2021/09/28 更新

写真a

オオツキ ジュンヤ
大槻 純也
OTSUKI Junya
所属
異分野基礎科学研究所 准教授
職名
准教授
外部リンク

学位

  • 博士(理学) ( 東北大学 )

研究キーワード

  • 物性理論

  • 強相関電子系

  • 計算物理

  • 磁性

  • スパースモデリング

  • 重い電子

  • 動的平均場理論

  • 近藤効果

研究分野

  • 自然科学一般 / 磁性、超伝導、強相関系

経歴

  • 岡山大学   異分野基礎科学研究所   准教授

    2018年11月 - 現在

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  • アウグスブルク大学   日本学術振興会海外特別研究員

    2011年8月 - 2013年8月

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  • 東北大学   大学院理学研究科   助教

    2008年4月 - 2018年10月

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  • 東北大学   大学院理学研究科   日本学術振興会特別研究員(DC2)

    2006年4月 - 2008年3月

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所属学協会

委員歴

  • 日本物理学会   領域運営委員(領域8)  

    2010年5月 - 2011年4月   

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    団体区分:学協会

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  • 日本物理学会   領域運営委員(領域8)  

    2010年5月 - 2011年4月   

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    団体区分:学協会

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論文

  • Sparse Modeling in Quantum Many-Body Problems 査読

    Junya Otsuki, Masayuki Ohzeki, Hiroshi Shinaoka, Kazuyoshi Yoshimi

    Journal of the Physical Society of Japan   89 ( 1 )   012001 - 012001   2020年1月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Physical Society of Japan  

    DOI: 10.7566/jpsj.89.012001

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  • Competing d-Wave and p-Wave Spin-Singlet Superconductivities in the Two-Dimensional Kondo Lattice 査読

    Junya Otsuki

    PHYSICAL REVIEW LETTERS   115 ( 3 )   036404-1 - 036404-5   2015年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    The Kondo lattice model describes a quantum phase transition between the antiferromagnetic state and heavy-fermion states. Applying the dual-fermion approach, we explore possible superconductivities emerging due to the critical antiferromagnetic fluctuations. The d-wave pairing is found to be the leading instability only in the weak-coupling regime. As the coupling is increased, we observe a change of the pairing symmetry into a p-wave spin-singlet pairing. The competing superconductivities are ascribed to crossover between small and large Fermi surfaces, which occurs with the formation of heavy quasiparticles.

    DOI: 10.1103/PhysRevLett.115.036404

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  • Superconductivity, antiferromagnetism, and phase separation in the two-dimensional Hubbard model: A dual-fermion approach 査読

    Junya Otsuki, Hartmut Hafermann, Alexander I. Lichtenstein

    PHYSICAL REVIEW B   90 ( 23 )   235132-1 - 235132-12   2014年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    The dual-fermion approach offers a way to perform diagrammatic expansion around the dynamical mean field theory. Using this formalism, the influence of antiferromagnetic fluctuations on the self-energy is taken into account through ladder-type diagrams in the particle-hole channel. The resulting phase diagram for the (quasi-) two-dimensional Hubbard model exhibits antiferromagnetism and d-wave superconductivity. Furthermore, a uniform charge instability, i.e., phase separation, is obtained in the low-doping regime around the Mott insulator. We also examine spin/charge density wave fluctuations including d-wave symmetry. The model exhibits a tendency towards an unconventional charge density wave, but no divergence of the susceptibility is found.

    DOI: 10.1103/PhysRevB.90.235132

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  • Evolution of a Large Fermi Surface in the Kondo Lattice 査読

    Junya Otsuki, Hiroaki Kusunose, Yoshio Kuramoto

    PHYSICAL REVIEW LETTERS   102 ( 1 )   017202   2009年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    The single-particle spectrum of the Kondo lattice model is derived with the use of the continuous-time quantum Monte Carlo method, combined with the dynamical mean-field theory. Crossover behavior is traced quantitatively either to a heavy Fermi-liquid state or to a magnetically ordered state from the local-moment state at high temperatures. The momentum distribution in the low-temperature limit acquires a discontinuity at the location that involves the local-spin degrees of freedom. Even without the charge degrees of freedom for local electrons, the excitation spectra exhibit hybridized bands similar to those in the Anderson lattice. Temperature dependence in the zero-energy component of the self-energy is crucial in forming the Fermi-liquid state with the large Fermi surface.

    DOI: 10.1103/PhysRevLett.102.017202

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  • DCore: Integrated DMFT software for correlated electrons 査読

    Hiroshi Shinaoka, Junya Otsuki, Mitsuaki Kawamura, Nayuta Takemori, Kazuyoshi Yoshimi

    SciPost Physics   10 ( 5 )   2021年5月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Stichting SciPost  

    We present a new open-source program, DCore, that implements dynamical mean-field theory (DMFT).
    DCore features a user-friendly interface based on text and HDF5 files.
    It allows DMFT calculations of tight-binding models to be performed on predefined lattices as well as ab initio models constructed by external density functional theory codes through the Wannier90 package.
    Furthermore, DCore provides interfaces to many advanced quantum impurity solvers such as quantum Monte Carlo and exact diagonalization solvers.
    This paper details the structure and usage of DCore and shows some applications.

    DOI: 10.21468/scipostphys.10.5.117

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  • Spectral properties of heterostructures containing half-metallic ferromagnets in the presence of local many-body correlations 査読

    A. Weh, J. Otsuki, H. Schnait, H. G. Evertz, U. Eckern, A. Lichtenstein, L. Chioncel

    PHYSICAL REVIEW RESEARCH   2 ( 4 )   2020年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    In this work, we investigate models for bulk, bi-, and multilayers containing half-metallic ferromagnets (HMFs), at zero and at finite temperature, in order to elucidate the effects of strong electronic correlations on the spectral properties (density of states). Our focus is on the evolution of the finite-temperature many-body induced tails in the half-metallic gap. To this end, the dynamical mean-field theory (DMFT) is employed. For the bulk, a Bethe lattice model is solved using a matrix product states based impurity solver at zero temperature and a continuous-time quantum Monte Carlo (CT-QMC) solver at finite temperature. We demonstrate numerically, in agreement with the analytical result, that the tails vanish at the Fermi level at zero temperature. In order to study multilayers, taken to be square lattices within the layers, we use the real-space DMFT extension with the CT-QMC impurity solver. For bilayers formed by the HMF with a band or correlated insulator, we find that charge fluctuations between the layers enhance the finite-temperature tails. In addition, in the presence of interlayer hopping, a coherent quasiparticle peak forms in the otherwise correlated insulator. In the multilayer heterostructure setup, we find that by suitably choosing the model parameters, the tails at the HMF-Mott insulator interface can be reduced significantly and that a high spin polarization is conceivable, even in the presence of long-ranged electrostatic interactions.

    DOI: 10.1103/PhysRevResearch.2.043263

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  • Efficient ab initio Migdal-Eliashberg calculation considering the retardation effect in phonon-mediated superconductors 査読

    Tianchun Wang, Takuya Nomoto, Yusuke Nomura, Hiroshi Shinaoka, Junya Otsuki, Takashi Koretsune, Ryotaro Arita

    PHYSICAL REVIEW B   102 ( 13 )   2020年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    We formulate an efficient scheme to perform a Migdal-Eliashberg calculation considering the retardation effect from first principles. While the conventional approach requires a huge number of Matsubara frequencies, we show that the intermediate representation of the Green's function [H. Shinaoka et al., Phys. Rev. B 96, 035147 (2017)] dramatically reduces the numerical cost to solve the linearized gap equation. Without introducing any empirical parameter, we obtain a superconducting transition temperature of elemental Nb (similar to 10 K), which is consistent with experiment. The present result indicates that our approach has a superior performance for many superconductors for which T-c is lower than O(10) K.

    DOI: 10.1103/PhysRevB.102.134503

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  • Optical response in the excitonic insulating state: Variational cluster approach 査読

    Hengyue Li, Junya Otsuki, Makoto Naka, Sumio Ishihara

    Physical Review B   101 ( 12 )   2020年3月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:American Physical Society (APS)  

    DOI: 10.1103/physrevb.101.125117

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    その他リンク: http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevB.101.125117/fulltext

  • Finite Temperature Many-body Effects in Half-metallic Ferromagnets 査読

    Andreas Weh, Junya Otsuki, Liviu Chioncel

    Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2019)   2020年3月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Journal of the Physical Society of Japan  

    DOI: 10.7566/jpscp.30.011005

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  • Sparse sampling and tensor network representation of two-particle Green's functions 査読

    Hiroshi Shinaoka, Dominique Geffroy, Markus Wallerberger, Junya Otsuki, Kazuyoshi Yoshimi, Emanuel Gull, Jan Kuneš

    SciPost Physics   8 ( 1 )   2020年1月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Stichting SciPost  

    Many-body calculations at the two-particle level require a compact
    representation of two-particle Green’s functions. In this paper, we
    introduce a sparse sampling scheme in the Matsubara frequency domain as
    well as a tensor network representation for two-particle Green’s
    functions. The sparse sampling is based on the intermediate
    representation basis and allows an accurate extraction of the
    generalized susceptibility from a reduced set of Matsubara frequencies.
    The tensor network representation provides a system independent way to
    compress the information carried by two-particle Green’s functions. We
    demonstrate efficiency of the present scheme for calculations of static
    and dynamic susceptibilities in single- and two-band Hubbard models in
    the framework of dynamical mean-field theory.

