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初貝 安弘 ORCID iD icon
筑波大学
数理物質系物理学域長
筑波大学大学院
数理物質科学研究科
物理学専攻 教授
物理学専攻長
初貝写真
Yasuhiro-Nov11-2009
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投稿者 : hatsugai 投稿日時: 2012-03-15 08:44:43 (2281 ヒット)

 Our visiting professor Yshai Avishai is telling us about his recent research on March 15, 2012 (15:00 -17:00). The title of the talk is "Electron in the field of magnetic charge : Tight binding solution and mapping on a realistic physical system". It is understandable for students. Please feel free and come. The detail is here. Contact :Y. Hatsugai.


投稿者 : hatsugai 投稿日時: 2012-02-25 18:00:26 (2462 ヒット)

 We have a distinguished visiting professor Yshai Avishai from Ben Grion University (Israel) staying with us from Feb.12 (2012) to March 31 (2012). He is the APS fellow and also working as one of the regional editors of the Physical Review Letters. 


投稿者 : hatsugai 投稿日時: 2010-07-06 17:30:25 (2886 ヒット)

7月13日(火)D410にて16:00より東大物工の宇田川将文さんに最近のご研究である電荷アイス系の厳密解、量子相転移他に関してのセミナーをお願いすることとなりました。ご関心のある方のご参加をお待ち致しております。M. Udagawa, H. Ishizuka, and Y. Motome, Phys. Rev. Lett. 104, 226405 (2010)  [詳細]  [poster]


投稿者 : hatsugai 投稿日時: 2010-05-31 11:20:27 (3740 ヒット)

5月27日(木)15:00から筑波大学自然系学系棟のD312にて現在東京大学物性研究所に滞在されている Giovanni Vignale 先生に"Many-body effects on the optical and magnetic properties of doped graphene sheets"と題してグラフェンに関する多体効果のお話をしていただくこととなりました。ご関連の皆さまは是非足をお運びください。 [要旨他] [ポスター]


投稿者 : hatsugai 投稿日時: 2009-11-16 19:00:39 (5197 ヒット)

筑波大学ーKEK連携mini研究会(初貝代表基盤研究B共催)


2009年11月27日筑波大学第一エリア自然学系棟B棟1階B119:プログラム [pdf]
・グラフェン、グラファイトをキーワードに実験、理論の皆様の意見交換、研究交流をめざしております。
・参加自由ですので当日直接にご参加いただければ幸いです。多数の方々のご参加をお待ちいたしております。
・場所等に関しましては以下のリンクをご参考にしてください。自然系棟B棟一階です。筑波大学...自然系棟B棟に関しては以下のリンクに詳細がございます。 [地図その他]


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最新ニュース
投稿者 : hatsugai 投稿日時: 2019-11-14 01:28:29 (79 ヒット)

Covalent Organic Frameworks (COF), I understand, is a large molecule where many (block) organic molecules are linked by strong covalent bonds in a periodic or non-periodic manner. It is a nice place where the higher order topological insulating phase is realized as we have pointed out. Then if the COF has boundaries, one can naturally expect edge states/corner states associated with the symmetry protected Berry phases of the bulk. This is correct. One of such a COF, we discussed, is a polymerized triptycene on a decorated star lattice. Our paper ”Flat bands and higher-order topology in polymerized triptycene: Tight-binding analysis on decorated star lattices” by Tomonari Mizoguchi, Mina Maruyama, Susumu Okada, Yasuhiro Hatsugai is for the phenomena and has been published in Physical Review Materials (See also arXiv 1907.06088).


投稿者 : hatsugai 投稿日時: 2019-11-09 07:50:55 (172 ヒット)

We have proposed a new correlated topological phase, "higher-order topological Mott insulator (HOTMI)" where spin-charge separated corner states emerge that are protected by Z3 spin Berry phases of the bulk. It is a generalized bulk-edge correspondence. The article has been published in Phys. Rev. Lett. (also arXiv:1905.03484). Have a look at.


投稿者 : hatsugai 投稿日時: 2019-09-30 11:19:28 (228 ヒット)

Exact flatness of energy bands implies some reasons behind. Here we present one of them, "molecular orbital (MO) representation", which seems to be applied for various classes of tight binding models. Mathematically if the rank of the hamiltonian as a linear operator is less than the number of atomic sites, the kernel of the linear operator has a finite dimension. This is the zero mode flat band. The MO rep. presents nice physical reasons for it. Original proposal by YH with Isao Maruyama in 2011 in EPL and arXiv is counting dimensions of non-orthogonal projections but the hopping of the MO's is allowed as we pointed out (it should be). It's a fun to guess what kinds of the MO representation is possible for a known flat band system. Try ! Also several physical reason why the flat band crosses/touches to dispersive bands in many cases are discussed. Our new paper has appeared in EPL, "Molecular-orbital representation of generic flat-band models", by T. Mizoguchi and Y. Hatsugai , also arXiv.


投稿者 : hatsugai 投稿日時: 2019-09-10 11:03:57 (187 ヒット)

I wrote a small article "So Small Implies So Large: For a Material Design" in the "News and comment" section of the JPSJ in relation to a recent interesting paper by Toshikaze Kariyado. Material deformation induces a gauge field that modifies electronic structure and may result in the Landau levels without breaking time reversal. Have a look at.


投稿者 : hatsugai 投稿日時: 2019-09-09 22:11:58 (185 ヒット)

Our paper "Higher-Order Topological Phase in a Honeycomb-Lattice Model with Anti-Kekulé Distortion" by Tomonari Mizoguchi, Hiromu Araki, and Yasuhiro Hatsugai, has appeared in J. Phys. Soc. Jpn. 88, 104703 (2019). One can access also via arXiv:1906.07928. Z6 quantization in honeycomb structure is the key. Have a look at.


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    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
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    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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