Unperturbed approach to strongly correlated superconductivity: inhomogenity and frequency dependence

• Project/Area Number: 25800193
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Koga Akihisa 東京工業大学, 理学院, 准教授 (90335373)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2016: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2015: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2014: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2013: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 強相関系 / 超流動 / 準結晶

Outline of Final Research Achievements

Unconventional superconductivity in inhomogeneous systems has attracted much interest in strongly correlated fermion systems. In our study, we have treated dynamical correlations and inhomogeneity by means of the unperturbative approach. We have studied the superconductivity and superfluid states in the cold atomic and quasiperiodic systems to clarify the role of the frequency dependence in the strongly correlated systems.

Research Products

• [Journal Article] Spontaneously symmetry breaking states in the attractive SU(N) Hubbard model (2017)
  • Author(s): A. Koga and H. Yanatori
  • Journal Title: Journal of the Physical Society of Japan Volume: 86 Issue: 3 Pages: 0347021-7
  • DOI: 10.7566/jpsj.86.034702
  • NAID: 40021129711
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Superconductivity on a Quasiperiodic Lattice: Extended-to-Localized Crossover of Cooper Pairs (2017)
  • Author(s): S. Sakai, N. Takemori, A. Koga, and R. Arita
  • Journal Title: Physical Review B Volume: 95 Issue: 2 Pages: 0245091-5
  • DOI: 10.1103/physrevb.95.024509
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Cluster Size Effects on Electronic Reconstruction in Quasiperiodic System (2017)
  • Author(s): R. Shinzaki, J. Nasu, and A. Koga
  • Journal Title: Journal of Physics: Conference Series Volume: 809 Pages: 0120221-4
  • DOI: 10.1088/1742-6596/809/1/012022
  • Peer Reviewed / Open Access
• [Journal Article] Magnetic Response and Valence Fluctuations in the Extended Anderson Lattice Model with Quasiperiodicity (2016)
  • Author(s): R. Shinzaki, J. Nasu, and A. Koga
  • Journal Title: Journal of the Physical Society of Japan Volume: 85 Issue: 11 Pages: 1147061-6
  • DOI: 10.7566/jpsj.85.114706
  • NAID: 210000134154
  • Peer Reviewed
• [Journal Article] Finite Temperature Phase Transitions in the SU(N) Hubbard model (2016)
  • Author(s): H. Yanatori and A. Koga
  • Journal Title: Physical Review B Volume: 94 Issue: 4 Pages: 0411101-5
  • DOI: 10.1103/physrevb.94.041110
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Phase transitions in the Hubbard model for the bismuth nickelate (2016)
  • Author(s): S. Kojima, J. Nasu, and A. Koga
  • Journal Title: Physical Review B Volume: 94 Issue: 4 Pages: 0451031-6
  • DOI: 10.1103/physrevb.94.045103
  • Peer Reviewed
• [Journal Article] Finite Temperature Properties of Three-Component Fermion Systems in Optical Lattice (2016)
