservation laws like the angular momentum conservation law. In this paper, we explore the limitation incurred by the energy conservation law, which is universal but is one of the non-additive conservation laws. We present a lower bound for the error of a quantum measurement using a scattering process satisfying the energy conservation law. We obtain conditions that a control system Hamiltonian must fulfill in order to implement a controlled unitary gate with zero error when a scattering process is considered. We also show the quantitative relationship between the upper bound of the gate fidelity of a controlled unitary gate and the energy fluctuation of systems when a target system and a control system are both one qubit.

  5. Deep Learning Metric Detectors in General Relativity

    Ryota Katsube, Wai-Hong Tam, Masahiro Hotta, Yasusada Nambu

    2022/06/07

    DOI： 10.1103/PhysRevD.106.044051 　

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    We consider conceptual issues of deep learning (DL) for metric detectors using test particle geodesics in curved spacetimes. Advantages of DL metric detectors are emphasized from a view point of general coordinate transformations. Two given metrics (two spacetimes) are defined to be conneted by a DL isometry if their geodesic image data cannot be discriminated by any DL metric detector at any time. The fundamental question of when the DL isometry appears is extensively explored. If the two spacetimes connected by the DL isometry are in superposition of quantum gravity theory, the post-measurement state may be still in the same superposition even after DL metric detectors observe the superposed state. We also demonstrate metric-detection DL's in 2+1 dimensional anti-de Sitter (AdS) spacetimes to estimate the cosmological constants and Brown-Henneaux charges. In the AdS/CFT correspondence dictionary, it may be expected that such metric detectors in the AdS bulk region correspond to quantum measurement devices in the CFT at the AdS boundary.

  6. Expanding Edges of Quantum Hall Systems in a Cosmology Language -- Hawking Radiation from de Sitter Horizon in Edge Modes

    Masahiro Hotta, Yasusada Nambu, Yuuki Sugiyama, Kazuhiro Yamamoto, Go Yusa

    2022/02/08

    DOI： 10.1103/PhysRevD.105.105009 　

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    Expanding edge experiments are promising to open new physics windows of quantum Hall systems. In a static edge, the edge excitation, which is described by free fields decoupled with the bulk dynamics, is gapless, and the dynamics preserve conformal symmetry. When the edge expands, such properties need not be preserved. We formulate a quantum field theory in 1+1 dimensional curved spacetimes to analyze the edge dynamics. We propose methods to address the following questions using edge waveforms from the expanding region: Does the conformal symmetry survive? Is the nonlinear interaction of the edge excitations induced by edge expansion? Do the edge excitations interact with the bulk excitations? We additionally show that the expanding edges can be regarded as expanding universe simulators of two-dimensional dilaton-gravity models, including the Jackiw-Teitelboim gravity model. As an application, we point out that our theoretical setup might simulate emission of analog Hawking radiation with the Gibbons-Hawking temperature from the future de Sitter horizon formed in the expanding edge region.

  7. Comment on "When the Quantum Energy Teleportation is Observable? "

    Masahiro Hotta

    2021/06/25

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    Recently authors of a paper (arXiv:2105.04407) claim that quantum energy teleportation is unobservable due to a time-energy uncertainty relation. In this short note, I will point out that their argument is wrong. They misuse the uncertainty relation.

  8. A Lie algebra based approach to asymptotic symmetries in general relativity

    Takeshi Tomitsuka, Koji Yamaguchi, Masahiro Hotta

    2020/12/28

    DOI： 10.1088/1361-6382/ac2c1e 　

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    Asymptotic symmetries of black hole spacetimes have received much attention as a possible origin of the Bekenstein-Hawking entropy in black hole thermodynamics. In general, it takes hard efforts to find appropriate asymptotic conditions on a metric and a Lie algebra generating the transformation of symmetries with which the corresponding charges are integrable. We here propose an alternative approach to construct building blocks of asymptotic symmetries of a given spacetime metric. Our algorithmic approach may make it easier to explore asymptotic symmetries in any spacetime than in conventional approaches. As an explicit application, we analyze the asymptotic symmetries on Rindler horizon. We find a new class of symmetries related with dilatation transformations in time and in the direction perpendicular to the horizon, which we term superdilatations.

