Butsuri
Online ISSN : 2423-8872
Print ISSN : 0029-0181
ISSN-L : 0029-0181
Volume 74 , Issue 10
Showing 1-19 articles out of 19 articles from the selected issue
Preface
Contents
Reviews
Researches
  • Yuho Sakatani
    Type: Researches
    2019 Volume 74 Issue 10 Pages 709-713
    Published: October 05, 2019
    Released: March 10, 2020
    JOURNAL FREE ACCESS

    Type II string theory compactified on a torus has the T-duality symmetry. It is a very powerful symmetry but not manifest in the conventional formulation. Double Field Theory (DFT) is a new formulation of supergravity which manifests the T-duality symmetry. In DFT, we introduce an extended space, called the doubled space, and geometry on the doubled space gives a nice description of backgrounds arising in string theory. We explain the geometry of the doubled space and applications of DFT.

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  • Shinji Miwa, Motohiro Suzuki, Masahito Tsujikawa, Takayuki Nozaki
    Type: Researches
    2019 Volume 74 Issue 10 Pages 714-719
    Published: October 05, 2019
    Released: March 10, 2020
    JOURNAL FREE ACCESS

    Electric-field control of magnetic properties at room temperature has attracted much attention because of its great potential for ultralow-power-consumption electric and spintronic devices. Recently, the electric field effect has been observed not only in semiconductor-based devices but also in metallic ones. In this article, we introduce an electric field effect on interfacial magnetism, specifically, interfacial magnetic anisotropy of ferromagnetic metals. We review experimental studies to reveal the microscopic origin of the electric-field-induced effect using X-ray magnetic circular dichroism spectroscopy.

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  • Kosuke Fukui, Akihisa Tomita, Atsushi Okamoto, Keisuke Fujii
    Type: Researches
    2019 Volume 74 Issue 10 Pages 720-726
    Published: October 05, 2019
    Released: March 10, 2020
    JOURNAL FREE ACCESS

    To implement large-scale quantum computation, the Gottesman-Kitaev-Preskill (GKP) qubit has been recognized as an important technological element. However, it is still challenging to experimentally generate the GKP qubit with the required squeezing level for large-scale quantum computation. To reduce this requirement, we develop a method to prevent the squeezing level from decreasing during the construction of the large-scale cluster. We show that our method with the analog quantum error correction can relax the required squeezing level within the reach of the current experimental technology.

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  • Takafumi Niida, ShinIchi Esumi
    Type: Researches
    2019 Volume 74 Issue 10 Pages 727-732
    Published: October 05, 2019
    Released: March 10, 2020
    JOURNAL FREE ACCESS

    The matter created in non-central heavy-ion collisions should have an initial orbital angular momentum carried by the two colliding nuclei. This angular momentum would be partially transferred to the spin of produced particles due to spin-orbit coupling, leading to the global polarization. The STAR Collaboration observed global polarizations of Λ and Λ(¯) hyperons in Au+Au collisions for collision energies of √SNN=7.7–200 GeV, indicating the creation of the most vortical fluid ever observed, with vorticity of the order of ω~1022 s-1. In this article, we review recent results on the polarization measurements and discuss the physics implications.

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