古賀 昌久Akihisa Koga
☰

研究業績

Publications

原著論文

    Preprint

    Stealthy hyperuniform disorder: A new route to controlling electric states and magnetic phase transition in correlated systems A. Koga and T. Sugimoto, arXiv:2604.19041.
    Holographic Aspects of Dynamical Mean-Field Theory K. Okunishi and A. Koga, arxiv:2509.19704.

    2026

    Impact of Stealthy Hyperuniform Magnetic Impurity Configurations on Bulk Magnetism in a Two-dimensional Heisenberg Model K. Asakura, K. Yamamoto, and A. Koga, Phys. Rev. B, 114, 024403 1-9 (2026).
    Generalized Nagaoka ferromagnetism accompanied by flavor-selective Mott states in an SU(N) Fermi-Hubbard model J. Fujii, K. Yamamoto, and A. Koga, Phys. Rev. B, 113, 115132 1-11 (2026).
    Elliptical-rod geometries enhance photonic band gaps in disordered stealthy hyperuniform photonic crystals K. Asakura, K. Yamamoto, and A. Koga, J. Phys. Soc. Jpn., 95, 024711 1-6 (2026).

    2025

    Spin-Depairing-Induced Exceptional Fermionic Superfluidity S. Takemori, K. Yamamoto, and A. Koga, Phys. Rev. Lett., 135, 266002 1-11 (2025).
    Itinerant ferromagnetism in an SU(3) Fermi-Hubbard model at finite temperature: A DMFT study J. Fujii, K . Yamamoto, and A. Koga, Phys. Rev. B, 112, 115136 1-11 (2025).
    Measurement-induced phase transitions for free fermions in a quasiperiodic potential T. Matsubara, K. Yamamoto and A. Koga, Phys. Rev. B, 112, 054309 1-13 (2025).
    Quasiperiodically modulated honeycomb lattices and their magnetic properties A. Koga and T. Matsubara, Phys. Rev. B, 111, 214422 1-14 (2025).
    Triangular and dice quasicrystals modulated by generic 1D aperiodic sequences T. Matsubara, A. Koga and T. Dotera, Phys. Rev. B, 111, 104104 1-12 (2025).
    Critical behavior of the Ising model on square-triangle tilings A. Koga and S. Sakai, Phys. Rev. B, 111, 014429 1-8 (2025).

    2024

    Phase diagram of non-Hermitian BCS superfluids in a dissipative asymmetric Hubbard model S. Takemori, K. Yamamoto, and A. Koga, Phys. Rev. B, 110, 184518 1-10 (2024).
    Hyperuniform properties of the square-triangle tilings A. Koga, S. Sakai, Y. Matsushita, and T. Ishimasa, Phys. Rev. B, 110, 094208 1-13 (2024).
    Hexagonal and trigonal quasiperiodic tilings S. Coates, A. Koga, T. Matsubara, R. Tamura, H. R. Sharma, R. McGrath, and R. Lifshitz, Isr. J. Chem, , e202300100 1-18 (2024).
    Aperiodic approximants bridging quasicrystals and modulated structures T. Matsubara, A. Koga, A. Takano, Y. Matsushita, and T. Dotera, Nat. Comm., 15, 5742 1-8 (2024).
    Hyperuniformity in two-dimensional periodic and quasiperiodic point patterns A. Koga and S. Sakai, Phys. Rev. E, 109, 044103 1-10 (2024).
    Theory of Non-Hermitian Fermionic Superfluidity on a Honeycomb Lattice: Interplay between Exceptional Manifolds and Van Hove Singularity S. Takemori, K. Yamamoto, and A. Koga, Phys. Rev. B, 109, L060501 1-7 (2024).
    Ferromagnetically ordered states in the Hubbard model on the H00 hexagonal golden-mean tiling T. Matsubara, A. Koga, and S. Coates, Phys. Rev. B, 109, 014413 1-11 (2024).

