9 papers
Kondo breakdown induced by non-Hermitian complex hybridization
Kazuki Yamamoto, Masaya Nakagawa, Norio Kawakami
Recently, a non-Hermitian Anderson impurity model with one-body loss has been studied in [Phys. Rev. B 111, 125157 (2025)}], and it has been demonstrated that the renormalization e…
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…
Dimensionality effect on exceptional fermionic superfluidity with spin-dependent asymmetric hopping
Soma Takemori, Kazuki Yamamoto, Akihisa Koga
Non-Hermitian (NH) quantum systems host exceptional points (EPs), where eigenstates and eigenvalues coalesce, leading to unconventional many-body phenomena absent in Hermitian syst…