  • Author(s): H. Yanatori and A. Koga
  • Journal Title: Journal of Physical Society of Japan Volume: 85 Issue: 1 Pages: 0140021-5
  • DOI: 10.7566/jpsj.85.014002
  • NAID: 40020699806
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Intersite electron correlations in a Hubbard model on inhomogeneous lattices (2016)
  • Author(s): N. Takemori, A. Koga, and H. Hafermann
  • Journal Title: Journal of Physics Conference Series Volume: 683 Pages: 0120401-6
  • DOI: 10.1088/1742-6596/683/1/012040
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] DMFT Study for Valence Fluctuations in the Extended Periodic Anderson Model (2016)
  • Author(s): R. Shinzaki, J. Nasu, and A. Koga
  • Journal Title: Journal of Physics Conference Series Volume: 683 Pages: 021041-021041
  • DOI: 10.1088/1742-6596/683/1/012041
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Valence Fluctuations and Electric Reconstruction in the Extended Anderson Model on the Two-Dimensional Penrose Lattice (2015)
  • Author(s): S. Takemura, N. Takemori, and A. Koga
  • Journal Title: Physical Review B Volume: 91 Issue: 16 Pages: 0851081-7
  • DOI: 10.1103/physrevb.91.165114
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Transport properties for a quantum dot coupled to normal leads with a pseudogap (2015)
  • Author(s): Bunpei Hara, Akihisa Koga, and Tomosuke Aono
  • Journal Title: Phys. Rev. B Volume: 92 Issue: 8 Pages: 0811031-5
  • DOI: 10.1103/physrevb.92.081103
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Local Electron Correlations in a Two-dimensional Hubbard Model on the Penrose Lattice (2015)
  • Author(s): N. Takemori, A. Koga
  • Journal Title: Journal of Physical Society of Japan Volume: 84 Issue: 2 Pages: 0237011-5
  • DOI: 10.7566/jpsj.84.023701
  • NAID: 40020360527
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Superconductivity in the two-band Hubbard model (2015)
  • Author(s): A. Koga and P. Werner
  • Journal Title: Physical Review B Volume: 91 Issue: 8 Pages: 0851081-7
  • DOI: 10.1103/physrevb.91.085108
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Stabilities of Superfluid and Density Wave States in Fermionic Mass Imbalanced Optical Lattices (2015)
  • Author(s): N. Takemori and A. Koga
  • Journal Title: JPS Conference Proceedings Volume: 4 Pages: 0110061-4
  • DOI: 10.7566/jpscp.4.011006
  • Peer Reviewed
• [Journal Article] DMFT study of the local correlation effects in quasi-periodic system (2015)
  • Author(s): N. Takemori and A. Koga
  • Journal Title: Journal of Physics: Conference Series Volume: 592 Pages: 0120381-6
  • DOI: 10.1088/1742-6596/592/1/012038
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Supersolid states in a hard-core Bose-Hubbard model on a layered triangular lattice (2014)
  • Author(s): R. Suzuki and A. Koga
  • Journal Title: Journal of Physical Society of Japan Volume: 83 Issue: 6 Pages: 0640031-6
  • DOI: 10.7566/jpsj.83.064003
  • NAID: 40020091515