    2023

    Efficient Control of High Harmonic Generation in Carbon Nanotubes using the Aharonov-Bohm Effect Y. Murakami, K. Nagai, and A. Koga, Phys. Rev. B, 108, L241202 1-6 (2023).
    Energy flow during relaxation in an electron-phonon system with multiple modes: A nonequilibrium Green's function study K. Inayoshi, A. Koga, and Y. Murakami, J. Phys. Soc. Jpn., 92, 124001 1-17 (2023).
    Quantum algorithm for the microcanonical Thermal Pure Quantum method K. Mizukami and A. Koga, Phys. Rev. A, 108, 012404 1-10 (2023).
    Majorana Gap Formation in the Anisotropic Kitaev Model with Ordered Flux Configuration A. Hashimoto, Y. Murakami, and A. Koga, Phys. Rev. B, 107, 174428 1-8 (2023).

    2022

    Optical response of the tightbinding model on the Fibonacci chain H. Iijima, Y. Murakami, and A. Koga, J. Phys. Soc. Jpn., 91, 124702 1-5 (2022).
    Anomalous temperature dependence of high-harmonic generation in Mott insulators Y. Murakami, K. Uchida, A. Koga, K. Tanaka, and P. Werner, Phys. Rev. Lett., 129, 157401 1-6 (2022).
    Scattering phenomena for spin transport in Kitaev spin liquid J. Nasu, Y. Murakami, and A. Koga, Phys. Rev. B, 106, 024411 1-15 (2022).
    Thermally enhanced Majorana-mediated spin transport in the Kitaev model H. Taguchi, Y. Murakami and A. Koga, Phys. Rev. B, 105, 125137 1-6 (2022).
    Ferrimagnetically ordered states in the Hubbard model on the hexagonal golden-mean tiling A. Koga and S. Coates, Phys. Rev. B, 105, 104410 1-9 (2022).
    Photoinduced dynamics of a quasicrystalline excitonic insulator K. Inayoshi, Y. Murakami, and A. Koga, Phys. Rev. B, 105, 104307 1-13 (2022).

    2021

    Role of Majorana fermions in spin transport of anisotropic Kitaev model H. Taguchi, Y. Murakami, A. Koga and J. Nasu, Phys. Rev. B, 104, 125139 1-8 (2021).
    Unconventional Pairing from Local Orbital Fluctuations in Strongly Correlated A3C60 C. Yue, S. Hoshino, A. Koga, and P. Werner, Phys. Rev. B, 104, 075107 1-8 (2021).
    Majorana correlations in the Kitaev model with ordered-flux structures A. Koga, Y. Murakami, and J. Nasu, Phys. Rev. B, 103, 214421 1-9 (2021).
    Antiferromagnetically ordered state in the half-filled Hubbard model on the Socolar dodecagonal tiling A. Koga, Mater. Trans., 62, 360-366 (2021).
    Effect of Electron-Electron Interactions on Metallic State in Quasicrystals S. Sakai and A. Koga, Mater. Trans., 62, 380-385 (2021).
    High-harmonic generation in one-dimensional Mott insulator Y. Murakami, S. Takayoshi, A. Koga, and P. Werner, Phys. Rev. B, 103, 035110 1-14 (2021).

    2020

    Superlattice structure in the antiferromagnetically ordered state in the Hubbard model on the Ammann-Beenker tiling A. Koga, Phys. Rev. B, 102, 115125 1-10 (2020).
    Majorana-mediated spin transport in Kitaev quantum spin liquids T. Minakawa, Y. Murakami, A. Koga, and J. Nasu, Phys. Rev. Lett., 125, 047204 1-7 (2020).
    Collective Modes in Excitonic Insulators: Effects of Electron-Phonon Coupling and Signatures in Optical Response Y. Murakami, D. Golez, T. Kaneko, A. Koga, A. J. Millis, and P. Werner, Phys. Rev. B, 101, 195118 1-17 (2020).
    Excitonic condensation reflecting electronic states in two-band Penrose-Hubbard model K. Inayoshi, Y. Murakami, and A. Koga, J. Phys. Soc. Jpn., 89, 064002 1-8 (2020).
    Spin transport in the Quantum Spin Liquid State in the S=1 Kitaev model: role of the fractionalized quasiparticles A. Koga, T. Minakawa, Y. Murakami, and J. Nasu, J. Phys. Soc. Jpn., 89, 033701 1-4 (2020).