    DOI: 10.21468/scipostphys.8.1.012

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  • SpM: Sparse modeling tool for analytic continuation of imaginary-time Green's function 査読

    Yoshimi Kazuyoshi, Otsuki Junya, Motoyama Yuichi, Ohzeki Masayuki, Shinaoka Hiroshi

    COMPUTER PHYSICS COMMUNICATIONS   244   319 - 323   2019年11月

  • irbasis: Open-source database and software for intermediate-representation basis functions of imaginary-time Green's function 査読

    Chikano Naoya, Yoshimi Kazuyoshi, Otsuki Junya, Shinaoka Hiroshi

    COMPUTER PHYSICS COMMUNICATIONS   240   181 - 188   2019年7月

  • Strong-coupling formula for momentum-dependent susceptibilities in dynamical mean-field theory 査読

    Otsuki Junya, Yoshimi Kazuyoshi, Shinaoka Hiroshi, Nomura Yusuke

    PHYSICAL REVIEW B   99 ( 16 )   2019年4月

  • CT-X: An efficient continuous-time quantum Monte Carlo impurity solver in the Kondo regime 査読

    Yue Changming, Wang Yilin, Otsuki Junya, Dai Xi

    COMPUTER PHYSICS COMMUNICATIONS   236   135 - 152   2019年3月

  • Performance analysis of a physically constructed orthogonal representation of imaginary-time Green's function 査読

    Naoya Chikano, Junya Otsuki, Hiroshi Shinaoka

    PHYSICAL REVIEW B   98 ( 3 )   035104   2018年7月

  • Overcomplete compact representation of two-particle Green's functions 査読

    Hiroshi Shinaoka, Junya Otsuki, Kristjan Haule, Markus Wallerberger, Emanuel Gull, Kazuyoshi Yoshimi, Masayuki Ohzeki

    Physical Review B   97 ( 20 )   205111   2018年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:American Physical Society  

    Two-particle Green's functions and the vertex functions play a critical role in theoretical frameworks for describing strongly correlated electron systems. However, numerical calculations at the two-particle level often suffer from large computation time and massive memory consumption. We derive a general expansion formula for the two-particle Green's functions in terms of an overcomplete representation based on the recently proposed "intermediate representation" basis. The expansion formula is obtained by decomposing the spectral representation of the two-particle Green's function. We demonstrate that the expansion coefficients decay exponentially, while all high-frequency and long-tail structures in the Matsubara-frequency domain are retained. This representation therefore enables efficient treatment of two-particle quantities and opens a route to the application of modern many-body theories to realistic strongly correlated electron systems.

    DOI: 10.1103/PhysRevB.97.205111

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  • Conservation in two-particle self-consistent extensions of dynamical mean-field theory 査読

    Friedrich Krien, Erik G. C. P. van Loon, Hartmut Hafermann, Junya Otsuki, Mikhail I. Katsnelson, Alexander I. Lichtenstein

    PHYSICAL REVIEW B   96 ( 7 )   075155   2017年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    Extensions of dynamical mean-field theory (DMFT) make use of quantum impurity models as nonperturbative and exactly solvable reference systems which are essential to treat the strong electronic correlations. Through the introduction of retarded interactions on the impurity, these approximations can be made two-particle selfconsistent. This is of interest for the Hubbard model because it allows to suppress the antiferromagnetic phase transition in two dimensions in accordance with the Mermin-Wagner theorem, and to include the effects of bosonic fluctuations. For a physically sound description of the latter, the approximation should be conserving. In this paper, we show that the mutual requirements of two-particle self-consistency and conservation lead to fundamental problems. For an approximation that is two-particle self-consistent in the charge and longitudinal spin channels, the double occupancy of the lattice and the impurity is no longer consistent when computed from single-particle properties. For the case of self-consistency in the charge and longitudinal as well as transversal spin channels, these requirements are even mutually exclusive so that no conserving approximation can exist. We illustrate these findings for a two-particle self-consistent and conserving DMFT approximation.

    DOI: 10.1103/PhysRevB.96.075155

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  • Compressing Green's function using intermediate representation between imaginary- ime and real-frequency domains 査読

    Hiroshi Shinaoka, Junya Otsuki, Masayuki Ohzeki, Kazuyoshi Yoshimi

    PHYSICAL REVIEW B   96 ( 3 )   035147   2017年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    Model-independent compact representations of imaginary-time data are presented in terms of the intermediate representation (IR)of analytical continuation. We demonstrate the efficiency of the IR through continuous-time quantum Monte Carlo calculations of an Anderson impurity model. We find that the IR yields a significantly compact form of various types of correlation functions. This allows the direct quantum Monte Carlo measurement of Green's functions in a compressed form, which considerably reduces the computational cost and memory usage. Furthermore, the present framework will provide general ways to boost the power of cutting- edge diagrammatic/quantum Monte Carlo treatments of many-body systems.

    DOI: 10.1103/PhysRevB.96.035147

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  • Sparse modeling approach to analytical continuation of imaginary-time quantum Monte Carlo data 査読

    Junya Otsuki, Masayuki Ohzeki, Hiroshi Shinaoka, Kazuyoshi Yoshimi

    PHYSICAL REVIEW E   95 ( 6 )   061302(R)   2017年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    A data-science approach to solving the ill-conditioned inverse problem for analytical continuation is proposed. The root of the problem lies in the fact that even tiny noise of imaginary-time input data has a serious impact on the inferred real-frequency spectra. By means of a modern regularization technique, we eliminate redundant degrees of freedom that essentially carry the noise, leaving only relevant information unaffected by the noise. The resultant spectrum is represented with minimal bases and thus a stable analytical continuation is achieved. This framework further provides a tool for analyzing to what extent the Monte Carlo data need to be accurate to resolve details of an expected spectral function.

    DOI: 10.1103/PhysRevE.95.061302

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  • Distributed Hybridization Model for Quantum Critical Behavior in Magnetic Quasicrystals 査読

    Junya Otsuki, Hiroaki Kusunose

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   85 ( 7 )   073712   2016年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    A quantum critical behavior of the magnetic susceptibility was observed in a quasicrystal containing ytterbium. At the same time, a mixed-valence feature of Yb ions was reported, which appears to be incompatible with the magnetic instability. We derive the magnetic susceptibility by expressing the quasiperiodicity as the distributed hybridization strength between Yb 4f and conduction electrons. Assuming a wide distribution of the hybridization strength, the most f electrons behave as renormalized paramagnetic states in the Kondo or mixed-valence regime, but a small number of f moments remain unscreened. As a result, the bulk magnetic susceptibility exhibits a nontrivial power-law-like behavior, while the average f-electron occupation is that of mixed-valence systems. This model thus resolves two contradictory properties of Yb quasicrystals.

    DOI: 10.7566/JPSJ.85.073712

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  • Exact Dynamics of Charge Fluctuations in the Multichannel Interacting Resonant Level Model 査読

    Annamaria Kiss, Yoshio Kuramoto, Junya Otsuki

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   84 ( 10 )   104602   2015年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    A modified version of the spinless Anderson model is studied by means of the continuous-time quantum Monte Carlo method. This study is motivated by the peculiar heavy-fermion behavior observed in certain Samarium compounds, which is insensitive to magnetic field. The model involves M channels for conduction electrons, all of which interact with local f electron via the Coulomb repulsion U-fc, while only one channel has hybridization with the local state. The effective hybridization is reduced by the Anderson orthogonality effect, and a quantum critical point occurs with increasing M and/or increasing U-fc. The numerical results at finite temperature of the local charge susceptibility are well fitted by a simple scaling theory for all M. However, the single-particle spectrum is described by a double Lorentzian for M > 1, in contrast with the single Lorentzian with M = 1. A quasi-particle perturbation theory is presented that reproduces the quantum critical point for large M. The quasi-particle theory gives not only the renormalized energy scale, but its extrapolation toward higher energies being consistent with the double Lorentzian spectrum.