  9. Duality in the dynamics of Unruh-DeWitt detectors in conformally related spacetimes

    Masahiro Hotta, Achim Kempf, Eduardo Martín-Martínez, Takeshi Tomitsuka, Koji Yamaguchi

    2020/02/03

    DOI： 10.1103/PhysRevD.101.085017 　

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    We prove a nonperturbative duality concerning the dynamics of harmonic-oscillator-type Unruh-DeWitt detectors in curved spacetimes. Concretely, using the Takagi transformation we show that the action of a harmonic oscillator Unruh-DeWitt detector with one frequency in a spacetime is equal to that of a detector with a different frequency in a conformally related spacetime. As an example, we show that the dynamics of simple stationary detectors in flat spacetime is dual to that of detectors in a cosmological scenario. The nonperturbative duality enables us to investigate entanglement harvesting in new scenarios in curved spacetime by using results obtained in simpler, conformally related spacetimes.

  10. A Fundamental Upper Bound for Signal to Noise Ratio of Quantum Detectors

    Ryota Katsube, Masahiro Hotta, Koji Yamaguchi

    2019/10/11

    DOI： 10.7566/JPSJ.89.054005 　

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    Quantum fluctuations yield inevitable noises in quantum detection. We derive an upper bound of signal to noise ratio for arbitrary quantum detection described by trace-class operators with discrete spectra. The bound is independent of observables to be detected and is computed by quantum fidelity of two initial quantum states. We provide applications of the upper bound.

  11. Partner formula for an arbitrary moving mirror in $1+1$ dimensions

    Takeshi Tomitsuka, Koji Yamaguchi, Masahiro Hotta

    2019/06/12

    DOI： 10.1103/PhysRevD.101.024003 　

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    In the information loss problem in black hole evaporation, investigation of the purification partner of a Hawking particle is crucial. It is a well-known fact that 3+1 dimensional spherically symmetric gravitational collapse can be approximately described by 1+1 dimensional moving mirror models. Since a detected particle in field theory is defined by what a particle detector observes, the diversity of detector designs yields a variety of particles and their partners. We provide a formula of generalized partners of detected particles emitted out of mirrors in arbitrary motion in a free massless scalar field theory. Using the formula, we directly demonstrate information storage about pre-thermal information in a pure state of a Hawking particle and its partner. The partner form drastically changes depending on the detailed designs of particle detectors for the Hawking radiation. In a case of the Hawking particle and its partner sensitive to information about pre-thermal era, spatial configurations of the partner has long tails in a stage where only zero-point fluctuation is emitted out of the mirror.

  12. Quantum Information Capsule in Multiple-Qudit Systems and Continuous-Variable Systems

    Koji Yamaguchi, Masahiro Hotta

    2019/02/15

    DOI： 10.1016/j.physleta.2020.126447 　

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    Quantum correlations in an entangled many-body system are capable of storing information. Even when the information is injected by a local unitary operation to the system, the entanglement delocalizes it. In a recent study on multiple-qubit systems, it is shown that a virtual qubit defined in the correlation space plays a role of perfect storage of delocalized information, which is called a quantum information capsule (QIC). In order to enhance the capacity of quantum information storage, it is crucial to formulate the cases for multiple-qudit systems and continuous-variable (CV) systems. We analytically prove that it is possible to construct a QIC for general write operations of the systems. It turns out that the extension to quantum field theory is achievable. For Gaussian states, we explicitly construct a QIC for shift write operations. We analyze the time-evolution of QIC in a CV system to demonstrate the diffusion of information in entangled pure states.

