Hayata, Tomoya

写真a

Affiliation

School of Medicine (Hiyoshi)

Position

Associate Professor (Non-tenured)
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Papers 【 Display / hide 】

  • Dense QCD<inf>2</inf> with matrix product states

    Hayata T., Hidaka Y., Nishimura K.

    Journal of High Energy Physics 2024 ( 7 )  2024.07

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    We study one-flavor SU(2) and SU(3) lattice QCD in (1 + 1) dimensions at zero temperature and finite density using matrix product states and the density matrix renormalization group. We compute physical observables such as the equation of state, chiral condensate, and quark distribution function as functions of the baryon number density. As a physical implication, we discuss the inhomogeneous phase at nonzero baryon density, where the chiral condensate is inhomogeneous, and baryons form a crystal. We also discuss how the dynamical degrees of freedom change from hadrons to quarks through the formation of quark Fermi seas.

  • Non-Hermitian p -wave superfluid and effects of the inelastic three-body loss in a one-dimensional spin-polarized Fermi gas

    Tajima H., Sekino Y., Inotani D., Dohi A., Nagataki S., Hayata T.

    Physical Review Research 6 ( 2 )  2024.04

    ISSN  26431564

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    We theoretically investigate non-Hermitian p-wave Fermi superfluidity in one-dimensional spin-polarized Fermi gases which is relevant to recent ultracold atomic experiments. Considering an imaginary atom-dimer coupling responsible for the three-body recombination process in the Lindblad formalism, we discuss the stability of the superfluid state against the atomic loss effect. Within the two-channel non-Hermitian BCS-Eagles-Leggett theory, the atomic loss is characterized by the product of the imaginary atom-dimer coupling and the p-wave effective range. Our results indicate that for a given imaginary atom-dimer coupling, a smaller magnitude of the effective ranges of p-wave interaction is crucial for reaching the non-Hermitian p-wave Fermi superfluid state. Moreover, our theoretical framework for many-body systems with the three-body loss, which is inevitable in ultracold atoms, would promote further progress in non-Hermitian cold-atomic physics.

  • Two-dimensional lattice with an imaginary magnetic field

    Ozawa T., Hayata T.

    Physical Review B 109 ( 8 )  2024.02

    ISSN  24699950

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    We introduce a two-dimensional non-Hermitian lattice model with an imaginary magnetic field and elucidate various unique features which are absent in Hermitian lattice models with real magnetic fields. To describe the imaginary magnetic field, we consider both the Landau gauge and the symmetric gauge, which are related by a generalized gauge transformation, changing not only the phase but also the amplitude of the wave function. We discuss the complex energy spectrum and the non-Hermitian Aharonov-Bohm effect as examples of properties which are due to the imaginary magnetic field independent of the generalized gauge transformation. We show that the energy spectrum does not converge as the lattice size is made larger, which comes from the intrinsic nonperiodicity of the model. However, we have found that the energy spectrum does converge if one fixes the length of one side and makes the other side longer; this asymptotic behavior can be understood in the framework of the non-Bloch band theory. We also find an analog of the Aharonov-Bohm effect; the net change of the norm of the wave function upon adiabatically forming a closed path is determined by the imaginary magnetic flux enclosed by the path, which provides an experimentally observable feature of the imaginary magnetic field.

  • Dynamical chirality production in one dimension

    Hayata T., Nakayama K., Yamamoto A.

    Physical Review D 109 ( 3 )  2024.02

    ISSN  24700010

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    We discuss the quantum computation of dynamical chirality production in lattice gauge theory. Although the chirality of a lattice fermion is complicated in general dimensions, it can be simply formulated on a one-dimensional lattice. The chiral fermion formalism enables us to extract the physical part of the chirality production that would be interpreted as the chiral anomaly in the continuous theory. We demonstrate the computation of the Z2 lattice gauge theory on a classical emulator.

  • q deformed formulation of Hamiltonian SU(3) Yang-Mills theory

    Hayata T., Hidaka Y.

    Journal of High Energy Physics 2023 ( 9 )  2023.09

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    We study SU(3) Yang-Mills theory in (2 + 1) dimensions based on networks of Wilson lines. With the help of the q deformation, networks respect the (discretized) SU(3) gauge symmetry as a quantum group, i.e., SU(3) k, and may enable implementations of SU(3) Yang-Mills theory in quantum and classical algorithms by referring to those of the stringnet model. As a demonstration, we perform a mean-field computation of the groundstate of SU(3) k Yang-Mills theory, which is in good agreement with the conventional Monte Carlo simulation by taking sufficiently large k. The variational ansatz of the mean-field computation can be represented by the tensor networks called infinite projected entangled pair states. The success of the mean-field computation indicates that the essential features of Yang-Mills theory are well described by tensor networks, so that they may be useful in numerical simulations of Yang-Mills theory.

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Papers, etc., Registered in KOARA 【 Display / hide 】

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

  • ゲージ理論のための量子計算手法の開発と非平衡現象への応用

    2024.04
    -
    2027.03

    基盤研究(B), Principal investigator

  • 自己駆動する集団におけるカイラル輸送現象の研究

    2021.04
    -
    2024.03

    MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Principal investigator

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Courses Taught 【 Display / hide 】

  • PHYSICS 2

    2024

  • PHYSICS 1

    2024

  • LABORATORY OF PHYSICS

    2024

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