論文

• Toranosuke Matsubara, Akihisa Koga, Atsushi Takano, Yushu Matsushita, Tomonari Dotera. Aperiodic approximants bridging quasicrystals and modulated structures, Nature Communications, July 2024.  公式リンク  
  
• Akihisa Koga, Shiro Sakai. Hyperuniformity in two-dimensional periodic and quasiperiodic point patterns, Physical Review E, Apr. 2024.  公式リンク  
  
• Soma Takemori, Kazuki Yamamoto, Akihisa Koga. Theory of non-Hermitian fermionic superfluidity on a honeycomb lattice: Interplay between exceptional manifolds and Van Hove singularity, Physical Review B, American Physical Society, Vol. 109, No. 6, pp. L060501, Feb. 2024.  公式リンク  
  
• Yuta Murakami, Kohei Nagai, Akihisa Koga. Efficient control of high harmonic terahertz generation in carbon nanotubes using the Aharonov-Bohm effect, Physical Review B, Dec. 2023.  公式リンク  
  
• Ken Inayoshi, Akihisa Koga, Yuta Murakami. Energy Flow during Relaxation in an Electron–Phonon System with Multiple Modes: A Nonequilibrium Green’s Function Study, Journal of the Physical Society of Japan, Dec. 2023.  公式リンク  
  
• Kaito Mizukami, Akihisa Koga. Quantum algorithm for the microcanonical thermal pure quantum state method, Physical Review A, July 2023.  公式リンク  
  
• Akihiro Hashimoto, Yuta Murakami, Akihisa Koga. Majorana gap formation in the anisotropic Kitaev model with ordered flux configuration, Physical Review B, May 2023.  公式リンク  
  
• Hiroki Iijima, Yuta Murakami, Akihisa Koga. Optical Response of the Tightbinding Model on the Fibonacci Chain, Journal of the Physical Society of Japan, Dec. 2022.  公式リンク  
  
• Yuta Murakami, Kento Uchida, Akihisa Koga, Koichiro Tanaka, Philipp Werner. Anomalous Temperature Dependence of High-Harmonic Generation in Mott Insulators, Physical Review Letters, Oct. 2022.  公式リンク  
  
• Joji Nasu, Yuta Murakami, Akihisa Koga. Scattering phenomena for spin transport in a Kitaev spin liquid, Physical Review B, July 2022.  公式リンク  
  
• Ken Inayoshi, Yuta Murakami, Akihisa Koga. Photoinduced dynamics of a quasicrystalline excitonic insulator, Physical Review B, Vol. 105, No. 10, Mar. 2022.  公式リンク  
  
• Akihisa Koga, Sam Coates. Ferrimagnetically ordered states in the Hubbard model on the hexagonal golden-mean tiling, Physical Review B, Mar. 2022.  公式リンク  
  
• Hirokazu Taguchi, Yuta Murakami, Akihisa Koga. Thermally enhanced Majorana-mediated spin transport in the Kitaev model, Physical Review B, Vol. 105, No. 12, Mar. 2022.  公式リンク  
  
• Hirokazu Taguchi, Yuta Murakami, Akihisa Koga, Joji Nasu. Role of Majorana fermions in spin transport of anisotropic Kitaev model, Physical Review B, Sept. 2021.  公式リンク  
  
• Changming Yue, Shintaro Hoshino, Akihisa Koga, Philipp Werner. Unconventional pairing from local orbital fluctuations in strongly correlated A3C60, Physical Review B, Aug. 2021.  公式リンク  
  
• Akihisa Koga, Yuta Murakami, Joji Nasu. Majorana correlations in the Kitaev model with ordered-flux structures, Physical Review B, June 2021.  公式リンク  
  
• Akihisa Koga. Antiferromagnetically Ordered State in the Half-Filled Hubbard Model on the Socolar Dodecagonal Tiling, MATERIALS TRANSACTIONS, Vol. 62, Page 360, Mar. 2021.  公式リンク  
  
• Shiro Sakai, Akihisa Koga. Effect of Electron-Electron Interactions on Metallic State in Quasicrystals, MATERIALS TRANSACTIONS, Vol. 62, Page 380, Mar. 2021.
• Akihisa Koga, Yuusuke Kamogawa, Joji Nasu. Ferromagnetically ordered metal in the single-band hubbard model, AIP Conference Proceedings, Vol. 2319, p. 130001, Feb. 2021.
• Yuta Murakami, Shintaro Takayoshi, Akihisa Koga, Philipp Werner. High-harmonic generation in one-dimensional Mott insulators, Physical Review B, Jan. 2021.  公式リンク  
  