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Stability of the Superfluid State in Three-Component Fermionic Optical Lattice Systems (2014)
  • Author(s): Y. Okanami, N. Takemori and A. Koga
  • Journal Title: Physical Review A Volume: 89 Issue: 5 Pages: 0536221-8
  • DOI: 10.1103/physreva.89.053622
  • NAID: 110009754592
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Diagrammatic Quantum Monte Carlo Study of Nonequilibrium Transport through a Quantum Dot coupled to Normal and Superconducting Leads (2014)
  • Author(s): A. Koga
  • Journal Title: JPS Conference Proceedings Volume: 3 Pages: 0120181-6
  • DOI: 10.7566/jpscp.4.011003
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Cluster mean-field approach with density matrix renormalization group: Application to the hard-core bosonic Hubbard model on a triangular lattice (2014)
  • Author(s): R. Suzuki and A. Koga
  • Journal Title: JPS Conference Proceedings Volume: 3 Pages: 0160051-6
  • DOI: 10.7566/jpscp.3.016005
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Valence Fluctuations in the Extended Periodic Anderson Model at Finite Temperatures (2014)
  • Author(s): Y. Kojima and A. Koga
  • Journal Title: JPS Conference Proceedings Volume: 1 Pages: 0121061-4
  • DOI: 10.7566/jpscp.1.012106
  • Peer Reviewed
• [Presentation] Nd-Fe-B系の磁性に対する伝導電子の効果 (2017)
  • Author(s): 田口陽二郎, 那須譲治, 古賀昌久, 吉岡匠哉, 土浦宏紀
  • Organizer: 日本物理学会第72回年次大会
  • Place of Presentation: 大阪大学
• [Presentation] ペアホッピング由来の電荷近藤効果に対する軌道内斥力の影響 (2017)
  • Author(s): 新崎龍, 那須譲治, 古賀昌久
  • Organizer: 日本物理学会第72回年次大会
  • Place of Presentation: 大阪大学
• [Presentation] 2軌道ハバード模型における励起子相と軌道秩序相の競合 (2017)
  • Author(s): 石垣耕祐, 那須譲治, 古賀昌久
  • Organizer: 日本物理学会第72回年次大会
  • Place of Presentation: 大阪大学
• [Presentation] ペンローズ格子上の超伝導の理論研究 (2017)
  • Author(s): 酒井志朗, 竹森那由多, 古賀昌久, 有田亮太郎
  • Organizer: 日本物理学会第72回年次大会
  • Place of Presentation: 大阪大学
• [Presentation] 準周期ハバード模型におけるサイト間電子相関効果 (2016)
  • Author(s): 竹森那由多, 古賀昌久, Hartmut Hafermann
  • Organizer: 日本物理学会第71回年次大会
  • Place of Presentation: 東北学院大
  • Year and Date: 2016-03-22
• [Presentation] スピン軌道相互作用の強いt2g電子系に対するクラスター平均場による解析 (2016)
  • Author(s): 中内子竜, 那須譲治, 古賀昌久
  • Organizer: 日本物理学会第71回年次大会
  • Place of Presentation: 東北学院大
  • Year and Date: 2016-03-21
• [Presentation] 2次元ペンローズ格子上の拡張周期アンダーソン模型における価数揺動現象 (2016)
  • Author(s): 新崎龍, 那須譲治, 古賀昌久
  • Organizer: 日本物理学会第71回年次大会
  • Place of Presentation: 東北学院大
  • Year and Date: 2016-03-21
• [Presentation] スピン1/2 Falicov-Kimball模型における準周期性と価数揺らぎ (2016)
  • Author(s): 那須譲治, 新崎龍, 古賀昌久
  • Organizer: 日本物理学会第71回年次大会
  • Place of Presentation: 東北学院大
  • Year and Date: 2016-03-21
• [Presentation] 光格子中の多成分フェルミ粒子系における秩序相の解析 (2016)
  • Author(s): 梁取大将, 古賀昌久
  • Organizer: 日本物理学会第71回年次大会
  • Place of Presentation: 東北学院大
  • Year and Date: 2016-03-20
• [Presentation] 動的平均場理論によるBiNiO3有効模型の解析 (2016)
  • Author(s): 小嶋祥也, 那須譲治, 古賀昌久
  • Organizer: 日本物理学会第71回年次大会
  • Place of Presentation: 東北学院大
  • Year and Date: 2016-03-19
• [Presentation] SU(N)ハバード模型における秩序相の解析 (2016)
