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ResercherID: Y. Hatsugai
投稿者 : hatsugai 投稿日時: 2015-02-19 00:54:08 (997 ヒット)

Massive/massless Dirac cones with/without tilting for 2D semiconductors are described and now the paper has been published in Phys. Rev.B. 4D notations are used for compact derivations of the Landau levels of Dirac cones, extended chiral symmetry and generalized Aharonov-Casher type shifted zero modes. [arXiv:1410.6250] This is a kind of general description of the narrow gap semiconductor as the gapped Dirac cones with tilting. I am sure it can be useful.

投稿者 : hatsugai 投稿日時: 2014-08-19 13:29:55 (730 ヒット)

Takahiro Fukui and I have put a new paper "Entanglement Chern number for an extensive partition of a topological ground state" on the net. It can be a useful tool for several topological phases where conventional Chern numbers are trivial due to some symmetrical constraints. [arXiv]

投稿者 : hatsugai 投稿日時: 2014-08-06 13:13:14 (997 ヒット)

Our recent paper with Toshikaze Kariyado is accepted for publication in Phys. Rev. B where the bulk-edge correspondence is discussed with the Berry connections and adiabatic continuation. As an example, lattice Dirac fermions with 1/4 filling are described with several types of edges where quantized Berry phases in unit of pi/2 is useful. Have a look at [arXiv:1404.4451]

投稿者 : hatsugai 投稿日時: 2014-07-08 18:35:51 (928 ヒット)

Now our paper is published in Phys. Rev. B. It is also on the net arXiv:1403.1648, "Polarization as a topological quantum number in graphene" with Hideo Aok. In the article, one more topological invariant for the Hofstadter problem and graphene is described. Have a look at.

投稿者 : hatsugai 投稿日時: 2014-05-22 13:41:08 (807 ヒット)

第35回 数理の翼 夏季セミナー で8月に話をします。皆さんmotivationが高そうなので楽しみにしています。[概要]

投稿者 : hatsugai 投稿日時: 2014-05-22 13:18:02 (885 ヒット)

We have discussed weak topological phases with super structures using Berry phases. Have a look at our paper with Y.Yoshimura, K.-I. Imura and T. Fukui [arXiv ].

投稿者 : hatsugai 投稿日時: 2014-02-08 11:45:15 (957 ヒット)

大学、大学院での物理学に興味がある方向けの「物理学ガイダンス」(日本評論社)に熱力学に関する小文を書きました。新入生でないかたもどうぞ。[日本評論社] [アマゾン]

投稿者 : hatsugai 投稿日時: 2014-02-03 14:47:48 (780 ヒット)

Physics of graphene の第7章にグラフェンに関するトポロジカルな側面について少し詳しい議論をまとめました。(青木秀夫先生と共著)図書館等でご覧いただければ幸いです。[アマゾン ] で中身が一部ですが、読めます。

投稿者 : hatsugai 投稿日時: 2013-12-31 01:28:58 (1786 ヒット)

We have put a paper on the net. It's about the  symmetry protected quantization and bulk-edge correspondence of massless Dirac fermions. Have a look at [arXiv]. This paper is published in Dec.2013.

投稿者 : hatsugai 投稿日時: 2013-11-25 16:09:20 (1348 ヒット)

Our paper is now online, which is on a doubly degererate manybody state of graphene without spin polarization. "Spin-resolved chiral condensate as a spin-unpolarized ν=0 quantum Hall state in graphene", Phys. Rev. B 88, 195141 (2013)Also have a look at [cond-mat].

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今年もやります。まずは量子力学3. 冬は 統計力学2. 平成30年の新年あけましておめでとうございます。今年もあと346日!
投稿者 : hatsugai 投稿日時: 2017-12-26 01:33:43 (70 ヒット)

最近の研究成果トピックスとして2017年度の科研費ニュース vol.3 にトポロジカル相とバルク・エッジ対応の関係の解説を我々の研究の背景として書きました。予備知識は不要ですのでご興味のある方はご覧下さい。「トポロジカル物質におけるバルク・エッジ対応」

投稿者 : hatsugai 投稿日時: 2017-12-22 19:52:51 (49 ヒット)

Michel Fruchart (Instituut-Lorentz Universiteit, Leiden) will give a talk on Jan.9 (2018), 10:30 am at Rm. B602 by the title Topology of effective evolutions: oriented scattering networks and the phase rotation symmetry

投稿者 : hatsugai 投稿日時: 2017-12-22 11:33:02 (47 ヒット)

Christopher Mudry (Paul Scherrer Institute, Switzerland) gives a talk by the title "Abelian topological order in three-dimensional space" at Rm. B602 from 14:00 on Dec.28, (2017). The detail is here

投稿者 : hatsugai 投稿日時: 2017-11-27 18:03:29 (220 ヒット)

We are organizing an "International workshop : Variety and universality of bulk-edge correspondence 2018 (BEC2018) . Please do not confuse with Bose-Einstein condensation :) Its program is ready.

投稿者 : hatsugai 投稿日時: 2017-10-06 16:36:02 (135 ヒット)

The entanglement Chern numbers is a Chern number of an entanglement Hamiltonian which characterizes topological properties of a topological phase. Starting from a pure state density matrix of the ground state, one may obtain finite temperature (mixed state) density matrix by tracing out parts of the system. If the entanglement hamiltonian has a finite energy gap, the Chern number is well defined by lowering the temperature. We apply the concept for the 3D topological phases.The parity of the number of the Weyl point gives a well defined topological number to distinguish the the state is topologically non trivial. Have a look at arXiv 1708.03722 . The paper has been accepted for publication in Physical Review B.

    [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]
    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
    [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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