    2019

    Residual entropy and spin fractionalizations in the mixed-spin Kitaev model A. Koga and J. Nasu, Phys. Rev. B, 100, 100404 1-5 (2019).
    Ferromagnetic Instability for single-band Hubbard model in the strong-coupling regime Y. Kamogawa, J. Nasu, and A. Koga, Phys. Rev. B, 99, 235107 1-6 (2019).
    Low temperature properties in the Bilayer Kitaev model H. Tomishige, J. Nasu, and A. Koga, Phys. Rev. B, 99, 174424 1-5 (2019).
    Quantum and classical behavior of spin-S Kitaev models in an anisotropic limit T. Minakawa, J. Nasu, and A. Koga, Phys. Rev. B, 99, 104408 1-8 (2019).
    Staggered ordered phases in the three-orbital Hubbard model K. Ishigaki, J. Nasu, A. Koga, S. Hoshino, and P. Werner, Phys. Rev. B, 99, 085131 1-11 (2019).
    Symmetry breaking states in the half-filled two-orbital Hubbard model with crystalline electric field K. Ishigaki, J. Nasu, and A. Koga, J. Phys. Soc. Jpn., 88, 024702 1-5 (2019).

    2018

    Spontaneously orbital-selective superconductivity in a three-orbital Hubbard model K. Ishigaki, J. Nasu, A. Koga, S. Hoshino, and P. Werner, Phys. Rev. B, 98, 235120 1-7 (2018).
    Incipient and well-developed entropy plateaus in spin-S Kitaev models J. Oitmaa, A. Koga, and R. R. P. Singh, Phys. Rev. B, 98, 214404 1-6 (2018).
    Ground-state and thermodynamic properties of an S=1 Kitaev model A. Koga, H. Tomishige, and J. Nasu, J. Phys. Soc. Jpn., 87, 063703 1-4 (2018).
    Role of spin-orbit coupling in the Kugel-Khomskii model on the honeycomb lattice A. Koga, S. Nakauchi, and J. Nasu, Phys. Rev. B, 97, 094427 1-5 (2018).
    Charge Kondo Effect and Superconductivity in the Falikov-Kimball model with the Pair Hopping R. Shinzaki, J. Nasu, and A. Koga, Phys. Rev. B, 97, 125130 1-6 (2018).
    Interlayer Coupling Effect on a Bilayer Kitaev Model H. Tomishige, J. Nasu, and A. Koga, Phys. Rev. B, 97, 094403 1-9 (2018).

    2017

    Antiferromagnetic order in the Hubbard Model on the Penrose Lattice A. Koga and H. Tsunetsugu, Phys. Rev. B, 96, 214402 1-17 (2017).
    Spontaneously symmetry breaking states in the attractive SU(N) Hubbard model A. Koga and H. Yanatori, J. Phys. Soc. Jpn., 86, 034702 1-7 (2017).
    Superconductivity on a Quasiperiodic Lattice: Extended-to-Localized Crossover of Cooper Pairs S. Sakai, N. Takemori, A. Koga, and R. Arita, Phys. Rev. B, 95, 024509 1-5 (2017).

    2016

    Magnetic Response and Valence Fluctuations in the Extended Anderson Lattice Model with Quasiperiodicity R. Shinzaki, J. Nasu, and A. Koga, J. Phys. Soc. Jpn., 85, 114706 1-6 (2016).
    Finite Temperature Phase Transitions in the SU(N) Hubbard model H. Yanatori and A. Koga, Phys. Rev. B, 94, 041110 1-5 (2016).
    Phase transitions in the Hubbard model for the bismuth nickelate S. Kojima, J. Nasu, and A. Koga, Phys. Rev. B, 94, 045103 1-6 (2016).
    Finite Temperature Properties of Three-Component Fermion Systems in Optical Lattice H. Yanatori and A. Koga, J. Phys. Soc. Jpn., 85, 014002 1-5 (2016).