• Akihisa Koga. Superlattice structure in the antiferromagnetically ordered state in the Hubbard model on the Ammann-Beenker tiling, Physical Review B, Sept. 2020.  公式リンク  
  
• Tetsuya Minakawa, Yuta Murakami, Akihisa Koga, Joji Nasu. Majorana-Mediated Spin Transport in Kitaev Quantum Spin Liquids, Physical Review Letters, July 2020.  公式リンク  
  
• Ken Inayoshi, Yuta Murakami, Akihisa Koga. Excitonic Condensation Reflecting Electronic States in Two-Band Penrose–Hubbard Model, Journal of the Physical Society of Japan, June 2020.  公式リンク  
  
• Akihisa Koga, Tetsuya Minakawa, Yuta Murakami, Joji Nasu. Spin Transport in the Quantum Spin Liquid State in the S = 1 Kitaev Model: Role of the Fractionalized Quasiparticles, Journal of the Physical Society of Japan, Mar. 2020.  公式リンク  
  
• Yojiro Taguchi, Joji Nasu, Akihisa Koga, Takuya Yoshioka, Hiroki Tsuchiura. Magnetic Properties in the Metallic Magnets with Large Anisotropy, Journal of Low Temperature Physics, Vol. 196, No. 1-2, pp. 321-326, July 2019.  公式リンク  
  
• Akihisa Koga, Hiroyuki Tomishige, Joji Nasu. Ground-State Properties for Bilayer Kitaev Model: Dimer Expansion Study, Journal of Superconductivity and Novel Magnetism, Vol. 32, No. 6, pp. 1827-1830, June 2019.  公式リンク  
  
• Akihisa Koga, Hiroyuki Tomishige, Joji Nasu. Ground-state and Thermodynamic Properties of an S = 1 Kitaev Model, Journal of the Physical Society of Japan, Vol. 87, No. 6, pp. 063703, June 2018.  公式リンク  
  
• Tomishige, Hiroyuki, Nasu, Joji, Koga, Akihisa, Akihisa Koga. Interlayer coupling effect on a bilayer Kitaev model, Physical Review B, Vol. 97, No. 9, 2018.  公式リンク  
  
• Koga, Akihisa, Nakauchi, Shiryu, Nasu, Joji, Akihisa Koga. Role of spin-orbit coupling in the Kugel-Khomskii model on the honeycomb lattice, Physical Review B, Vol. 97, No. 9, 2018.  公式リンク  
  
• Koga, Akihisa, Nakauchi, Shiryu, Nasu, Joji, Akihisa Koga. Ground-state phase diagram in the Kugel-Khomskii model with finite spin-orbit interactions, Physica B-Condensed Matter, Vol. 536, pp. 369-371, 2018.  公式リンク  
  
• Shinzaki, Ryu, Nasu, Joji, Koga, Akihisa, Akihisa Koga. Charge Kondo effect and superconductivity in the Falikov-Kimball model with pair hopping, Physical Review B, Vol. 97, No. 12, 2018.  公式リンク  
  
• Ryu Shinzaki, Joji Nasu, Akihisa Koga. Cluster Size Effects on Electronic Reconstruction in Quasiperiodic System, Journal of Physics: Conference Series, Vol. 809, pp. 012022-1-4, Mar. 2017.  公式リンク  
  
• Koga, Akihisa, Tsunetsugu, Hirokazu, Akihisa Koga. Antiferromagnetic order in the Hubbard model on the Penrose lattice, Physical Review B, Vol. 96, No. 21, 2017.  公式リンク  
  
• Sakai, Shiro, Takemori, Nayuta, Koga, Akihisa, Arita, Ryotaro, Akihisa Koga. Superconductivity on a quasiperiodic lattice: Extended-to-localized crossover of Cooper pairs, Physical Review B, Vol. 95, No. 2, 2017.  公式リンク  
  
• Koga, Akihisa, Yanatori, Hiromasa, Akihisa Koga. Spontaneously Symmetry-Breaking States in the Attractive SU(N) Hubbard Model, Journal of the Physical Society of Japan, Vol. 86, No. 3, 2017.  公式リンク  
  
• Ryu Shinzaki, Joji Nasu, Akihisa Koga. Magnetic Response and Valence Fluctuations in the Extended Anderson Lattice Model with Quasiperiodicity, Journal of the Physical Society of Japan, The Physical Society of Japan, 85, 114706-1-6, Oct. 2016.  公式リンク  
  