    DOI: 10.7566/JPSJ.84.104602

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  • Heavy-Fermion Superconductivity and Localized-Itinerant Crossover in the Kondo Lattice 査読

    Junya Otsuki

    Physics Procedia   75   326 - 331   2015年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Elsevier B.V.  

    Superconductivity in the two-dimensional Kondo lattice model is derived by means of the dual-fermion approach. This framework takes full account of local correlations based on the dynamical mean-field theory and further includes influence of critical antiferromagnetic fluctuations. It is found that pairing with dx2 -y2 symmetry similar to the Hubbard model appears only in the weak-coupling regime. As the coupling is increased, we observe transition to p-wave spin-singlet superconductivity. The emergence of the unconventional p-wave pairing is ascribed to formation of large Fermi surface, which embodies itinerancy of f electrons.

    DOI: 10.1016/j.phpro.2015.12.199

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  • Scaling theory vs exact numerical results for spinless resonant level model 査読

    Annamária Kiss, Junya Otsuki, Yoshio Kuramoto

    Journal of the Physical Society of Japan   82 ( 12 )   124713   2013年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    This paper studies the charge Kondo effect in the (spinless) interacting resonant level model (IRLM) by means of the continuous-time quantum Monte Carlo method. The charge Kondo effect may be relevant to certain Samarium compounds with peculiar heavy-fermion behavior. We use double expansion with respect to Coulomb interaction Uf c and hybridization V. Exact dynamics and thermodynamics of the IRLM are derived numerically for a wide range of Uf c with a given value of V. As Uf c becomes negative, a quantum critical point is found in excellent agreement with a simple scaling formula that deals with V in the lowest-order, and Uf c up to infinite order. As Uf c becomes positive and large, however, exact numerical results deviate from lower order scaling results. In particular, the renormalized hybridization increases monotonically with increasing Uf c in contrast with the scaling theory that suggests another quantum critical point. © 2013 The Physical Society of Japan.

    DOI: 10.7566/JPSJ.82.124713

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  • Dynamical mean-field theory for quantum spin systems: Test of solutions for magnetically ordered states 査読

    Junya Otsuki, Yoshio Kuramoto

    Physical Review B   88   024427   2013年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1103/PhysRevB.88.024427

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  • Numerical Solution of the t-J Model with Random Exchange Couplings in d=∞ Dimensions 査読

    Junya Otsuki, Dieter Vollhardt

    Physical Review Letters   110 ( 19 )   196407   2013年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1103/PhysRevLett.110.196407

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  • Scaling between periodic Anderson and Kondo lattice models 査読

    R. Dong, J. Otsuki, S. Y. Savrasov

    PHYSICAL REVIEW B   87 ( 15 )   155106   2013年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    Continuous-time quantum Monte Carlo method combined with dynamical mean field theory is used to calculate both periodic Anderson model (PAM) and Kondo lattice model (KLM). Different parameter sets of both models are connected by the Schrieffer-Wolff transformation. For degeneracy N = 2, a special particle-hole symmetric case of PAM at half filling which always fixes one electron per impurity site is compared with the results of the KLM. We find a good mapping between PAM and KLM in the limit of large on-site Hubbard interaction U for different properties like self-energy, quasiparticle residue and susceptibility. This allows us to extract quasiparticle mass renormalizations for the f electrons directly from KLM. The method is further applied to higher degenerate case and to realistic heavy fermion system CeRhIn5 in which the estimate of the Sommerfeld coefficient is proven to be close to the experimental value. DOI: 10.1103/PhysRevB.87.155106

    DOI: 10.1103/PhysRevB.87.155106

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  • Charge order in Kondo lattice systems 査読

    Robert Peters, Shintaro Hoshino, Norio Kawakami, Junya Otsuki, Yoshio Kuramoto

    PHYSICAL REVIEW B   87 ( 16 )   165133   2013年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    Charge order is a commonly observed phenomenon in strongly correlated materials. However, most theories are based on a repulsive intersite Coulomb interaction in order to explain charge order. Here we show that only due to local interactions, charge order is favorable in heavy fermion systems at quarter filling. The driving force is the Kondo effect, which leads to a nonlinear dependence on the filling of the lattice site for the energy gain. We use dynamical mean field theory combined with numerical renormalization group to demonstrate the existence of charge order at quarter filling for a Kondo lattice model. DOI: 10.1103/PhysRevB.87.165133

    DOI: 10.1103/PhysRevB.87.165133

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  • Resolution of Entropy ln root 2 by Ordering in Two-Channel Kondo Lattice 査読

    Shintaro Hoshino, Junya Otsuki, Yoshio Kuramoto

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   82 ( 4 )   044707   2013年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    Peculiar property of electronic order is clarified for the two-channel Kondo lattice. With two conduction electrons per site, the order parameter is a composite quantity involving both local and itinerant degrees of freedom. In contrast to the ordinary Kondo lattice, a heavy electron band is absent above the transition temperature, but is rapidly formed below it. The change of entropy associated with the ordering is found to be close to ln root 2 per site. This entropy corresponds to the residual entropy in a two-channel Kondo impurity, which has been regarded as due to localized free Majorana particles. The present composite order is interpreted as instability of Majorana particles toward non-Kramers conduction electrons plus heavy fermions that involve localized electrons.

    DOI: 10.7566/JPSJ.82.044707

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  • Spin-boson coupling in continuous-time quantum Monte Carlo 査読

    Junya Otsuki

    Physical Review B - Condensed Matter and Materials Physics   87 ( 12 )   125102   2013年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A vector bosonic field coupled to the electronic spin is treated by means of the continuous-time quantum Monte Carlo method. In the Bose-Kondo model with a sub-Ohmic density of states ρB(ω)ωs with s=0.2, two contributions to the spin susceptibility, the Curie term T-1 and the term T-s due to bosonic fluctuations, are observed separately. This result indicates the existence of a residual moment and a hidden critical behavior. By including hybridization with itinerant electrons, a quantum critical point is identified between this local-moment state and the Kondo singlet state. It is demonstrated that the energy scale of the bosonic fluctuations is not affected by the quantum phase transition. © 2013 American Physical Society.

    DOI: 10.1103/PhysRevB.87.125102

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  • Two-particle self-consistent approach to unconventional superconductivity 査読

    Junya Otsuki

    PHYSICAL REVIEW B   85 ( 10 )   104513   2012年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    A nonperturbative approach to unconventional superconductivity is developed based on the idea of two-particle self-consistent (TPSC) theory by Vilk and Tremblay. A sum rule, which the momentum-dependent pairing susceptibility satisfies, is derived. An effective pairing interaction between quasiparticles is determined so that the susceptibility should fulfill this exact sum rule, in which fluctuations belonging to different symmetries couple at finite momentum. It is demonstrated that the mode coupling between d- wave and s- wave pairing fluctuations leads to suppression of the d- wave fluctuation near the Mott insulator.

    DOI: 10.1103/PhysRevB.85.104513

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  • Mott insulator in two-channel Kondo lattice 査読

    S. Hoshino, J. Otsuki, Y. Kuramoto

    Journal of Physics: Conference Series   391 ( 1 )   012155 - 012155   2012年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Institute of Physics Publishing  

    The Mott insulator is found in the two-channel Kondo lattice by using the dynamical mean-field theory combined with continuous-time quantum Monte Carlo method. At quarter filling of two conduction bands, the paramagnetic state shows metal-insulator crossover with increasing the coupling constant at low temperatures. The insulating state is explained by the strong coupling limit, where the system is effectively interpreted as the half-filled Hubbard model. It is shown that the present Mott insulating state is well described by the Hubbard I approximation. © Published under licence by IOP Publishing Ltd.

    DOI: 10.1088/1742-6596/391/1/012155

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  • Diagonal Composite Order in a Two-Channel Kondo Lattice 査読

    Shintaro Hoshino, Junya Otsuki, Yoshio Kuramoto

    PHYSICAL REVIEW LETTERS   107 ( 24 )   247207   2011年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    A novel type of symmetry breaking is reported for the two-channel Kondo lattice where conduction electrons have spin and orbital (channel) degrees of freedom. Using the continuous-time quantum Monte Carlo and the dynamical mean-field theory, a spontaneous breaking of the orbital symmetry is observed. The tiny breakdown of orbital occupation number, however, vanishes if the conduction electrons have the particle-hole symmetry. The proper order parameter instead is identified as a composite quantity representing the orbital-selective Kondo effect. The single-particle spectrum of the selected orbital shows insulating property, while the other orbital behaves as a Fermi liquid. This composite order is the first example of odd-frequency order other than off-diagonal order (superconductivity), and is a candidate of hidden order in f-electron systems.