    2015

    Transport properties for a quantum dot coupled to normal leads with pseudogap B. Hara, A. Koga, and T. Aono, Phys. Rev. B, 92, 081103 1-5 (2015).
    Valence Fluctuations and Electric Reconstruction in the Extended Anderson Model on the Two-Dimensional Penrose Lattice S. Takemura, N. Takemori, and A. Koga, Phys. Rev. B, 91, 165114 1-6 (2015).
    Superconductivity in the two-band Hubbard model A. Koga and P. Werner, Phys. Rev. B, 91, 085108 1-7 (2015).
    Local Electron Correlations in a Two-dimensional Hubbard Model on the Penrose Lattice N. Takemori and A. Koga, J. Phys. Soc. Jpn., 84, 023701 1-5 (2015).

    2014

    Stability of the Superfluid State in Three-Component Fermionic Optical Lattice Systems Y. Okanami, N. Takemori and A. Koga, Phys. Rev. A, 89, 053622 1-8 (2014).
    Supersolid states in a hard-core Bose-Hubbard model on a layered triangular lattice R. Suzuki and A. Koga, J. Phys. Soc. Jpn., 83, 064003 1-6 (2014).

    2013

    Quantum Monte Carlo study of nonequilibrium transport through a quantum dot coupled to normal and superconducting leads A. Koga, Phys. Rev. B, 87, 115409 1-7 (2013).
    Mott transitions in the Hubbard model with spatially-modulated interactions A. Koga, T. Saitou, and A. Yamamoto, J. Phys. Soc. Jpn., 82, 024401 1-8 (2013).

    2012

    Stability of FFLO states in optical lattices with bilayer structure Y. Okawauchi and A. Koga, J. Phys. Soc. Jpn., 81, 074001 1-5 (2012).
    Low temperature properties of the fermionic mixtures with mass imbalance in optical lattice N. Takemori and A. Koga, J. Phys. Soc. Jpn., 81, 063002 1-4 (2012).
    A study on correlation effects in two dimensional topological insulators Y. Tada, R. Peters, M. Oshikawa, A. Koga, N. Kawakami, and S. Fujimoto, Phys. Rev. B, 85, 165138 1-18 (2012).

    2011

    Low temperature properties of the infinite-dimensional attractive Hubbard model A. Koga and P. Werner, Phys. Rev. A, 84, 023638 1-7 (2011).

    2010

    Superfluid state in the periodic Anderson model with attractive interactions A. Koga and P. Werner, J. Phys. Soc. Jpn., 79, 114401 1-7 (2010).
    Superfluid properties of ultracold fermionic atoms in two-dimensional optical lattices Y. Fujihara, A. Koga and N. Kawakami, Phys. Rev. A, 81, 063627 1-7 (2010).
    Polarized Superfluidity in the Imbalanced Attractive Hubbard Model A. Koga and P. Werner, J. Phys. Soc. Jpn., 79, 064401 1-6 (2010).

    2009

    Ferromagnetism of cold fermions loaded into a decorated square lattice K. Noda, A. Koga, N. Kawakami, and Th. Pruschke, Phys. Rev. A, 80, 063622 1-7 (2009).
    Quantum Phase Transitions in the Hubbard Model on a Triangular Lattice T. Yoshioka, A. Koga, and N. Kawakami, Phys. Rev. Lett., 103, 036401 1-4 (2009).
    Supersolid state in fermionic optical lattice systems A. Koga, T. Higashiyama, K. Inaba, S. Suga and N. Kawakami, Phys. Rev. A, 79, 013607 1-6 (2009).
    Spatially-modulated Superfluid States in Fermionic Optical Ladder Systems with Repulsive Interactions Y. Fujihara, A. Koga, and N. Kawakami, Phys. Rev. A, 79, 013610 1-7 (2009).