• Shoya Kojima, Joji Nasu, Akihisa Koga. Phase transitions in the Hubbard model for the bismuth nickelate, Physical Review B, Vol. 94, No. 4, July 2016.  公式リンク  
  
• Ryu Shinzaki, Joji Nasu, Akihisa Koga. DMFT Study for Valence Fluctuations in the Extended Periodic Anderson Model, Journal of Physics: Conference Series, Vol. 683, pp. 012041, Feb. 2016.  公式リンク  公式リンク  
  
• Hiromasa Yanatori, Akihisa Koga. Finite-temperature phase transitions in the SU(N) Hubbard model, Physical Review B, Vol. 94, No. 4, 2016.  公式リンク  
  
• Hiromasa Yanatori, Akihisa Koga. Finite Temperature Properties of Three-Component Fermion Systems in Optical Lattice, Journal of the Physical Society of Japan, Vol. 85, No. 1, 2016.  公式リンク  
  
• Bunpei Hara, Akihisa Koga, Aono, Tomosuke. Transport properties for a quantum dot coupled to normal leads with a pseudogap, Physical Review B, Vol. 92, No. 8, 2015.  公式リンク  
  
• Akihisa Koga, Werner, Philipp. Superconductivity in the two-band Hubbard model, Physical Review B, Vol. 91, No. 8, 2015.  公式リンク  
  
• Nayuta Takemori, Akihisa Koga. Local Electron Correlations in a Two-Dimensional Hubbard Model on the Penrose Lattice, Journal of the Physical Society of Japan, Vol. 84, No. 2, 2015.  公式リンク  
  
• Shin-ichi Takemura, Nayuta Takemori, Akihisa Koga. Valence fluctuations and electric reconstruction in the extended Anderson model on the two-dimensional Penrose lattice, Physical Review B, Vol. 91, No. 16, 2015.  公式リンク  
  