    DOI: 10.1103/PhysRevLett.107.247202

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  • Multiple quantum phase transitions of plutonium compounds 査読

    Munehisa Matsumoto, Quan Yin, Junya Otsuki, Sergey Yu Savrasov

    PHYSICAL REVIEW B   84 ( 4 )   041105(R)   2011年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    We show by quantum Monte Carlo simulations of realistic Kondo lattice models derived from electronic-structure calculations that multiple quantum critical points can be realized in plutonium-based materials. We place representative systems, including PuCoGa(5), on a realistic Doniach phase diagram and identify the regions where the magnetically mediated superconductivity could occur. The solution of an inverse problem to restore the quasiparticle renormalization factor for f electrons is shown to be sufficiently good to predict the trends among Sommerfeld coefficients and magnetism. A suggestion on the possible experimental verification for this scenario is given for PuAs.

    DOI: 10.1103/PhysRevB.84.041105

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  • Spin Density Wave Driven by Quadrupolar Kondo Effect in Two-channel Kondo Lattice 査読

    Shintaro Hoshino, Junya Otsuki, Yoshio Kuramoto

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80 ( Supplement A )   SA135   2011年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    A new type of magnetism is found in the two-channel Kondo lattice where each non-Kramers doublet is coupled with two conduction bands by the orbital exchange J. The quadrupolar Kondo effect leads to an SDW state in the case of quarter filled bands, i.e., one conduction electron per site. This order is understood from the strong coupling limit with respect to J. Using the continuous-time Monte Carlo method combined with the DMFT at finite temperature T, the phase diagram is constructed in the J-T plane for the quarter filled case.

    DOI: 10.1143/JPSJS.80SA.SA135

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  • Electronic Orders Induced by Kondo Effect in Non-Kramers f-Electron Systems 査読

    Yoshio Kuramoto, Shintaro Hoshino, Junya Otsuki

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80 ( Supplement A )   SA018   2011年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    This paper clarifies the microscopic nature of the staggered scalar order, which is specific to even number off electrons per site. In such systems, crystalline electric field (CEF) can make a singlet ground state. As exchange interaction with conduction electrons increases, the CEF singlet at each site gives way to Kondo singlets. The collective Kondo singlets are identified with itinerant states that form energy bands. Near the boundary of itinerant and localized states, a new type of electronic order appears with staggered Kondo and CEF singlets. We present a phenomenological three-state model that qualitatively reproduces the characteristic phase diagram, which have been obtained numerically with use of the continuous-time quantum Monte Carlo combined with the dynamical mean-field theory. The scalar order observed in PrFe4P12 is ascribed to this staggered order accompanying charge density wave (CDW) of conduction electrons. Accurate photoemission and tunneling spectroscopy should be able to probe sharp peaks both below and above the Fermi level in the ordered phase.

    DOI: 10.1143/JPSJS.80SA.SA018

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  • Continuous-Time Quantum Monte Carlo Study of Local Non-Fermi Liquid State in the Multichannel Anderson Model 査読

    Junya Otsuki

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80 ( Supplement A )   SA129   2011年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    The impurity Green's function G(f) in the local non-Fermi liquid state is evaluated by means of the continuous-time quantum Monte Carlo method extended to the multichannel Anderson model. For N = M (where N and M are numbers of spin components and channels, respectively), G(f) is expressed as -ImG(f)(omega + i0) = c - b vertical bar omega vertical bar(1/2), and the zero-frequency value c depends only on N (= M). A corresponding impurity self-energy at low frequencies is composed of two parts: a resonance term related to c, and a non-Fermi liquid term proportional to vertical bar omega vertical bar(1/2). The characteristic energy scale is discussed in terms of the non-Fermi liquid term in the self-energy.

    DOI: 10.1143/JPSJS.80SA.SA129

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  • Microscopic Mechanism for Staggered Scalar Order in PrFe4P12 査読

    Shintaro Hoshino, Junya Otsuki, Yoshio Kuramoto

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   80 ( 3 )   033703   2011年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    A microscopic model is proposed for the scalar order in PrFe4P12 where f(2) crystalline electric field (CEF) singlet and triplet states interact with two conduction bands. By combining dynamical mean-field theory and the continuous-time quantum Monte Carlo, we obtain an electronic order with staggered Kondo and CEF singlets with the total conduction number being unity per site. The ground state becomes semimetallic provided that the two conduction bands have different occupation numbers. This model naturally explains experimentally observed properties in the ordered phase of PrFe4P12 such as the scalar order parameter, temperature dependence of the resistivity, field-induced staggered moment, and inelastic features in neutron scattering. The Kondo effect plays an essential role for ordering, in strong contrast with ordinary magnetic orders by the RKKY interaction.

    DOI: 10.1143/JPSJ.80.033703

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  • Staggered order with itinerant and localized singlets in generalized Kondo lattice 査読

    S. Hoshino, J. Otsuki, Y. Kuramoto

    Journal of Physics: Conference Series   273 ( 1 )   012034 - 012034   2011年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Institute of Physics Publishing  

    The generalized Kondo lattice where even number of localized electrons are coupled with two conduction bands is investigated using the dynamical mean-field theory combined with continuous-time quantum Monte Carlo method. The crystalline electric field (CEF) singlet-triplet states are taken for localized states. With one conduction electron per site, a staggered order with Kondo and CEF singlets arises. Nature of the electronic order is studied in terms of the local susceptibility. The effective CEF splitting in one sublattice remains almost the same as the original CEF splitting, while the other sublattice looks like Kondo singlets. Hence, this electronic order is interpreted as alternating sites of itinerant and localized singlet states. © Published under licence by IOP Publishing Ltd.

    DOI: 10.1088/1742-6596/273/1/012034

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  • Magnetic quantum critical point and dimensionality trend in cerium-based heavy-fermion compounds 査読

    Munehisa Matsumoto, Myung Joon Han, Junya Otsuki, Sergey Yu. Savrasov

    PHYSICAL REVIEW B   82 ( 18 )   180515(R)   2010年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    We present realistic Kondo-lattice simulation results for the recently discovered heavy-fermion antiferromagnet CePt(2)In(7) comparing with its three-dimensional counterpart CeIn(3) and the less two-dimensional ones, Ce-115's. We find that the distance to the magnetic quantum critical point is the largest for CeIn3 and the smallest for Ce-115's, and CePt(2)In(7) falls in between. We argue that the trend in quasi-two-dimensional materials stems from the frequency dependence of the hybridization between cerium 4f electrons and the conduction bands.

    DOI: 10.1103/PhysRevB.82.180515

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  • Effect of Disorder on Fermi Surface in Heavy Electron Systems 査読

    Junya Otsuki, Hiroaki Kusunose, Yoshio Kuramoto

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   79 ( 11 )   114709   2010年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    The Kondo lattice model with substitutional disorder is studied with attention to the size of the Fermi surface and the associated Dingle temperature. The model serves for understanding heavy-fermion Ce compounds alloyed with La according to substitution CexLa1-x. The Fermi surface is identified from the steepest change of the momentum distribution of conduction electrons, and is derived at low enough temperature by the dynamical mean-field theory (DMFT) combined with the coherent potential approximation (CPA). The Fermi surface without magnetic field increases in size with decreasing x from x = 1 (Ce end), and disappears at such x that gives the same number of localized spins as that of conduction electrons. From the opposite limit of x = 0 (La end), the Fermi surface broadens quickly as x increases, but stays at the same position as that of the La end. With increasing magnetic field, a metamagnetic transition occurs, and the Fermi surface above the critical field changes continuously across the whole range of x. The Dingle temperature takes a maximum around x = 0.5. Implication of the results to experimental observation is discussed.

    DOI: 10.1143/JPSJ.79.114709

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  • Electronic Order with Staggered Kondo and Crystalline Electric Field Singlets 査読

    Shintaro Hoshino, Junya Otsuki, Yoshio Kuramoto

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   79 ( 7 )   074720   2010年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    Novel electronic order is found theoretically for a system where even number of localized electrons per site are coupled with conduction electrons. For precise quantitative study, a variant of the Kondo lattice model is taken with crystalline electric field (CEF) singlet and triplet states for each site. Using the dynamical mean-field theory combined with the continuous-time quantum Monte Carlo method, a staggered order with alternating Kondo and CEF singlets is identified for a case with one conduction electron per site being distributed in two conduction bands each of which is quarter-filled. This electronic order accompanies a charge density wave (CDW) of conduction electrons that accumulate more on Kondo-singlet sites than on CEF-singlet sites. Possible relevance of the present order to the scalar order in PrFe4P12 is discussed.

