Butsuri
Online ISSN : 2423-8872
Print ISSN : 0029-0181
ISSN-L : 0029-0181
Volume 76 , Issue 10
Showing 1-17 articles out of 17 articles from the selected issue
Preface
Contents
Topics
Overview Articles
  • Yuki Takeuchi
    Type: Overview Articles
    2021 Volume 76 Issue 10 Pages 628-636
    Published: October 05, 2021
    Released: October 05, 2021
    JOURNAL RESTRICTED ACCESS

    Measurement-based quantum computation (MBQC) is one of promising quantum-computing models. The model provides us novel insights into quantum computation. In this article, we explain the basics of MBQC and give some recent progress on it. Particularly, we focus on studies toward reducing the number of measurements required to perform MBQC. Our recent result shows that two Pauli-basis measurements are sufficient for both MBQC and its verification. It could facilitate the realization of fault-tolerant universal quantum computers.

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  • Teruaki Enoto, Nobutoshi Yasutake
    Type: Overview Articles
    2021 Volume 76 Issue 10 Pages 637-645
    Published: October 05, 2021
    Released: October 05, 2021
    JOURNAL RESTRICTED ACCESS

    The equation of state inside neutron stars is an important unsolved problem in modern physics. Astronomical observations to measure the mass and radius of neutron stars provide essential information of the high-density region that cannot be tested by ground-based nuclear experiments. In this review, we report on the current status of solving the equation of state, which has been narrowed down by the latest results from the NICER X-ray observatory, radio observations of pulsars, nuclear experiments, and gravitational wave observations.

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Researches
  • Yoshihiko Togawa
    Type: Researches
    2021 Volume 76 Issue 10 Pages 646-651
    Published: October 05, 2021
    Released: October 05, 2021
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    A role of chirality in crystals are discussed in terms of an emergence of macroscopic spin response, being inspired by recent works on chiral magnetism and chirality-induced spin polarization.

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  • Ryo Tamura, Masashi Hase, Koji Hukushima
    Type: Researches
    2021 Volume 76 Issue 10 Pages 652-657
    Published: October 05, 2021
    Released: October 05, 2021
    JOURNAL RESTRICTED ACCESS

    We propose a data-driven technique to estimate a Hamiltonian with error bars which can explain experimentally observed physical properties. Our method is based on Bayesian inference, and the posterior distribution depending on the parameters in the Hamiltonian is introduced. To effectively search for a better maximizer of posterior distribution, a Bayesian optimization can be applied. As a demonstration, using our technique, a spin Hamiltonian of KCu4P3O12 is determined from the experimentally observed magnetic susceptibility and magnetization curves with various temperatures under high magnetic fields. The estimated spin Hamiltonian is useful to predict hard-to-measure properties such as spin gap and magnetic entropy.

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  • Daigorou Hirai, Zenji Hiroi
    Type: Researches
    2021 Volume 76 Issue 10 Pages 658-662
    Published: October 05, 2021
    Released: October 05, 2021
    JOURNAL RESTRICTED ACCESS

    Transition metal compounds sometimes exhibit attractive colors. These colors usually come from the excitation of the d-electrons by absorbing light. Unique d-orbital states may result in novel optical properties. A new 5d oxychloride, Ca3ReO5Cl2, shows unusually distinct pleochroism; that is, the material exhibits different colors depending on the viewing direction. The key to realizing this unique optical property is found to be the mixed-anion coordination of the 5d rhenium ion, where five oxide ions are pyramidally coordinated and one chloride ion is located on the opposite side. This coordination activates the Laporute forbidden d d transition and leads to non-degenerate 5d levels due to the complex crystal field. These features lead to polarization-dependent excitation of d-electrons, which is observed as pleochroism. The present results demonstrate that compounds containing more than one anionic species, called mixed-anion compounds, may have novel properties inaccessible to a single-anion analog owing to the characteristic crystal and electronic structures.

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  • Takashi Uneyama
    Type: Researches
    2021 Volume 76 Issue 10 Pages 663-668
    Published: October 05, 2021
    Released: October 05, 2021
    JOURNAL RESTRICTED ACCESS

    Soft matters often exhibit complex random motions (Brownian motions) at the mesoscopic scale. Due to the internal degrees of freedom and interaction, the mesoscopic dynamics can be rather complex. To describe such complex dynamics, we need to reduce the degrees of freedom of target systems (the coarse-graining). Conventionally, the projection operator method and the generalized Langevin equation have been utilized to describe such dynamics. Recently, other coarse-graining methods have been proposed where the diffusion coefficients and potentials are treated as time-dependent and fluctuating quantities. The fluctuating diffusion coefficients and potentials enable us to express complex random dynamics of soft matters with relatively simple dynamic equation models. We show basic concepts and some applications of fluctuating diffusion coefficients and potentials.

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