• Yuki Okanami, Nayuta Takemori, Akihisa Koga. Stability of the superfluid state in three-component fermionic optical lattice systems, Physical Review a, Vol. 89, No. 5, 2014.
• Ryota Suzuki, Akihisa Koga. Supersolid States in a Hard-Core Bose-Hubbard Model on a Layered Triangular Lattice, Journal of the Physical Society of Japan, Vol. 83, No. 6, 2014.
• Takamitu Saitou, Akihisa Koga, Yamamoto, A.. Metal-Insulator Transition in Optical Lattice System with Site-Dependent Interactions, Journal of Superconductivity and Novel Magnetism, Vol. 26, No. 5, pp. 1771-1774, 2013.
• Akihisa Koga, Takamitu Saitou, Yamamoto, Atsushi. Mott Transitions in the Hubbard Model with Spatially Modulated Interactions, Journal of the Physical Society of Japan, Vol. 82, No. 2, 2013.
• Akihisa Koga. Quantum Monte Carlo study of nonequilibrium transport through a quantum dot coupled to normal and superconducting leads, Physical Review B, Vol. 87, No. 11, 2013.
• Okawauchi, Yasuharu, Akihisa Koga. Stability of FFLO States in Optical Lattices with Bilayer Structure, Journal of the Physical Society of Japan, Vol. 81, No. 7, 2012.
• Nayuta Takemori, Akihisa Koga. Low-Temperature Properties of the Fermionic Mixtures with Mass Imbalance in Optical Lattice, Journal of the Physical Society of Japan, Vol. 81, No. 6, 2012.
• Akihisa Koga, Werner, Philipp, Sebastian, SE, Sutherland, ML, Pugh, E, Grosche, FM, Keeling, J, Panagopoulos, C, Rowley, S, Saxena, SS. Dynamical properties of ultracold fermions with attractive interactions in an optical lattice, International Conference on Strongly Correlated Electron Systems (Sces 2011), Vol. 391, 2012.
• Tada, Y., Peters, R., Oshikawa, M., Akihisa Koga, Kawakami, N., Fujimoto, S.. Correlation effects in two-dimensional topological insulators, Physical Review B, Vol. 85, No. 16, 2012.
• Akihisa Koga, Werner, Philipp, Saito, S, Tanaka, H, Nakamura, T, Nakamura, M. Superfluid state in the periodic Anderson model with attractive interactions, International Symposium: Nanoscience and Quantum Physics 2011 (Nanophys'11), Vol. 302, 2011.
• Akihisa Koga, Werner, Philipp. Low-temperature properties of the infinite-dimensional attractive Hubbard model, Physical Review a, Vol. 84, No. 2, 2011.
• Akihisa Koga, Werner, Philipp. PSEUDOGAP BEHAVIOR IN THE INFINITE DIMENSIONAL ATTRACTIVE HUBBARD MODEL, Modern Physics Letters B, Vol. 25, No. 12-13, pp. 973-978, 2011.
• Akihisa Koga, Bauer, J., Werner, P., Pruschke, Th. Polarized superfluid state in a three-dimensional fermionic optical lattice, Physica E-Low-Dimensional Systems & Nanostructures, Vol. 43, No. 3, pp. 697-701, 2011.
• Akihisa Koga, Werner, Philipp, Ronning, F, Batista, C. Superfluid gap formation in a fermionic optical lattice with spin imbalanced populations, International Conference on Strongly Correlated Electron Systems (Sces 2010), Vol. 273, 2011.
• Yoshioka, Takuya, Akihisa Koga, Kawakami, Norio. Magnetic transition in the Hubbard model on the triangular lattice, Physica B-Condensed Matter, Vol. 405, No. 11, pp. S179-S181, 2010.
• Fujihara, Yusuke, Akihisa Koga, Kawakami, Norio. Superfluid properties of ultracold fermionic atoms in two-dimensional optical lattices, Physical Review a, Vol. 81, No. 6, 2010.
• Akihisa Koga, Werner, Philipp. Superfluid State in the Periodic Anderson Model with Attractive Interactions, Journal of the Physical Society of Japan, Vol. 79, No. 11, 2010.
• Akihisa Koga, Werner, Philipp. Polarized Superfluidity in the Imbalanced Attractive Hubbard Model, Journal of the Physical Society of Japan, Vol. 79, No. 6, 2010.
• Yoshioka, Takuya, Akihisa Koga, Kawakami, Norio. Mott transition in the Hubbard model on the triangular lattice, Physica Status Solidi B-Basic Solid State Physics, Vol. 247, No. 3, pp. 635-637, 2010.
• Noda, Kazuto, Akihisa Koga, Kawakami, Norio, Pruschke, Thomas. Magnetically Ordered State of Cold Fermions on a Decorated Square Lattice, Journal of Low Temperature Physics, Vol. 158, No. 1-2, pp. 79-84, 2010.
• Fujihara, Yusuke, Akihisa Koga, Kawakami, Norio. Analysis of superfluid state of ultracold fermions with attractive interactions in two-dimensional optical lattices, Physica C-Superconductivity and Its Applications, Vol. 470, pp. S991-S992, 2010.
• Takuya Yoshioka, Akihisa Koga, Norio Kawakami. Quantum Phase Transitions in the Hubbard Model on a Triangular Lattice, Physical Review Letters, Vol. 103, No. 3, p. 036401, July 2009.
• Akihisa Koga, Higashiyama, T., Inaba, K., Suga, S., Kawakami, N., Kes, P, Jochemsen, R. Supersolid state in a fermionic optical lattice system, 25th International Conference on Low Temperature Physics (Lt25), Part 3, Vol. 150, 2009.