    DOI: 10.1143/JPSJ.79.074720

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  • Itinerant Antiferromagnetism in Infinite Dimensional Kondo Lattice 査読

    Shintaro Hoshino, Junya Otsuki, Yoshio Kuramoto

    Phys. Rev. B   81 ( 11 )   113108   2010年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1103/PhysRevB.81.113108

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  • First-Principles Simulations of Heavy Fermion Cerium Compounds Based on the Kondo Lattice 査読

    Munehisa Matsumoto, Myung Joon Han, Junya Otsuki, Sergey Y. Savrasov

    PHYSICAL REVIEW LETTERS   103 ( 9 )   096403   2009年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    We propose a new framework for first-principles calculations of heavy-fermion materials. These are described in terms of the Kondo lattice Hamiltonian with the parameters extracted from a realistic density functional based calculation which is then solved using continuous-time quantum Monte Carlo method and dynamical mean field theory. As an example, we show our results for the Neacuteel temperatures of cerium-122 compounds (CeX(2)Si(2) with X=Ru, Rh, Pd, Cu, Ag, and Au) where the general trend around the magnetic quantum critical point is successfully reproduced. Our results are organized on a universal Doniach phase diagram in a semiquantitative way.

    DOI: 10.1103/PhysRevLett.103.096403

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  • Continuous-Time Quantum Monte Carlo Approach to Singlet-Triplet Kondo Systems 査読

    S. Hoshino, J. Otsuki, Y. Kuramoto

    J. Phys. Soc. Jpn.   78 ( 7 )   074719   2009年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1143/JPSJ.78.074719

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  • The Kondo Lattice Model in Infinite Dimensions: II. Static Susceptibilities and Phase Diagram 査読

    Junya Otsuki, Hiroaki Kusunose, Yoshio Kuramoto

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   78 ( 3 )   034719   2009年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    Magnetic and charge susceptibilities in the Kondo lattice are derived by the continuous-time quantum Monte Carlo (CT-QMC) method combined with the dynamical mean-field theory. For a weak exchange coupling J and near half filling of the conduction band, antiferromagnetic transition occurs as signalled by divergence of the staggered magnetic susceptibility with lowering temperature. With increasing J, the Kondo effect Suppresses the divergence, and the critical value of J agrees well with Doniach's estimate which considers the RKKY interaction as competing with the Kondo effect. For low density of conduction electrons, a ferromagnetic ordering is observed where Doniach's estimate does not work. Around quarter tilling, a charge-density-wave (CDW) transition is found. The CDW is interpreted from the strong-coupling limit in terms of effective repulsion between Kondo singlets.

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  • The Kondo Lattice Model in Infinite Dimensions I. Formalism 査読

    J. Otsuki, H. Kusunose, Y. Kuramoto

    J. Phys. Soc. Jpn.   78 ( 1 )   014702   2008年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1143/JPSJ.78.014702

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  • Magnetic excitations in heavy electron state of filled skutterudite PrxLa1-xFe4P12 (x=1.00 and 0.85) 査読

    Kazuaki Iwasa, Lijie Hao, Tomoo Hasegawa, Kenji Horiuchi, Youichi Murakami, Junya Otsuki, Yoshio Kuramoto, Masahumi Kohgi, Keitaro Kuwahara, Hitoshi Sugawara, Yuji Aoki, Hideyuki Sato

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   77 ( 6 )   063706   2008年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    PrFe4P12 exhibits clear heavy electron behaviors as well as the phase transition to an antiferro-type ordering of 4f electron state. In this paper, we report on inelastic neutron scattering results for powdered samples of PrxLa1-xFe4P12 (x = 1.00 and 0.85). A clear quasielastic magnetic response is observed, and no distinct signal is seen for crystal-field (CF) excitations in the heavy electron state. A model with strong hybridization between conduction electrons and Pr3+ 4f(2) electrons [J. Otsuki et al.: J. Phys. Soc. Jpn. 74 (2005) 200 and 2082] is consistent with the observed magnetic response. This result shows that the heavy electron behavior of PrxLa1-xFe4P12 (x = 1.00 and 0.85) originates from the Kondo effect associated with low-lying singlet-triplet CF states.

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  • Continuous-time quantum Monte Carlo method for the Coqblin-Schrieffer model 査読

    Junya Otsuki, Hiroaki Kusunose, Philipp Werner, Yoshio Kuramoto

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   76 ( 11 )   114707   2007年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    An impurity solver based on a continuous-time quantum Monte Carlo method is developed for the Coqblin-Schrieffer model. The Monte Carlo simulation does not encounter a sign problem for antiferromagnetic interactions, and accurately reproduces the Kondo effect. Our algorithm can deal with an arbitrary number N of local degrees of freedom, becomes more efficient for larger values of N, and is hence suitable for models with orbital degeneracy. The dynamical susceptibility and the impurity t-matrix are derived with the aid of the Pade approximation for various values of N, and good agreement is found with other methods and available exact results. We point out that the Korringa-Shiba relation needs correction for a finite value of the exchange interaction.

    DOI: 10.1143/JPSJ.76.114707

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  • Excitonic bound state in the extended Anderson model with c-f Coulomb interaction 査読

    Junya Otsuki

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   76 ( 6 )   2007年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    The Anderson model with the Coulomb interaction between the local and conduction electrons is studied in the semiconducting phase. Based on a perturbation theory from the atomic limit, leading contributions for the c-f Coulomb interaction are incorporated as a vertex correction to hybridization. An analytical solution shows that the effective attraction in the intermediate states leads to a bound state localized at the local electron site. Self-consistent equations are constructed as an extension of the non-crossing approximation (NCA) to include the vertex part yielding the bound state. A numerical calculation demonstrates the excitonic bound state inside the semiconducting gap for single-particle excitations, and a discontinuity at the gap edge for magnetic excitations.

    DOI: 10.1143/JPSJ.76.064707

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  • The de Haas-van Alphen effect in Kondo systems with crystalline electric field 査読

    Junya Otsuki, Hiroaki Kusunose, Yoshio Kuramoto

    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS   310 ( 2 )   425 - 427   2007年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    The effective mass probed by the de Haas-van Alphen oscillations is studied for a model Ce system under magnetic field higher than the Kondo energy. In the mean-field theory, the mass enhancement per Ce ion in the periodic system is identical with that in the dilute system. With decreasing magnetic field, the effective mass tends to diverge corresponding to a formation of the Kondo ground state. The effective mass can be very different between up and down spins depending on the nature of the 4f wave functions. (c) 2006 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.jmmm.2006.10.265

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  • Extension of the non-crossing approximation for the Anderson model with finite coulomb repulsion 査読

    Junya Otsuki, Yoshio Kuramoto

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   75 ( 6 )   2006年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    The non-crossing approximation (NCA) is generalized for the Anderson model with finite Coulomb repulsion U. Resummation of infinite number of terms is performed so as to incorporate all leading contributions in the limit of large degeneracy of the local states. With negligible weight of the doubly occupied local states in equilibrium, the extension is achieved through simple modifications of the lowest order formulae. The single-particle excitation spectrum is calculated with almost the same computational effort as in the original NCA. The present scheme reproduces the scaling behavior of the Kondo resonance in the density of states, and gives reasonable description of thermodynamics of the finite-U Anderson model over a wide range of temperature.

    DOI: 10.1143/JPSJ.75.064707

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  • Hybridization and multipole orders of 4f electrons in Pr skutterudites 査読

    Yoshio Kuramoto, Annamaria Kiss, Junya Otsuki, Hiroaki Kusunose

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   75   209 - 214   2006年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    Characteristics of hybridization and multipole orders of 4f-electrons in Pr skutterudites are explained in terms of a pseudo-quartet composed of crystalline electric field (CET) singlet and the triplet. It is shown that the contrasting behaviors observed in PrFe4P12 and PrOs4Sb12 are ascribed to the difference in triplet Wave functions and the CEF splittings. Since a macroscopic degeneracy remains even in the ordered phase with the F-3-type antiferro-quadrupole (AFQ) order, a model with strong AFQ fluctuation and static monopole/hexadecapole order is proposed for PrFe4 P12 The remaining cubic symmetry explains qualitatively the behavior of staggered magnetization observed by NMR and neutron scattering. For identification of possible hexadecapole orders in PrFe4P12, and PrRu4P12, eightfold intensity pattern is predicted in the azimuthal angle scan of resonant X-ray scattering. In PrOs4Sb12, the ferromagnetic exchange coupling with the conduction band does not lead to magnetic Kondo effect, but a momentum-dependent quadrupole coupling can give rise to enhanced effective mass, is should be sensitive to disorder.

