13 papers
Holographic Aspects of Dynamical Mean-Field Theory
Kouichi Okunishi, Akihisa Koga
Dynamical mean-field theory (DMFT) is one of the most standard theoretical frameworks for addressing strongly correlated electron systems. In this study, we explore a holographic r…
Stealthy hyperuniform disorder: A new route to controlling electric states and magnetic phase transition in correlated systems
Akihisa Koga, Takanori Sugimoto
We investigate the effects of stealthy hyperuniform bond distributions on the electronic and magnetic properties of the Hubbard model on the honeycomb lattice. Hyperuniform structu…
Generalized Nagaoka ferromagnetism accompanied by flavor-selective Mott states in an SU() Fermi-Hubbard model
Juntaro Fujii, Kazuki Yamamoto, Akihisa Koga
We study the ferromagnetic instability in an SU() Fermi-Hubbard model on the hypercubic lattice. Combining dynamical mean-field theory with continuous-time quantum Monte Carlo s…
Impact of Stealthy Hyperuniform Magnetic Impurity Configurations on Bulk Magnetism in a Two-dimensional Heisenberg Model
K. Asakura, K. Yamamoto, A. Koga
We investigate an antiferromagnetic quantum Heisenberg model on a square lattice with high-spin magnetic impurities to clarify how random and stealthy hyperuniform impurity configu…
Spin-Depairing-Induced Exceptional Fermionic Superfluidity
Soma Takemori, Kazuki Yamamoto, Akihisa Koga
We investigate the non-Hermitian (NH) attractive Hubbard model with spin depairing, which is a spin-resolved asymmetric hopping that nonreciprocally operates spins in the opposite…
Elliptical-rod geometries enhance photonic band gaps in disordered stealthy hyperuniform photonic crystals
Kota Asakura, Kazuki Yamamoto, Akihisa Koga
We study two-dimensional photonic crystals composed of elliptical dielectric rods arranged according to stealthy hyperuniform point patterns. These patterns are characterized by th…