• Miyashita, Satoshi, Yamashita, Yasufumi, Yonemitsu, Kenji, Akihisa Koga, Kawakami, Norio, Kes, P, Jochemsen, R. Mott insulating state in a quarter-filled two-orbital Hubbard chain with different bandwidths, 25th International Conference on Low Temperature Physics (Lt25), Part 4, Vol. 150, 2009.
• Koyama, Yohta, Akihisa Koga, Kawakami, Norio, Werner, Philipp. Magnetic properties of the two-band Hubbard model with different bandwidths, Physica B-Condensed Matter, Vol. 404, No. 19, pp. 3267-3270, 2009.
• Noda, Kazuto, Akihisa Koga, Kawakami, Norio, Pruschke, Thomas. Ferromagnetism of cold fermions loaded into a decorated square lattice, Physical Review a, Vol. 80, No. 6, 2009.
• Inaba, K., Akihisa Koga, Suga, S., Kawakami, N., Kes, P, Jochemsen, R. Zero-temperature Phase Diagram of Two Dimensional Hubbard Model, 25th International Conference on Low Temperature Physics (Lt25), Part 4, Vol. 150, 2009.
• Akihisa Koga, Higashiyama, Takuji, Inaba, Kensuke, Suga, Seiichiro, Kawakami, Norio. Supersolid state in fermionic optical lattice systems, Physical Review a, Vol. 79, No. 1, 2009.
• Fujihara, Yusuke, Akihisa Koga, Kawakami, Norio. Superfluidity and magnetism in two-dimensional fermionic optical lattice systems, Physica B-Condensed Matter, Vol. 404, No. 19, pp. 3324-3327, 2009.
• Fujihara, Yusuke, Akihisa Koga, Kawakami, Norio. Spatially modulated superfluid states in fermionic optical ladder systems with repulsive interactions, Physical Review a, Vol. 79, No. 1, 2009.
• Akihisa Koga, Kawakami, Norio, Peters, Robert, Pruschke, Thomas. Phase transitions in the extended periodic Anderson model, Physica B-Condensed Matter, Vol. 403, No. 5-9, pp. 1378-1380, 2008.
• Fujihara, Yusuke, Akihisa Koga, Kawakami, Norio. Variational Monte Carlo analysis of singlet-pairing state in a system with inhomogeneous potential, Journal of Physics and Chemistry of Solids, Vol. 69, No. 12, pp. 3388-3391, 2008.
• Yoshioka, Takuya, Akihisa Koga, Kawakami, Norio. Frustration effects in an anisotropic checkerboard lattice Hubbard model, Physical Review B, Vol. 78, No. 16, 2008.
• Yoshioka, Takuya, Akihisa Koga, Kawakami, Norio. Instability of plaquette valence-bond crystal phase in planar pyrochlore electron system, Physica B-Condensed Matter, Vol. 403, No. 5-9, pp. 1248-1250, 2008.
• Akihisa Koga, Kawakami, Norio, Peters, Robert, Pruschke, Thomas. Magnetic properties of the extended periodic Anderson model, Journal of the Physical Society of Japan, Vol. 77, No. 3, 2008.
• Yoshioka, Takuya, Akihisa Koga, Kawakami, Norio. Mott Transition in the Hubbard Model on Checkerboard Lattice, Journal of the Physical Society of Japan, Vol. 77, No. 10, 2008.
• Akihisa Koga, Higashiyama, Takuji, Inaba, Kensuke, Suga, Seiichiro, Kawakami, Norio. Supersolid state of ultracold fermions in optical lattice, Journal of the Physical Society of Japan, Vol. 77, No. 7, 2008.
• Akihisa Koga, Kawakami, Norio, Peters, Robert, Pruschke, Thomas. Quantum phase transitions in the extended periodic Anderson model, Physical Review B, Vol. 77, No. 4, 2008.
• Inaba, Kensuke, Akihisa Koga. Metal-insulator transition in the two-orbital hubbard model at fractional band fillings: Self-energy functional approach, Journal of the Physical Society of Japan, Vol. 76, No. 9, 2007.
• Akihisa Koga, Yoshioka, Takuya, KawakaMi, Norio, Yokoyama, Hisatoshi. Electron correlations in the Hubbard model on the planar pyrochlore lattice, Physica C-Superconductivity and Its Applications, Vol. 460, pp. 1070-1071, 2007.
• Kuratani, Syunsuke, Akihisa Koga, Kawakami, Norio. Mott transition of correlated electrons on the Kagome lattice, Journal of Physics-Condensed Matter, Vol. 19, No. 14, 2007.
• Koyama, Y., Akihisa Koga, Kawakami, N.. Quantum Monte Carlo study of impurity Anderson models with degenerate orbitals, Journal of Magnetism and Magnetic Materials, Vol. 310, No. 2, pp. 405-407, 2007.
• Akihisa Koga, Yoshioka, Takuya, Kawakami, Norio, Yokoyama, Hisatoshi. Quantum phase transitions in the Hubbard model on the planar pyrochlore lattice, Journal of Magnetism and Magnetic Materials, Vol. 310, No. 2, pp. 867-869, 2007.
• Sigrist, Manfred, Agterberg, D. F., Frigeri, P. A., Hayashi, N., Kaur, R. P., Akihisa Koga, Milat, I., Wakabayashi, K., Yanase, Y.. Superconductivity in non-centrosymmetric materials, Journal of Magnetism and Magnetic Materials, Vol. 310, No. 2, pp. 536-540, 2007.
• Yoshioka, T., Akihisa Koga, Kawakami, N.. Systematic analysis of the Hubbard model on the checkerboard lattice, Journal of Magnetism and Magnetic Materials, Vol. 310, No. 2, pp. 873-875, 2007.
• Inaba, K., Akihisa Koga, Suga, S., Kawakami, N.. Thermodynamic properties of the two-orbital Hubbard model, Journal of Magnetism and Magnetic Materials, Vol. 310, No. 2, pp. 876-878, 2007.
• Fujihara, Yusuke, Akihisa Koga, Kawakami, Norio. Variational Monte Carlo analysis of Hubbard model with confining potential: One-dimensional fermionic optical lattice systems, Journal of the Physical Society of Japan, Vol. 76, No. 3, 2007.