    2008

    Frustration effects in an anisotropic checkerboard lattice Hubbard model T. Yoshioka, A. Koga, and N. Kawakami, Phys. Rev. B, 78, 165113 1-6 (2008).
    Mott Transition in the Hubbard Model on Checkerboard Lattice T. Yoshioka, A. Koga, and N. Kawakami, J. Phys. Soc. Jpn., 77, 104702 1-7 (2008).
    Supersolid state of ultracold fermions in an optical lattice A. Koga, T. Higashiyama, K. Inaba, S. Suga, and N. Kawakami, J. Phys. Soc. Jpn., 77, 073602 1-4 (2008).
    Magnetic properties of the extended periodic Anderson model A. Koga, N. Kawakami, R. Peters, and Th. Pruschke, J. Phys. Soc. Jpn., 77, 033704 1-4 (2008).
    Quantum phase transitions in the extended periodic Anderson model A. Koga, N. Kawakami, R. Peters, and Th. Pruschke, Phys. Rev. B, 77, 045120 1-7 (2008).

    2007

    Metal-insulator transition in the two-orbital Hubbard model at fractional band fillings: Self-energy functional approach K. Inaba and A. Koga, J. Phys. Soc. Jpn., 76, 094712 1-7 (2007).
    Variational Monte Carlo Analysis of Hubbard Model with Confining Potential: One-Dimensional Fermionic Optical Lattice Systems Y. Fujihara, A. Koga, N. Kawakami, J. Phys. Soc. Jpn., 76, 034716 1-8 (2007).

    2006

    Phase Diagrams of the Two-Orbital Hubbard Model with Different Bandwidths K. Inaba and A. Koga, Phys. Rev. B, 73, 155106 1-8 (2006).

    2005

    Phase diagram of orbital-selective Mott transitions at finite temperatures K. Inaba, A. Koga, S. Suga, and N. Kawakami, J. Phys. Soc. Jpn., 74, 2393-2396 (2005).
    Finite-temperature Mott transitions in multi-orbital Hubbard model K. Inaba, A. Koga, S. Suga, and N. Kawakami, Phys. Rev. B, 72, 085112 1-7 (2005).
    Spin, charge, and orbital fluctuations in a multiorbital Mott insulator A. Koga, N. Kawakami, T.M. Rice and M. Sigrist, Phys. Rev. B, 72, 045128 1-8 (2005).

    2004

    Field-induced Phase transitions in the Kondo Insulator T. Ohashi, A. Koga, S. Suga, and N. Kawakami, Phys. Rev. B, 70, 245104 1-6 (2004).
    Periodic Anderson Model with Degenerate Orbitals: Linearized Dynamical Mean Field Theory Approach R. Sato, T. Ohashi, A. Koga, and N. Kawakami, J. Phys. Soc. Jpn., 73, 1864-1869 (2004).
    Frustrated Ising model on the garnet lattice T. Yoshioka, A. Koga and N. Kawakami, J. Phys. Soc. Jpn., 73, 1805-1811 (2004).
    Orbital-selective Mott transitions in the degenerate Hubbard model A. Koga, N. Kawakami, T.M. Rice and M. Sigrist, Phys. Rev. Lett., 92, 216402 1-4 (2004).
    Hole Dynamics in the Orthogonal-Dimer Spin System Y. Saito, A. Koga and N. Kawakami, J. Phys. Soc. Jpn., 73, 687-693 (2004).
    Superconductivity without inversion symmetry: $\bf MnSi$ versus $\rm\bf CePt_3Si$ P. Frigeri, D. F. Agterberg, A. Koga and M. Sigrist, Phys. Rev. Lett., 92, 097001 1-4 (2004).

