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初貝 安弘 ORCID iD icon
筑波大学
筑波大学大学院
数理物質科学研究科
物理学専攻 教授
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ResercherID: Y.Hatsugai
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Physics of bulk-edge correspondence by Y. Hatsugai

Hiroshima Univ. June 27-29 (2012) : hosted by Prof. Akio Kimura :
Plan & Syllabus

[1] Classical order
Symmetry breaking and low energy excitations
Ref. Talk PDF
[2] Topological order
Quantum liquids, topological order & edge states
Ref. Talk PDF
[3]Various edge states and their physical realization
Ref. Talk PDF
[4]Z2 quantization & topological order parameter
Z2 Berry phases as a singlet order parameter
Ref. paper
Ref. Talk PDF Talk at KITP 2008
[5]Gauge transformation & topological term
Ref. Lorentz force: Analytical mechanics: Univ. of Tsukuba, lecture note (2007) in Japanese
Ref. Path integral & gauge transformation : Univ. Tokyo, lecture note (2004) in Japanese
[6]Local U(1) for continuum & lattice
Peierls substitution
Harper equation
Ref. 2007 Grad. Course at U. Tsukuba
Topological origin of the Hall conductance : Note taken by Ms. JiYoung Kang
[7]The first Chern number as the quantized Hall conductance
Quantization of the first Chern number
Gauge freedom of the Berry connection
Ambiguity of the Berry phase
Gauge invariant form of the Chern numbers
Ref. paper1
Ref. paper2
Ref. paper3
[8]Dirac monopole & degeneracy
Gauge fixing & Dirac strings
The first Chern number & the Berry phase
Ref. paper1
Ref. paper2
Ref. [Y. Hatsugai in Focus issue in topological insulators :NJP][direct link to the paper]
[9]Bulk-edge correspondence
Laughlin argument & quantization
Winding numbers of the edge states
Ref. papers with comments
Ref. Talk PDF
Ref. KOTAIBUTSURI in Japanese
[10]Chiral symmetry & fermion doubling:*
Topological stability of the the massless Dirac cones
Landau levels of the massless Dirac fermions
Ref. article : KOTAI BUTSURI in Japanese
Ref. paper
Ref. 2010 Grad. Course at U. Tsukuba
Graphene and Berry connection : Note taken by Mr. R. Hidekata
[11]Time reversal invariance
Kramers degeneracy & Quaternions
Ref. Talk PDF
Yang monopole & degeneracy with the TR invariance
Ref. [Y. Hatsugai in Focus issue in topological insulators :NJP][direct link to the paper]
TR invariant edge states & Z2
Ref. Talk PDF

*:skipped due to time limitation

前
「物性論におけるトポロジカルな概念とその応用」名古屋大学大学院理学研究科 物理 (平島大 先生 ご紹介)平成22年11月8日ー11日
カテゴリートップ
集中講義
次
「バルクエッジ対応の物理の多様性と普遍性」千葉大学大学院理学研究科 物理 (中山隆史 先生 ご紹介)2015年(平成27年) 7月8日-9日

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今年もやります。まずは量子力学3(遠隔). 冬は 統計力学2 改め物性理論4 (大学院「ベリー接続の理論とバルクエッジ対応」). 令和二年の新年あけましておめでとうございます。今年もあと102日!
最新ニュース
投稿者 : hatsugai 投稿日時: 2020-09-17 11:42:01 (22 ヒット)

As for a topological characterization of a full Liouvillian (including jump term) for the non hermitian fractional quantum Hall states, we are proposing a pseudospin Chern number associated with the Niu-Thouless-Wu type twists in the doubled Hilbert space. Numerical demonstration of the proposal is explicitely given and its validity is discussed. Have a look at "Fate of fractional quantum Hall states in open quantum systems: Characterization of correlated topological states for the full Liouvillian" by Tsuneya Yoshida, Koji Kudo, Hosho Katsura, and Yasuhiro Hatsugai, Phys. Rev. Research 2, 033428 (2020) (open access).