• Fujihara, Yusuke, Akihisa Koga, Kawakami, Norio. Variational Monte Carlo study of Hubbard model with harmonic confinement, Journal of Magnetism and Magnetic Materials, Vol. 310, No. 2, pp. 882-884, 2007.
• Inaba, K, Akihisa Koga. Phase diagrams of the two-orbital Hubbard model with different bandwidths, Physical Review B, Vol. 73, No. 15, 2006.
• Sigrist, M, Agterberg, DF, Frigeri, PA, Hayashi, N, Kaur, RP, Akihisa Koga, Milat, I, Wakabayashi, K, Batrouni, GG, Poilblanc, D. Unconventional superconductivity in non-centrosymmetric materials, Effective Models For Low-Dimensional Strongly Correlated Systems, Vol. 816, pp. 124-135, 2006.
• Yoshioka, T, Akihisa Koga, Kawakami, N. Analysis of checkerboard electron system by path-integral renormalization group method, Physica B-Condensed Matter, Vol. 378-80, pp. 294-296, 2006.
• Agterberg, DF, Frigeri, PA, Kaur, RP, Akihisa Koga, Sigrist, M. Magnetic fields and superconductivity without inversion symmetry in CePt3Si, Physica B-Condensed Matter, Vol. 378-80, pp. 351-354, 2006.
• Akihisa Koga, Inaba, K, Kawakami, N. Mott transitions in two-orbital Hubbard systems, Progress of Theoretical Physics Supplement, No. 160, pp. 253-273, 2005.
• Inaba, K, Akihisa Koga, Suga, SI, Kawakami, N. Phase diagram of orbital-selective Mott transitions at finite temperatures, Journal of the Physical Society of Japan, Vol. 74, No. 9, pp. 2393-2396, 2005.
• Frigeri, PA, Agterberg, DF, Akihisa Koga, Sigrist, M. Superconductivity without inversion symmetry in CePt3Si, Physica B-Condensed Matter, Vol. 359, pp. 371-373, 2005.
• Akihisa Koga, Kawakami, N, Rice, TM, Sigrist, M. Spin, charge, and orbital fluctuations in a multiorbital Mott insulator, Physical Review B, Vol. 72, No. 4, 2005.
• Ohashi, T, Akihisa Koga, Suga, SI, Kawakami, N. Field-induced phase transition in the periodic Anderson model, Physica B-Condensed Matter, Vol. 359, pp. 738-740, 2005.
• Inaba, K, Akihisa Koga, Suga, S, Kawakami, N. Finite-temperature Mott transitions in the multiorbital Hubbard model, Physical Review B, Vol. 72, No. 8, 2005.
• Akihisa Koga, Kawakami, N, Rice, TM, Sigrist, M. Mott transitions in the multi-orbital systems, Physica B-Condensed Matter, Vol. 359, pp. 1366-1368, 2005.
• Frigeri, PA, Agterberg, DF, Akihisa Koga, Sigrist, M. Superconductivity without inversion symmetry: MnSi versus CePt3Si, Physical Review Letters, Vol. 92, No. 9, 2004.
• Ohashi, T, Akihisa Koga, Suga, S, Kawakami, N. Field-induced phase transitions in a Kondo insulator, Physical Review B, Vol. 70, No. 24, 2004.
• Yoshioka, T, Akihisa Koga, Kawakami, N. Frustrated ising model on the garnet lattice, Journal of the Physical Society of Japan, Vol. 73, No. 7, pp. 1805-1811, 2004.
• Saito, Y, Akihisa Koga, Kawakami, N. Hole dynamics in the orthogonal-dimer spin system, Journal of the Physical Society of Japan, Vol. 73, No. 3, pp. 687-693, 2004.
• Akihisa Koga, Kawakami, N, Rice, TM, Sigrist, M. Orbital-selective Mott transitions in the degenerate Hubbard model, Physical Review Letters, Vol. 92, No. 21, 2004.
• Sato, R, Ohashi, T, Akihisa Koga, Kawakami, N. Periodic Anderson model with degenerate orbitals: Linearized dynamical mean field theory approach, Journal of the Physical Society of Japan, Vol. 73, No. 7, pp. 1864-1869, 2004.
• Frigeri, PA, Agterberg, DF, Akihisa Koga, Sigrist, M. Superconductivity without inversion symmetry: MnSi versus CePt3Si (vol 92, art no 097001, 2004), Physical Review Letters, Vol. 93, No. 9, 2004.
• Akihisa Koga, Kawakami, N. Quantum phase transitions in a frustrated orthogonal-dimer S=1 spin system, Physica B-Condensed Matter, Vol. 329, pp. 1267-1268, 2003.
• Akihisa Koga, Kawakami, N, Sigrist, M. Quantum phase transitions of the S=1 Shastry-Sutherland model, Journal of the Physical Society of Japan, Vol. 72, No. 4, pp. 938-942, 2003.
• Saito, Y, Akihisa Koga, Kawakami, N. Hole-doping effects on a two-dimensional Kondo insulator, Journal of the Physical Society of Japan, Vol. 72, No. 5, pp. 1208-1215, 2003.
• Kawaguchi, A, Akihisa Koga, Okunishi, K, Kawakami, N. Hole-doping effects on a frustrated spin ladder, Journal of the Physical Society of Japan, Vol. 72, No. 2, pp. 405-410, 2003.
• Akihisa Koga, Ohashi, T, Imai, Y, Suga, S, Kawakami, N. Effects of degenerate orbitals on the Hubbard model, Journal of the Physical Society of Japan, Vol. 72, No. 5, pp. 1306-1307, 2003.
• Akihisa Koga, Kawakami, N. Effects of degenerate orbitals on the Anderson lattice model, Journal of Physics-Condensed Matter, Vol. 15, No. 28, pp. S2215-S2218, 2003.
• Yamamoto, S, Sakai, T, Akihisa Koga. Re-entrant quantum phase transitions in antiferromagnetic spin-1 ladders, Journal of the Physical Society of Japan, Vol. 71, No. 5, pp. 1250-1253, 2002.  公式リンク  
  