    DOI: 10.1143/JPSJS.75S.209

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  • Dynamics of the singlet-triplet system coupled with conduction spins -application to Pr skutterudites- 査読

    Junya Otsuki, Hiroaki Kusunose, Yoshio Kuramoto

    Journal of the Physical Society of Japan   74 ( 7 )   2082 - 2089   2005年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Dynamics of the singlet-triplet crystalline electric field (CEF) system at finite temperatures is discussed by use of the non-crossing approximation. Even though the Kondo temperature is smaller than the excitation energy to the CEF triplet, the Kondo effect appears at temperatures higher than the CEF splitting, and accordingly only quasi-elastic peak is found in the magnetic spectra. On the other hand, at lower temperatures the CEF splitting suppresses the Kondo effect and inelastic peak develops. The broad quasi-elastic neutron scattering spectra observed in PrFe4P12 at temperatures higher than the quadrupole order correspond to the parameter range where the CEF splittings are unimportant. ©2005 The Physical Society of Japan.

    DOI: 10.1143/JPSJ.74.2082

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  • Theory of crystalline electric field and Kondo effect in Pr skutterudites 査読

    Junya Otsuki, Hiroaki Kusunose, Yoshio Kuramoto

    Journal of the Physical Society of Japan   74 ( 1 )   200 - 208   2005年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Possible Kondo effect in Pr skutterudite is studied with attention to characteristic features of low-lying crystalline electric field (CEF) levels and the conduction band. A mechanism for the small CEF splitting between a singlet and a triplet is proposed as combination of the point-charge interaction and hybridization of 4f with ligand p states. Provided 4f 3 configurations dominate over 4f 1 as intermediate states, p-f hybridization favors the triplet, while point-charge interaction favors the singlet. For realistic parameters for hybridization as well as 4f 1 and 4f 3 levels, these singlet and triplet can form a nearly degenerate pseudo-quartet. It is found that one of two spin 1/2 objects composing the pseudo-quartet has a ferromagnetic exchange, while the other has an antiferromagnetic exchange with conduction electrons. The magnitude of each effective exchange depends strongly on a parameter characterizing the triplet wave function under the T h symmetry. It is argued that differences of this parameter among Pr skutterdudites are responsible for the apparent diversity of their physical properties. Numerical renormalization group is used to derive the renormalization flows going toward singlet, doublet, triplet or quaret according to the CEF splitting and exchange interactions. ©2005 The Physical Society of Japan.

    DOI: 10.1143/JPSJ.74.200

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  • 温度グリーン関数の情報圧縮に基づく高速量子多体計算法 査読

    品岡寛, 近野直也, 野本拓也, 大槻純也, 吉見一慶

    個体物理   56 ( 6 )   301 - 314   2021年6月

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  • 最大エントロピー法でいいの?―スパースモデリングの量子多体論への応用― 招待 査読

    大槻純也, 大関真之, 品岡 寛, 吉見一慶

    固体物理   53 ( 4 )   173 - 188   2018年4月

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    記述言語:日本語  

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  • 多体効果の最前線 招待

    大槻純也

    物性研究 電子版   6 ( 1 )   061205   2017年2月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

    DOI: 10.14989/225166

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  • 長距離相関効果を考慮した動的平均場法の拡張理論 ―強相関電子系の遍歴・局在双対性と超伝導― 招待 査読

    大槻純也, 楠瀬博明

    固体物理   51 ( 4 )   223 - 236   2016年4月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(商業誌、新聞、ウェブメディア)   出版者・発行元:アグネ技術センター  

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  • ダイアグラム展開に基づく連続時間量子モンテカルロ法 招待

    楠瀬博明, 大槻純也

    物性研究   94 ( 4 )   404 - 439   2010年7月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)   出版者・発行元:物性研究刊行会  

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  • Dynamics of singlet-triplet crystalline electric field levels in Pr skutterudites 査読

    Junya Otsuki, Hiroaki Kusunose, Yoshio Kuramoto

    PHYSICA B   378-380   244 - 245   2006年5月

  • Self-Consistent Perturbation Theory for Thermodynamics of Magnetic Impurity Systems 査読

    Otsuki Junya, Kusunose Hiroaki, Kuramoto Yoshio

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN SUPPLEMENT   75   256 - 258   2006年1月

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  • Hybridization effects and multipole orders in Pr skutterudites 査読

    Yoshio Kuramoto, Junya Otsuki, Annamária Kiss, Hiroaki Kusunose

    Progress of Theoretical Physics Supplement   160   134 - 154   2005年

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    記述言語:英語  

    Theoretical account is given of 4f-electron dynamics and multipole orders in Pr skutterudites with particular attention to (i) mechanism of the crystalline electric field (CEF) splitting leading to a pseudo-quartet ground state
    (ii) Kondo effect due to exchange interactions involving the pseudo-quartet
    (iii) multipole orders in the lattice of the pseudo-quartet in magnetic field. Competition between the point-charge interaction and hybridization between 4f and conduction electrons is identified as the key for controlling the CEF splitting. It is found that one of two pseudo-spins forming the pseudo-quartet has a ferromagnetic exchange, while the other has an antiferromagnetic exchange with conduction electrons. The Kondo effect is clearly seen in the resistivity calculated by the NCA, provided the low-lying triplet above the singlet is mainly composed of the Γ4-type wave functions. If the weight of the Γ5-type is large in the triplet, the Kondo effect does not appear. This difference caused by the nature of the triplet explains the presence of the Kondo effect in PrFe4P12, and its absence in PrOs4Sb12. By taking the minimal model with antiferro-quadrupole (AFQ) and ferro-type intersite interactions for dipoles and octupoles between nearest-neighbors, the mean-field theory reproduces the overall feature of the multiple ordered phases in PrFe4P12. The AFQ order with the Γ3-type symmetry is found to be stable only as a mixture of O2 0 and O2 2 components.

    DOI: 10.1143/PTPS.160.134

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講演・口頭発表等

  • コンプトン散乱データからのフェルミ面再構成:圧縮センシングの応用

    大槻純也

    日本物理学会  2021年9月23日 

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    開催年月日: 2021年9月20日 - 2021年9月23日

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  • 動的平均場理論による非局所相関の計算とGPU化 招待

    大槻純也

    物性研究所スパコン共同利用・CCMS合同研究会「計算物質科学の新展開2020」  2020年12月21日 

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    開催年月日: 2020年12月21日 - 2020年12月22日

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  • 強相関電子系に対する理論計算法の最近の発展:動的平均場法とスパースモデリング

    大槻純也

    物理談話会  2020年12月17日 

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    開催年月日: 2020年12月17日

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  • 動的平均場法に基づく非局所相互作用の新しい公式とその応用

    大槻純也

    J-Physics領域全体会議  2020年1月8日 

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    開催年月日: 2020年1月6日 - 2020年1月8日

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  • 動的平均場理論による非局所相互作用の見積もりについて

    大槻純也

    第3回動的平均場近似計算に関する情報交流会  2019年12月3日 

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    開催年月日: 2019年12月2日 - 2019年12月3日

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  • Spatial Correlations and Superconductivity in Dynamical Mean-Field Theory 招待

    大槻 純也

    International Conference on Strongly Correlated Electron Systems (SCES2019)  2019年9月27日 

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    記述言語:英語   会議種別:口頭発表(招待・特別)  

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  • Strong-coupling formula for momentum-dependent susceptibilities in the dynamical mean-field theory

    大槻 純也

    J-Physics 2019 International Conference  2019年9月18日 

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    記述言語:英語   会議種別:ポスター発表  

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  • 多極子秩序の第一原理計算の現状報告

    大槻 純也

    J-Physics 地域研究会  2019年6月7日 

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    記述言語:日本語   会議種別:口頭発表(一般)  

    開催地:九州工業大学  

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  • Strong-coupling formula of momentum-dependent susceptibilities in dynamical mean-field theory

    大槻 純也

    International Conference on Frontiers of Correlated Electron Sciences (FCES19)  2019年5月29日 

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    記述言語:英語   会議種別:ポスター発表  

    開催地:東京大学  

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  • 動的平均場法を用いた理論計算の現状とコバルト化合物への応用可能性 招待

    大槻 純也

    第2回コバルト研究会  2019年3月28日 

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    記述言語:日本語   会議種別:口頭発表(招待・特別)  

    開催地:東北大学  

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  • Recent progress on dynamical mean-field calculations of spin, orbital and multipolar ordering 招待

    大槻 純也

    Emergent Condensed-Matter Physics 2019 (ECMP2019)  2019年3月18日 

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    記述言語:英語   会議種別:口頭発表(招待・特別)  

    開催地:広島  

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  • スピン・軌道感受率の動的平均場計算に関する最近の進展 招待

    大槻 純也

    量研・原子力機構・兵県大合同物性コロキウム  2019年1月28日 

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    会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

    開催地:Spring-8  

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  • 強相関化合物における長距離秩序の理論予測にむけた最近の進展 招待

    大槻 純也

    物性セミナー  2019年1月25日 

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    記述言語:日本語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

    開催地:東京大学駒場キャンパス  

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  • 多極子秩序の第一原理計算に向けた最近の進展

    大槻 純也

    J-Physicsトピカルミーティング  2019年1月21日 

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    開催地:明治大学  

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  • Recent progress on dynamical mean-field calculations of multipole ordering