  13. 量子ホールエッジにおける量子エネルギーテレポーテーションの試み

    松浦雅広, 野田武司, 間野高明, 柴田尚和, 堀田昌寛, 遊佐剛

    日本物理学会講演概要集(CD-ROM)　72　(2)　2017

    ISSN： 2189-079X

  14. Quantum Energy Teleportation

    Hotta Masahiro, Yusa Go

    69　(9)　613-622　2014/09

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 0029-0181

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    Nothingness is not empty in physics. It stands for the vacuum state of quantum fields with spatially entangled zero-point fluctuation. The vacuum entanglement allows for quantum protocols which attain energy transportation using only local operations and classical communication in an operational meaning. Thus the protocol is referred to as quantum energy teleportation (QET). QET is expected to be implemented by using quantum Hall edge currents. QET also sheds new light on the information loss problem of black hole evaporation.

  15. Quantum Energy Teleportation: An Introductory Review

    Masahiro Hotta

    2011/01/20

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    The development of techniques for manipulation of quantum information has opened the door to a variety of protocols for accomplishing unprecedented tasks. In particular, a new protocol of quantum teleportation was proposed in 2008 to achieve effective energy transportation simply via local operations and classical communication without breaking any known physical laws. This is achieved by extracting zero-point energy of entangled many-body systems by local operations dependent on information obtained by a distant measurement. The concept is reviewed from an introductory viewpoint herein.

  16. A Brief Introduction to Quantum Energy Teleportation

    Masahiro Hotta

    2010/08/01

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    A new quantum protocol is introduced which attains energy transportation only by local operations and classical communication retaining all physical laws including local energy conservation.

  17. Secure Quantum Passwords

    Masahiro Hotta, Masanao Ozawa

    2008/06/06

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    We propose a quantum authentication protocol that is robust against the theft of secret keys. In the protocol, disposable quantum passwords prevent impersonation attacks with stolen secret keys. The protocol also prevents the leakage of secret information of a certification agent.

  18. Asymptotic Isometry and Two Dimensional Anti-de Sitter Gravity

    Masahiro Hotta

    1998/09/09

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    We analyze canonical asymptotic isometry of two dimensional AdS dilaton gravity in detail.

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Books and Other Publications 1

  1. 量子情報と時空の物理

    堀田昌寛

    サイエンス社　2014/01

Presentations 8

  1. 量子エネルギーテレポーテーションの最近の進展 Invited

    堀田昌寛

    第51回量子情報技術研究会　2024/11/28

  2. Particle detectors and purification partners for the observed particles Invited

    Masahiro Hotta

    2024/08/07

  3. Particle detectors and purification partners for the observed particles Invited

    Masahiro Hotta

    Golden Wedding of Black Holes and Thermodynamics　2023/12/05

  4. SOFT-HAIR-ENHANCED ENTANGLEMENT BEYOND PAGE CURVES IN A BLACK-HOLE EVAPORATION QUBIT MODEL Invited

    Masahiro Hotta

    12th Relativistic Quantum Information Workshop (University of Queensland, Australia)　2019/02/22

  5. Soft-hair enhanced entanglement beyond Page curves in a black-hole evaporation qubit model Invited

    Masahiro Hotta

    The Relativistic Quantum Information Workshop (Korea, Seoul)　2018/07/16

  6. Entanglement Beyond Page Curves in Black-Hole Evaporation Qubit Models Invited

    Masahiro Hotta

    Third LeCosPA International Symposium, Cosmic Prospects（National Taiwan University, Taiwan）　2017/11/27

  7. Horizontal Charge Excitation of Supertranslation and Superrotation Invited

    Masahiro Hotta

    Relativistic Quantum Information-North 2016 (University of Waterloo, Canada)　2016/06/21

  8. The Fall of the Black Hole Firewall: Natural Non-Maximal Entanglement for the Page Curve Invited

    Masahiro Hotta

    Relativistic Quantum Information-North (Dartmouth College, USA)　2015/07/05

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Research Projects 1

  1. ブラックホールの量子情報物理学的研究 Competitive

    堀田昌寛

    Offer Organization: 日本学術振興会

    System: 基盤研究C

    2017/04 - 2019/03