• Akihisa Koga, Kawakami, N, Sigrist, M. Hole-doping effects on an S=1 ladder system, Physica B-Condensed Matter, Vol. 312, pp. 606-608, 2002.
• Akihisa Koga, Kawaguchi, A, Okunishi, K, Kawakami, N. First-order phase transitions in frustrated spin systems, Progress of Theoretical Physics Supplement, No. 145, pp. 52-57, 2002.
• Akihisa Koga, Kawakami, N. Frustration-induced phase transitions in the spin-S orthogonal-dimer chain, Physical Review B, Vol. 65, No. 21, 2002.
• Kawaguchi, A, Akihisa Koga, Okunishi, K, Kawakami, N. Hole-doping effects on orthogonal-dimer spin chain, Journal of Physics and Chemistry of Solids, Vol. 63, No. 6-8, pp. 1431-1434, 2002.
• Kawaguchi, A, Akihisa Koga, Kawakami, N, Okunishi, K. Magnetization curves of quasi-one-dimensional haldane systems, International Journal of Modern Physics B, Vol. 16, No. 20-22, pp. 3339-3342, 2002.
• Kawaguchi, A, Akihisa Koga, Okunishi, K, Kawakami, N. Magnetization process for a quasi-one-dimensional S=1 antiferromagnet, Physical Review B, Vol. 65, No. 21, 2002.
• Yamamoto, S, Sakai, T, Akihisa Koga. Quantum phase competition in antiferromagnetic spin-1 ladders, Progress of Theoretical Physics Supplement, No. 145, pp. 176-181, 2002.
• Akihisa Koga. Quasi-one-dimensional Haldane gap systems with single-ion anisotropy, Physics Letters a, Vol. 296, No. 4-5, pp. 243-249, 2002.
• Akihisa Koga, Imai, Y, Kawakami, N. Stability of a metallic state in the two-orbital Hubbard model, Physical Review B, Vol. 66, No. 16, 2002.
• Akihisa Koga, Kawakami, N. Frustrated Heisenberg antiferromagnet on the pyrochlore lattice, Physical Review B, Vol. 63, No. 14, 2001.
• Takushima, Y, Akihisa Koga, Kawakami, N. Competing spin-gap phases in a frustrated quantum spin system in two dimensions, Journal of the Physical Society of Japan, Vol. 70, No. 5, pp. 1369-1374, 2001.
• Akihisa Koga, Kawakami, N. Quantum phase transitions for the three-dimensional orthogonal-dimer spin system, Computer Physics Communications, Vol. 142, No. 1-3, pp. 172-175, 2001.
• Takushima, Y, Akihisa Koga, Kawakami, N. Magnetic double structure for S=1 and S=1/2 mixed-spin systems, Physical Review B, Vol. 61, No. 22, pp. 15189-15195, 2000.
• Akihisa Koga, Kawakami, N. Quantum phase transitions in the Shastry-Sutherland model for SrCu2(BO3)(2), Physical Review Letters, Vol. 84, No. 19, pp. 4461-4464, 2000.
• Akihisa Koga, Kawakami, N. Phase diagram for two-dimensional spin systems with ladder, plaquette and mixed-spin structures, Journal of the Physical Society of Japan, Vol. 69, No. 6, pp. 1834-1836, 2000.
• Akihisa Koga, Kawakami, N. Quantum phase transitions for mixed-spin systems, Journal of the Physical Society of Japan, Vol. 69, pp. 319-325, 2000.
• Akihisa Koga, Kawakami, N. Quantum phase transitions for the Haldane system in higher dimensions: A mixed-spin cluster expansion approach, Physical Review B, Vol. 61, No. 9, pp. 6133-6137, 2000.
• Akihisa Koga, Okunishi, K, Kawakami, N. First-order quantum phase transition in the orthogonal-dimer spin chain, Physical Review B, Vol. 62, No. 9, pp. 5558-5563, 2000.
• Akihisa Koga, Kumada, S, Kawakami, N. Quantum phase transitions in two-dimensional spin systems with ladder, plaquette and mixed-spin structures, Journal of the Physical Society of Japan, Vol. 68, No. 7, pp. 2373-2379, 1999.  公式リンク  
  