    大槻 純也

    International Workshop on j-fermion Physics and Materials  2018年12月4日 

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    記述言語:英語  

    開催地:ニュージーランド オタゴ大学  

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  • 強相関領域における動的平均場理論ベーテ・サルピーター方程式の近似解

    大槻 純也

    日本物理学会  2018年9月9日 

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    開催地:同志社大学  

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  • Strong-coupling formula of spin and orbital susceptibilities in the dynamical mean-field theory 招待

    大槻 純也

    Condensed Matter Theory Seminar  2018年9月6日 

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    記述言語:英語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

    開催地:岡山大学  

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  • 動的平均場法に基づく強相関化合物の電子状態と多極子揺らぎ計算の最近の進展 招待

    大槻 純也

    基礎科学セミナー  2018年7月23日 

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    会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

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  • 動的平均場法に基づく多極子揺らぎ計算の最近の進展

    大槻 純也

    物性理論コロキウム  2018年7月9日 

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    会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

    開催地:新潟大学  

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  • Strong-coupling solution of the Bethe-Salpeter equation in DMFT

    大槻 純也

    第2回 動的平均場近似計算に関する情報交流会  2018年6月18日 

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    記述言語:日本語  

    開催地:埼玉大学  

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  • 動的平均場法に基づく多極子秩序の微視的理論

    大槻 純也

    J-Physics 平成30年度領域全体会議  2018年5月25日 

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    会議種別:口頭発表(一般)  

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  • 量子多体物理におけるスパースモデリングの方法

    大槻 純也

    J-Physics 平成29年度領域全体会議  2018年3月15日 

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    会議種別:口頭発表(一般)  

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  • Superconductivity and magnetic ordering emerging when itinerant and localized natures of electrons cooperate 招待

    大槻 純也

    Emergent Condensed-Matter Physics 2018  2018年3月6日 

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    会議種別:口頭発表(招待・特別)  

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  • 量子多体問題へのデータ科学の応用 招待

    大槻 純也

    計算物質科学イノベーションキャンプ2018  2018年1月23日 

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    会議種別:口頭発表(招待・特別)  

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  • 量子多体論における機械学習とデータ科学の方法

    大槻 純也

    スパースモデリングを基軸にした計算物性理論交流会  2017年11月29日 

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    会議種別:口頭発表(一般)  

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  • DFT+DMFT approach to multipolar ordering in f-electron materials

    J-Physics 2017: International Workshop on Multipole Physics and Related Phenomena  2017年9月24日 

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    会議種別:ポスター発表  

    開催地:日本国 岩手  

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  • Superconductivity and multipole ordering in f-electron compounds studied by dual-fermion approach and LDA+DMFT 招待

    3rd International Workshop on Dynamical Mean-Field Approach for Strongly Correlated Materials  2017年9月19日 

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    会議種別:口頭発表(招待・特別)  

    開催地:ドイツ ドレスデン  

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  • Sparse modeling approach to analytical continuation and dimensionality reduction of imaginary-time Green function 招待

    Trends in Theory of Correlated Materials 2017  2017年9月10日 

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    会議種別:口頭発表(招待・特別)  

    開催地:日本国 つくば  

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  • Intermediate representation between Matsubara and retarded Green functions: Analytical continuation and compression

    The 28th International Conference on Low Temperature Physics  2017年8月9日 

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    会議種別:ポスター発表  

    開催地:スウェーデン ヨーテボリ  

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  • Sparse modeling approach to analytical continuation and compression of imaginary-time quantum Monte Carlo data 招待

    Machine Learning and Many-Body Physics  2017年6月28日 

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    会議種別:口頭発表(招待・特別)  

    開催地:中国 北京  

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  • 重い電子系におけるf電子の遍歴性・局在性と超伝導 招待

    超伝導研究の最先端: 多自由度、非平衡、電子相関、トポロジー、人工制御  2017年6月19日 

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    会議種別:口頭発表(招待・特別)  

    開催地:京都  

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  • A new method for analytical continuation and compression of imaginary-time quantum Monte Carlo data 招待

    大槻 純也

    2017年6月5日 

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    記述言語:英語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

    開催地:理化学研究所  

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  • スパースモデリングの量子多体問題への応用:量子モンテカルロデータの解析接続と次元圧縮 招待

    大槻 純也

    量子物理学・ナノサイエンスセミナー  2017年4月19日 

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    開催地:東京工業大学  

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  • 虚時間グリーン関数の新しい圧縮手法と解析接続:LDA+DMFT法による磁性と超伝導の第一原理計算に向けて

    J-Physics トピカルミーティング「局在多極子と伝導電子の相関による新現象」  2017年4月17日 

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    会議種別:口頭発表(一般)  

    開催地:柏  

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  • スパースモデリングによる量子モンテカルロデータの解析接続

    物性研究所スパコン共同利用・CCMS合同研究会「計算物質科学の今と未来」  2017年4月3日 

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    会議種別:ポスター発表  

    開催地:柏  

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  • スパースモデリングを応用した量子モンテカルロ虚時間データの実振動数への解析接続 招待

    情報・データ科学との連携・融合による物性物理・量子化学の新展開  2017年3月22日 

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    会議種別:口頭発表(招待・特別)  

    開催地:神戸  

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  • スパースモデリングを利用した量子モンテカルロデータの解析接続

    大関真之, 品岡寛, 吉見一慶

    日本物理学会  2017年3月17日 

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    会議種別:口頭発表(一般)  

    開催地:大阪  

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  • Review on theories beyond DMFT 招待

    動的平均場近似計算に関する情報交流会  2017年2月16日 

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    会議種別:口頭発表(招待・特別)  

    開催地:東京  

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  • 動的平均場法の拡張による強相関系の超伝導理論と第一原理計算への応用 招待

    量子多体問題と磁性材料をつなぐミニワークショップ  2017年1月17日 

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    会議種別:口頭発表(招待・特別)  

    開催地:つくば  

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  • Superconductivity emerging when itinerant and localized natures of electrons cooperate 招待

    14th Bilateral Japanese-German Symposium  2016年9月26日 

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    会議種別:口頭発表(招待・特別)  

    開催地:日本国 札幌  

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  • LDA+DMFT法によるCe1-2-2系化合物の電子構造計算

    品岡寛, 播磨尚朝, 酒井治

    日本物理学会  2016年9月13日 

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    会議種別:口頭発表(一般)  

    開催地:金沢大  

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  • Yb系準結晶化合物の磁気揺らぎと混合価数状態の理論

    楠瀬博明

    日本物理学会  2016年9月13日 

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    会議種別:口頭発表(一般)  

    開催地:金沢  

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  • 多体効果の最前線 招待

    J-Physics 若手夏の学校  2016年8月8日 

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    会議種別:口頭発表(招待・特別)  

    開催地:和歌山  

    講義

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  • Perturbation Theory around the Dynamical Mean-Field Approximation and its Application to Heavy-Fermion Superconductivity 招待

    The 2nd Conference on Condensed Matter Physics  2016年7月20日 

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    会議種別:口頭発表(招待・特別)  

    開催地:中国 南京  

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  • Yb系準結晶化合物の磁気揺らぎと価数状態に関する理論

    J-Physics 領域全体研究会  2016年5月26日 

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    会議種別:ポスター発表  

    開催地:札幌  

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  • 電子の遍歴・局在双対性を考慮した重い電子超伝導の微視的理論

    J-Physics 領域全体研究会  2016年5月26日 

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    会議種別:口頭発表(招待・特別)  

    開催地:札幌  

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  • Perturbation Theory around the Dynamical Mean-Field Approximation: New Insight into Heavy-Fermion Superconductivities 招待

    Trends in Theory of Correlated Materials  2016年5月22日 

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    会議種別:口頭発表(招待・特別)  

    開催地:スイス チューリッヒ  

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  • 重い電子系における遍歴・局在双対性と超伝導 招待

    量子物質研究の最前線  2015年12月8日 

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    会議種別:口頭発表(招待・特別)  

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  • Dual-fermion approach to heavy-fermion superconductivity in two-dimensional Kondo lattice

    2nd International Workshop on Dynamical Mean-Field Approach for Strongly Correlated Materials  2015年9月29日 

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    会議種別:ポスター発表  

    開催地:ドイツ ドレスデン  

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  • Yb系準結晶化合物の非フェルミ液体的振る舞いに関する考察:乱れの効果

    楠瀬博明

    日本物理学会 2015年秋季大会  2015年9月16日 

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    会議種別:口頭発表(一般)  

    開催地:大阪  

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  • 2次元近藤格子におけるd波およびp波スピン一重項超伝導