投稿者 : hatsugai 投稿日時: 2020-09-17 11:06:17 (35 ヒット)

The Dirac cone is a typical singular energy dispersion in two dimensions that is a source of various non-trivial topological effects. When realized in real/synthetic materials, it is generically tilted and the equi-energy surface (curve) can be elliptic/hyperbolic (type I/II). The type III Dirac cone is a critical situation between the type I and II that potentially causes various non-trivial physics. As for realization of the type III Dirac cones, we are proposing a generic theoretical scheme without any fine tuning of material parameters . It may also help to synthesize in meta materials. The molecular orbital (MO) construction of the generic flat bands which we are also proposing plays a crutial role. Have a look at "Type-III Dirac Cones from Degenerate Directionally Flat Bands: Viewpoint from Molecular-Orbital Representation" by Tomonari Mizoguchi and Yasuhiro Hatsugai, J. Phys. Soc. Jpn. 89, 103704 (2020) Also arXiv:2007.14643.


投稿者 : hatsugai 投稿日時: 2020-09-08 20:05:59 (44 ヒット)

Motivated by a historical example, the Dirac Hamiltonian as a square-root of the Klein-Gordon Hamiltonian, its lattice analogue has been discussed recently. Zero energy states are shared by the parent and its descendant. The story is more than that. Not necessarily zero energy but its high energy part can also share topological characters. We hereby propose a “square-root higher order topological insulator (square-root HOTI)” when its squared parent is HOTI. Based on the simple observation that square of the decorated honeycomb lattice is given by a decoupled sum of the Kagome and honeycomb lattices, we have demonstrate that the “corner states” of the breezing Kagome lattice with boundaries share topological characters with its descendant as the decorated honeycomb lattice. Have a look at our recent paper, "Square-root higher-order topological insulator on a decorated honeycomb lattice" by Tomonari Mizoguchi, Yoshihito Kuno, and Yasuhiro Hatsugai, to appear in Phys. Rev. A, also arXiv:2004.03235.


投稿者 : hatsugai 投稿日時: 2020-08-16 14:53:28 (171 ヒット)

Adiabatic deformation of gapped systems is a conceptual basis of topological phases. It implies that topological invariants of the bulk described by the Berry connection work as topological order parameters of the phase. This is independent of the well-established symmetry breaking scenario of the phase characterization. Adiabatic heuristic argument for the fractional quantum Hall states is one of the oldest such trials that states the "FRACTIONAL" state is deformed to the “INTEGER”. Although it is intuitive and physically quite natural, there exist several difficulties. How the states with different degeneracy are deformed each other adiabatically? We have clarified the questions and demonstrated this adiabatic deformation on a torus in the paper "Adiabatic heuristic principle on a torus and generalized Streda formula" by Koji Kudo and Yasuhiro Hatsugai , Phys. Rev. B 102, 125108 (2020) (also arXiv:2004.00859) What is deformed continuously is a gap not the states ! This is also sufficient for the topological stability of the Chern number (of the degenerate multiplet) as a topological order parameter. Have a look at.


投稿者 : hatsugai 投稿日時: 2020-07-30 12:47:16 (163 ヒット)

Our article on non-hermitian band touching for strongly correlated systems has been published in PTEP (Progress of Theoretical and Experimental Physics), "Exceptional band touching for strongly correlated systems in equilibrium", by Tsuneya Yoshida, Robert Peters, Norio Kawakami, Yasuhiro Hatsugai. Focusing on the non-hermitian topological phenomena for the equilibrium Green function of correlated electrons, a compact review of the exceptonal band touching that is intrinsic for non-hermitian matrices is described as well. Have a look at.


    検索
    バルク・エッジ対応
    [0] バルクとエッジ
    [1] 集中講義
    [2] 原論文と解説
    [3] トポロジカル秩序とベリー接続:日本物理学会誌 「解説」 [JPS-HP] [pdf]
    [4] "Band gap, dangling bond and spin : a physicist's viewpoint" [pdf] [Web]
    トポロジカル相
    [0]昔の科研費
    科研費 1992年度:電子系スピン系におけるトポロジカル効果
    科研費 1994年度:物性論におけるトポロジーと幾何学的位相
    私の講演ファイルのいくつか
    [1] MIT, Boston (2003)
    [2] APS/JPS March Meeting (2004)
    [3] JPS Fall meeting, JAPAN (2004)
    [4] APS/JPS March meeting (2005)
    [5] JPS Fall meeting (2005):Entanglement
    [6] Superclean workshop, Nasu (2006)
    [7] MPIPKS, Dresden (2006)
    [8] KEK, Tsukuba (2007)
    [9] ETH, Zurich (2008)
    [10] ICREA, Sant Benet (2009)
    [11] JPS Meeting, Kumamoto (2009)
    [12]HMF19, Fukuoka (2010)
    [13] NTU, Singapore (2011)
    [14] ICTP, Trieste (2011)
    [15] Villa conf., Orland (2012)
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