    2003

    Effects of Degenerate Orbitals on the Hubbard model A. Koga, T. Ohashi, Y. Imai, S. Suga and N. Kawakami, J. Phys. Soc. Jpn., 72, 1306-1307 (2003).
    Hole-Doping Effects on a Two-Dimensional Kondo Insulator Y. Saito, A. Koga and N. Kawakami, J. Phys. Soc. Jpn., 72, 1208-1215 (2003).
    Quantum Phase Transitions of the S=1 Shastry-Sutherland Model A. Koga, N. Kawakami and M. Sigrist, J. Phys. Soc. Jpn., 72, 938-942 (2003).
    Hole-Doping Effects on a Frustrated Spin Ladder A. Kawaguchi, A. Koga, K. Okunishi and N. Kawakami, J. Phys. Soc. Jpn., 72, 405-410 (2003).

    2002

    Stability of a metallic state in the two-orbital Hubbard model A. Koga, Y. Imai and N. Kawakami, Phys. Rev. B, 66, 165107 1-6 (2002).
    Frustration-induced phase transitions in the spin-S orthogonal-dimer chain A. Koga and N. Kawakami, Phys. Rev. B, 65, 214415 1-5 (2002).
    Re-Entrant Quantum Phase Transitions in Antiferromagnetic Spin-1 Ladders S. Yamamoto, T. Sakai and A. Koga, J. Phys. Soc. Jpn., 71, 1250-1253 (2002).
    Magnetization process for a quasi-one-dimensional S=1 antiferromagnet A. Kawaguchi, A. Koga, K. Okunishi and N. Kawakami, Phys. Rev. B, 65, 214405 1-5 (2002).
    Quasi-one dimensional Haldane gap systems with single-ion anisotropy A. Koga, Phys. Lett. A, 296, 243-249 (2002).

    2001

    Competing Spin-Gap Phases in a Frustrated Quantum Spin System in Two Dimensions Y. Takushima, A. Koga and N. Kawakami, J. Phys. Soc. Jpn., 70, 1369-1374 (2001).
    Frustrated Heisenberg antiferromagnet on the pyrochlore lattice A. Koga and N. Kawakami, Phys. Rev. B, 63, 144432 1-5 (2001).

    2000

    Ground-State Phase Diagram for the Three-Dimensional Orthogonal-Dimer System A. Koga, J. Phys. Soc. Jpn., 69, 3509-3512 (2000).
    First-order quantum phase transition in the orthogonal-dimer spin chain A. Koga, K. Okunishi and N. Kawakami, Phys. Rev. B, 62, 5558-5563 (2000).
    Phase Diagram for Two-Dimensional Spin Systems with Ladder, Plaquette and Mixed-Spin Structures A. Koga and N. Kawakami, J. Phys. Soc. Jpn., 69, 1834-1836 (2000).
    Magnetic Double Structure for S=1 and 1/2 Mixed-Spin Systems Y. Takushima, A. Koga and N. Kawakami, Phys. Rev. B, 61, 15189-15195 (2000).
    Quantum phase transitions in the Shastry-Sutherland model for $\rm\bf SrCu_2(BO_3)_2$ A. Koga and N. Kawakami, Phys. Rev. Lett., 84, 4461-4464 (2000).
    Quantum phase transitions for the Haldane system in higher dimensions: A mixed-spin cluster expansion approach A. Koga and N. Kawakami, Phys. Rev. B, 61, 6133-6137 (2000).

    1999

    Quantum Phase Transitions in Two-Dimensional Spin Systems with Ladder, Plaquette and Mixed-Spin Structures A. Koga, S. Kumada and N. Kawakami, J. Phys. Soc. Jpn., 68, 2373-2379 (1999).
    Two-Dimensional Quantum Spin Systems with Ladder and Plaquette Structures A. Koga, S. Kumada and N. Kawakami, J. Phys. Soc. Jpn., 68, 642-649 (1999).

    1998

    Mixed-Spin Ladders and Plaquette Spin Chains A. Koga, S. Kumada, N. Kawakami and T. Fukui, J. Phys. Soc. Jpn., 67, 622-628 (1998).