  • Author(s): 古賀昌久, 梁取大将
  • Organizer: 日本物理学会2016年秋季大会
  • Place of Presentation: 金沢大学
• [Presentation] 動的平均場理論によるペアホッピング由来の電荷近藤効果の解析 (2016)
  • Author(s): 新崎龍, 那須譲治, 古賀昌久
  • Organizer: 日本物理学会2016年秋季大会
  • Place of Presentation: 金沢大学
• [Presentation] 動的平均場理論を用いた有限温度における価数転移の解析 (2015)
  • Author(s): 新崎龍, 那須譲治, 古賀昌久
  • Organizer: 日本物理学会2015年秋季大会
  • Place of Presentation: 関西大
  • Year and Date: 2015-09-18
• [Presentation] 非一様系におけるサイト間相関を扱う計算手法開発と準周期系への適用 (2015)
  • Author(s): 竹森那由多, 古賀昌久, Hartmut Hafermann
  • Organizer: 日本物理学会2015年秋季大会
  • Place of Presentation: 関西大
  • Year and Date: 2015-09-17
• [Presentation] 2次元ペンローズ格子におけるサイト間相関効果 (2015)
  • Author(s): 竹森那由多，古賀昌久，Hartmut Hafermann
  • Organizer: 日本物理学会第70回年次大会
  • Place of Presentation: 早稲田大学
  • Year and Date: 2015-03-24
• [Presentation] 2次元準周期系における拡張周期アンダーソン模型の解析II (2015)
  • Author(s): 竹村信一，竹森那由多，古賀昌久
  • Organizer: 日本物理学会第70回年次大会
  • Place of Presentation: 早稲田大学
  • Year and Date: 2015-03-24
• [Presentation] 二次元ペンローズハバード模型における磁気的性質 (2015)
  • Author(s): 古賀昌久，常次宏一
  • Organizer: 日本物理学会第70回年次大会
  • Place of Presentation: 早稲田大学
  • Year and Date: 2015-03-24
• [Presentation] 擬ギャップ構造を持つリードに繋がれた量子ドットの輸送特性 (2015)
  • Author(s): 原文平，古賀昌久
  • Organizer: 日本物理学会第70回年次大会
  • Place of Presentation: 早稲田大学
  • Year and Date: 2015-03-22
• [Presentation] 3成分フェルミ粒子系における秩序相の解析 (2015)
  • Author(s): 梁取大将，古賀昌久
  • Organizer: 日本物理学会第70回年次大会
  • Place of Presentation: 早稲田大学
  • Year and Date: 2015-03-21
• [Presentation] 縮退ハバード模型におけるs波超伝導状態 (2014)
  • Author(s): 古賀昌久，P. Werner
  • Organizer: 日本物理学会2013年秋季大会
  • Place of Presentation: 中部大学
  • Year and Date: 2014-09-09
• [Presentation] 準周期系を扱う計算手法開発 (2014)
  • Author(s): 竹森那由多，古賀昌久
  • Organizer: 日本物理学会2013年秋季大会
  • Place of Presentation: 中部大学
  • Year and Date: 2014-09-08
• [Presentation] 準周期系における拡張周期アンダーソン模型の解析 (2014)
  • Author(s): 竹村信一，竹森那由多，古賀昌久
  • Organizer: 日本物理学会2013年秋季大会
  • Place of Presentation: 中部大学
  • Year and Date: 2014-09-08
• [Presentation] 準周期性のある系におけるモット転移 (2014)
  • Author(s): 竹森那由多，古賀昌久
  • Organizer: 日本物理学会第69回年次大会
  • Place of Presentation: 東海大学
• [Presentation] 準周期性のある周期アンダーソン模型の解析 (2014)
  • Author(s): 竹村信一，竹森那由多，古賀昌久
  • Organizer: 日本物理学会第69回年次大会
  • Place of Presentation: 東海大学
• [Presentation] 光格子三成分フェルミ粒子系における超流動の安定性 II (2014)
  • Author(s): 岡南佑紀，竹森那由多，古賀昌久
  • Organizer: 日本物理学会第69回年次大会
  • Place of Presentation: 東海大学
• [Presentation] 二次元ペンローズ格子ハバード模型における磁気的性質 (2013)
  • Author(s): 古賀昌久，竹森那由多
  • Organizer: 日本物理学会2013年秋季大会
  • Place of Presentation: 徳島大学
• [Presentation] 二次元ペンローズ格子における局所電子相関 (2013)
  • Author(s): 竹森那由多，古賀昌久
  • Organizer: 日本物理学会2013年秋季大会
  • Place of Presentation: 徳島大学
• [Presentation] クラスター平均場法による直交ダイマー系SrCu2(BO3)2の磁化過程の解析 (2013)
  • Author(s): 鈴木亮太，古賀昌久
  • Organizer: 日本物理学会2013年秋季大会
  • Place of Presentation: 徳島大学
• [Presentation] 光格子三成分フェルミ粒子系における超流動の安定性：量子モンテカルロ法を用いた解析 (2013)
  • Author(s): 岡南佑紀，竹森那由多，古賀昌久
  • Organizer: 日本物理学会2013年秋季大会
  • Place of Presentation: 徳島大学