• Akihisa Koga, Kumada, S, Kawakami, N. Two-dimensional quantum spill systems with ladder and Plaquette structures, Journal of the Physical Society of Japan, Vol. 68, No. 2, pp. 642-649, 1999.  公式リンク  
  
• Akihisa Koga, Kumada, S, Kawakami, N, Fukui, T. Mixed-spin ladders and plaquette spin chains, Journal of the Physical Society of Japan, Vol. 67, No. 2, pp. 622-628, 1998.  公式リンク  
  

著書

• 古賀 昌久. 物理数学 I 複素関数・ベクトル解析, 物理数学 I 複素関数・ベクトル解析, 丸善出版, 2016.

国際会議発表 (査読なし・不明)

• Akihisa Koga. Finite Temperature Phase Transitions in the multicomponent Hubbard model, Exotic States of Matter with SU(N) symmetry "Realizing SU(N) symmetry in condensed matter", July 2016.
• Akihisa Koga. Finite Temperature Phase Transitions in the multicomponent Hubbard model, Memorial Symmposium for Prof. Pruschke, July 2016.
• Akihisa Koga. Local electron correlations in the quasiperiodic systems, Toyota RIKEN International Workshop 2015 "Strongly Correlated Electron Systems: Open Space between Heavy Fermions and Quasi-crystals", Nov. 2015.
• Akihisa Koga. Superconductivity in the degenerate Hubbard model, TMU International Symposium 2015 "New Quantum Phases Emerging from Novel Crystal Structure", Sept. 2015.
• B. Hara, A. Koga, T. Aono. Transport properties for a quantum dot coupled to normal leads with the pseudogap structure, ISSP-MPIPKS joint workshop "Dynamics of Strongly Correlated Systems", Mar. 2015.
• S. Takemura, N. Takemori, A. Koga. Valence fluctuations in the extended periodic Anderson model on the two-dimensional Penrose lattice, A workshop on recent developments in the Kondo problem, Jan. 2015.

国内会議発表 (査読なし・不明)

• 古賀昌久. 二次元準周期タイルとハイパーユニフォーミティ, 準周期電子状態とマルチフラクタリティ・ハイパーユニフォーミティ, Jan. 2023.
• 古賀昌久. Valence fluctuations in heavy fermion system on the Penrose lattice, J-Physics: 多極子伝導系の物理 "平成28年度領域全体会議", May 2016.
• 那須譲治, 新崎龍, 古賀昌久. スピン1/2 Falicov-Kimball模型における準周期性と価数揺らぎ, 日本物理学会, 第71回年次大会, Mar. 2016.
• 那須譲治, 新崎龍, 古賀昌久. 動的平均場近似によるスピン 1/2 Falicov-Kimball 模型における準周期性と価数揺らぎ, 第20回準結晶研究会, Dec. 2015.
• 古賀昌久, 常次 宏一. 二次元ペンローズハバード模型における磁気的性質, 準結晶研究会, Dec. 2015.
• 古賀昌久, 竹村信一, 竹森那由多. 強相関準結晶系における価数ゆらぎと近藤効果, J-Physics: 多極子伝導系の物理 "キックオフミーティング", Sept. 2015.

学位論文

• 低次元スピン系における量子相転移の理論的研究,  本文,  博士(工学),  大阪大学,  2001/03/23, 

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