    日本物理学会 2015年秋季大会  2015年9月16日 

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    会議種別:口頭発表(一般)  

    開催地:大阪  

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  • Dual-fermion approach to superconductivity in strongly correlated systems: Application to Hubbard and Kondo lattice models 招待

    The 1st Conference on Condensed Matter Physics  2015年7月15日 

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    会議種別:口頭発表(招待・特別)  

    開催地:中国 北京  

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  • Dual-fermion approach to superconductivities in the two-dimensional Kondo lattice

    International Conference on Magnetism 2015  2015年7月5日 

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    会議種別:ポスター発表  

    開催地:スペイン バルセロナ  

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  • f電子の遍歴・局在と量子臨界点近傍の超伝導

    多自由度と相関効果が生み出す超伝導の新潮流  2015年6月9日 

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    会議種別:ポスター発表  

    開催地:京都  

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  • デュアルフェルミオン法による2次元近藤格子模型の超伝導揺らぎ

    日本物理学会 第70回年次大会  2015年3月21日 

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    会議種別:口頭発表(一般)  

    開催地:東京  

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  • Dual fermion approach to strongly correlated electron systems 招待

    International Workshop on New Frontier of Numerical Methods for Many-Body Correlations  2015年2月18日 

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    会議種別:口頭発表(招待・特別)  

    開催地:日本国 東京  

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  • Dual fermion approach to the two-dimensional Kondo lattice 招待

    Workshop on recent developments in the Kondo problem  2015年1月9日 

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    会議種別:口頭発表(招待・特別)  

    開催地:日本国 千葉  

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  • デュアルフェルミオン法による2次元近藤格子模型の超伝導

    第4回 強相関電子系理論の最前線  2014年12月19日 

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    会議種別:口頭発表(招待・特別)  

    開催地:日本国 和歌山  

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  • Dual fermion approach to unconventional superconductivity and spin/charge density waves 招待

    Novel Quantum States in Condensed Matter 2014  2014年11月17日 

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    会議種別:口頭発表(招待・特別)  

    開催地:日本国 京都  

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  • 動的平均場理論の基礎と最近の発展

    CMSI夏の学校  2014年8月18日 

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    会議種別:口頭発表(招待・特別)  

    開催地:滋賀  

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  • Dual fermion approach to unconventional superconductivity and spin/charge density wave

    13th Bilateral German-Japanese Symposium: Interplay of Spin- and Orbital Degrees of Freedom in Strongly Correlated Electron Systems  2014年7月13日 

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    会議種別:口頭発表(招待・特別)  

    開催地:ドイツ ミュンヘン  

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  • Dual fermion approach to unconventional superconductivity and spin/charge density wave

    ISSP International Workshop: New Horizon of Strongly Correlated Physics  2014年6月16日 

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    会議種別:口頭発表(招待・特別)  

    開催地:日本国 千葉  

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  • 連続時間量子モンテカルロ法を用いた重い電子系の理論的研究

    日本物理学会 第69回年次大会  2014年3月27日 

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    会議種別:口頭発表(招待・特別)  

    開催地:神奈川  

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  • 動的平均場理論の拡張による非従来型超伝導

    H. Hafermann, A. I. Lichtenstein

    日本物理学会 第69回年次大会  2014年3月27日 

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    会議種別:口頭発表(一般)  

    開催地:神奈川  

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  • 動的平均場理論の拡張による非従来型超伝導

    第3回 強相関電子系理論の最前線 ‒ 若手によるオープン・イノベーション ‒  2013年12月16日 

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    会議種別:口頭発表(招待・特別)  

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  • t-J model with random coupling: Numerical solution in infinite dimensions

    Dieter Vollhardt

    Dynamical Mean-Field Approach for Strongly Correlated Materials  2012年9月25日 

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    会議種別:ポスター発表  

    開催地:ドイツ Dresden  

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  • Two-particle self-consistent approach to anisotropic superconductivity

    International Workshop Functionality from Heterostructures  2011年10月10日 

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    会議種別:ポスター発表  

    開催地:オーストリア Obergurgl  

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  • Two-particle self-consistent approach to anisotropic superconductivity

    Japan Swiss Workshop 2011  2011年9月16日 

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    会議種別:口頭発表(招待・特別)  

    開催地:スイス チューリッヒ  

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  • Continuous-Time Quantum Monte Carlo Study of Heavy Fermions with f2 Configuration

    International Conference on Heavy Electrons 2010  2010年9月17日 

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    会議種別:ポスター発表  

    開催地:日本国 東京  

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  • Continuous-Time Quantum Monte Carlo Study of Heavy-Fermion System with f2 Configuration

    New Trends in Theory of Correlated Materials 2010  2010年9月8日 

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    会議種別:口頭発表(招待・特別)  

    開催地:日本国 千葉  

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  • Magnetic and charge instabilities in the Kondo lattice

    Workshop on recent developments in dynamical mean field theory  2009年9月28日 

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    会議種別:口頭発表(招待・特別)  

    開催地:スイス チューリッヒ  

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受賞

  • 第8回(2014年)日本物理学会若手奨励賞(領域8)

    2014年3月   日本物理学会   連続時間量子モンテカルロ法を用いた重い電子系の理論的研究

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    受賞区分:国内外の国際的学術賞  受賞国:日本国

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  • JPSJ Papers of Editors' Choice

    2013年3月   日本物理学会   J. Phys. Soc. Jpn. 82 (2013) 044707

    S. Hoshino, J. Otsuki, Y. Kuramoto

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    受賞区分:学会誌・学術雑誌による顕彰  受賞国:日本国

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  • 第2回泉萩会奨励賞

    2010年10月   泉萩会  

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    受賞国:日本国

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担当授業科目

  • コンピュータ物理学2 (2021年度) 3・4学期  - 火1,火2

  • コンピュータ物理学2A (2021年度) 第3学期  - 火1,火2

  • コンピュータ物理学2B (2021年度) 第4学期  - 火1,火2

  • 凝縮系物理学 (2021年度) 後期  - 水3,水4

  • 学際基礎科学概論1 (2021年度) 前期  - 水1,水2

  • 強相関電子系物理学 (2021年度) 前期  - その他

  • 統計力学演習2 (2021年度) 3・4学期  - 金3,金4

  • 統計力学演習2A (2021年度) 第3学期  - 金3,金4

  • 統計力学演習2B (2021年度) 第4学期  - 金3,金4

  • 統計力学1A (2021年度) 第1学期  - 金1,金2

  • 統計力学1B (2021年度) 第2学期  - 金1,金2

  • 統計力学I (2021年度) 1・2学期  - 金1,金2

  • 量子多体物理学演習 (2021年度) 通年  - その他

  • コンピュータ物理学2 (2020年度) 3・4学期  - 火1,火2

  • コンピュータ物理学2A (2020年度) 第3学期  - 火1,火2

  • コンピュータ物理学2B (2020年度) 第4学期  - 火1,火2

  • 凝縮系物理学 (2020年度) 後期  - 水2,水3

  • 学際基礎科学概論1 (2020年度) 前期  - 水1,水2

  • 強相関電子系物理学 (2020年度) 前期  - その他

  • 物理科学入門 (2020年度) 3・4学期  - 火3,火4

  • 物理科学入門A (2020年度) 第3学期  - 火3,火4

  • 物理科学入門B (2020年度) 第4学期  - 火3,火4

  • 統計力学演習2 (2020年度) 3・4学期  - 金3,金4

  • 統計力学演習2A (2020年度) 第3学期  - 金3,金4

  • 統計力学演習2B (2020年度) 第4学期  - 金3,金4

  • 統計力学1A (2020年度) 第1学期  - 金1,金2

  • 統計力学1B (2020年度) 第2学期  - 金1,金2

  • 統計力学I (2020年度) 1・2学期  - 金1,金2

  • 自然科学入門1(物理学) (2020年度) 第1学期  - 火3,火4

  • 自然科学入門2(物理学) (2020年度) 第2学期  - 火3,火4

  • 量子多体物理学演習 (2020年度) 前期

  • 量子多体物理学演習 (2020年度) 通年  - その他

  • 量子多体物理学演習 (2020年度) その他  - その他

▼全件表示

 

メディア報道

  • 【研究成果】重い電子超伝導の理論計算に成功 ー奇妙な性質を持った超伝導ー

    2015年8月4日

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    本研究科物理学専攻 大槻純也助教は、これまで理論的な扱いが難しかった希土類化合物における超伝導を扱う数値計算手法を開発し、大規模数値計算によって、これまでに確認されていない奇妙な超伝導状態が希土類化合物において実現する可能性があることを明らかにしました。この成果は2015年7月15日にPhysical Review Letters誌に掲載されました(DOI:http://dx.doi.org/10.1103/PhysRevLett.115.036404)。

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