Research

Exploring wonders of quantum mechanical world with theories and computations

We are interested in quantum many-body problems in fermionic systems, ranging from nuclear structure and reactions, physics of neutron stars, ultracold atomic gases, and superfluid phenomena.

Ongoing projects

Development of a stochastic mean-field theory for proper description of distributions of reaction outcomes

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References:

1. S. Ayik and K. Sekizawa, Kinetic energy dissipation and fluctuations in strongly-damped heavy-ion collisions within the stochastic mean-field approach, Phys. Rev. C 102, 064619 (2020) [arXiv:2009.11978]
2. K. Sekizawa and S. Ayik, Quantal diffusion approach for multinucleon transfer processes in the ^58,64Ni+²⁰⁸Pb reactions: Toward the production of unknown neutron-rich nuclei, Phys. Rev. C 102, 014620 (2020) [arXiv:2003.07786]

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Generation and decay dynamics of topological excitations in spin-(un)polarized unitary Fermi gases

In Fermionic systems, superfluidity is realized by the Cooper pairing mechanism where two Fermions with an opposite spin form a Bosonic pair. When the numbers of spin-up and spin-down particles are imbalanced, i.e. in a spin-polarized system, the Cooper pairing mechanism is frustrated. It is not at all obvious how the excess particles that cannot form pairs affect static and dynamic properties of the superfluid. Based on the time-dependent density functional theory (TDDFT), extended for spin-polarized, superfluid systems (which we call TDASLDA), we are exploring similarity and difference between Bosonic and Fermionic superfluid dynamics. In Refs. [1,2], we have studied decay cascades of topological excitations (domain wall, vortex ring, vortex line) as well as generation and decay of tangled vortices (quantum turbulence) in spin-(un)polarized unitary Fermi gases. The movie is from Ref. [1], showing an example of our simulations for rotating quantum turbulence.

References:

1. K. Hossain, K. Kobuszewski, M.M. Forbes, P. Magierski, K. Sekizawa, and G. Wlazłowski, Rotating Quantum Turbulence in the Unitary Fermi Gas, Phys. Rev. A 105, 013304 (2022) [arXiv:2010.07464]
2. G. Wlazłowski, K. Sekizawa, M. Marchwiany, and P. Magierski, Suppressed Solitonic Cascade in Spin-Imbalanced Superfluid Fermi Gas, Phys. Rev. Lett. 120, 253002 (2018) [arXiv:1711.05803]

Graduation Research

FY2022

1. Kentaro Kaba, Effects of the Landau Quantization of Electrons Under a Strong Magnetic Field on Compositions of the Outer Crust of Neutron Stars: Possible Emergence of Superheavy Nuclei.
2. Nobuaki Tani, On Numerical Stability of 1-Dimensional Skyrme Hartree-Fock Method.

FY2021

1. Tomoyuki Yoshikawa, Analysis of Single-Particle Wave Functions and Pairing Correlations in Ca Isotopes Using a Spherical Woods-Saxon Potential.
2. Kenta Yoshimura, Examining Entrainment Effects in the Inner Crust of Neutron Stars with Time-Dependent Self-Consistent Band Theory Calculations.

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Check out the current members!

Language: English / 日本語

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