News

Anyon superconductivity revisited : talk by Koji Kudo

2023.2.9

Next Wednesday, Feb. 15 (2023), Koji Kudo (Penn state) visits us and will be telling on anyon superconductivity. The talk is hybrid. [Detail] For the zoom link, contact me (email). Speaker: Koji Kudo...

Topological strucure can be fragile against interactions

2023.1.26

Topological protection of singularities for the non-Hermitian problem is one of the recent focuses in condensed matter physics. Exceptional points and rings with symmetry constraints are typical examp...

Seminar by Tonomari Mizoguchi

2022.12.12

Coming Wed. afternoon, 13:00, Dec.14, Tomonari Mizoguchi (Univ. Tsukuba) will be telling us about his work in collaboration with N. Okuma (Kyoto Univ.). The seminar is in a hybrid format. Please conta...

Reduction of non-Hermitian 1D topology with interaction

2022.11.28

Topological protection for topological systems may change by the inclusion of particle-particle interaction, which is known as "reduction phenomena." Here we have pointed out its possibilities for 1-d...

TTQM2022

2022.10.31

Swiss-Japan　bilateral　workshop "Trends in the Theory of Quantum Materials 2022 (TTQM2022)" @ ETH, Zurich, is ready after a three-year break due to COVID-19. Thanks for the arrangement!

Bulk-edge correspondence in electric circuits of topological pump

2022.9.29

One of the recent wisdom for topological phases is the use of a classical system as a quantum simulator. The Hofstadter butterfly associated with topological phase transitions is realized in electric ...

Localization 2022

2022.8.31

Localisation 2022 T. Mizoguchi and Y. Hatsugai, "Gap opening and emergent critical states in a random-phase molecular-orbital model", Localisation 2022, Aug.25-30 (2022) T. Kuroda, T. Mizoguchi, and Y...

Adiabatic connection with spin

2022.7.29

Adiabatic connection of the gapped many-body states is a conceptual background of the topological phases. Historical and more than successful examples are given by various fractional quantum Hall stat...

BEC seminar by Koji Kudo, Aug.10, 2022

2022.7.28

On Aug.10 (Wed) 2022 at 11:am Japan time, Koji Kudo at Penn State will be telling us about his recent study by a title : "Exactly solvable model for non-Abelian quasiparticle states." Join us on zoom....

“b 2– 4 ac” formula with rotation symmetry

“b ²– 4 ac” formula with rotation symmetry

2022.6.2

The discriminant is a generalization of the　"b 2- 4 ac" formula that everybody knows, which tells us the degeneracy of the (secular) equation. Then it is natural the discriminant is useful for the stu...

Random flatbands are special

2022.4.6

Recent wisdom for the construction of flat bands is applicable even with randomness. Characterization of special features of the random flat bands has been successfully done by using machine learning....

APS March meeting 2022

2022.3.8

APS March meeting, March 14-18 2022, Chicago USA

Heat escapes fast due to bulk-edge correspondence

2022.2.25

Analyzing a diffusion equation of alternative metals, rapid heat conduction to the heat bath due to edge states is predicted. The edge states are predicted by the bulk topological invariant as a typic...

Exact correlation of correlation

2022.2.20

Once one admits the electronic state is described by the molecular-orbitals (MOs), the system has flat bands when the number of MOs is less than the total number of atoms. Then it is natural the elect...

Discriminant and symmetry

2022.2.18

As widely accepted, the degeneracy of eigenvalues of the Hamiltonian is a singular point, which is the source of the non-trivial topology. Then it is more than natural that the discriminant of the sec...

Non-hermitian topology in game theory

2022.1.21

The use of topological invariants for the characterization of material phases has been quite successful. Non-trivial topology is reflected by physical observables near the boundaries of systems as a b...

First/second order topology in honeycomb lattice

2022.1.11

The Haldane model with Kekulè distortion possesses various phases characterized by different topology with specific boundary states. Competition between the 1st/2nd order topology (1D/0D boundary stat...

Flux attachement and bulk-edge correspondence

2021.12.28

Adiabatic insertion of the Aharonov-Bohm flux through two pinholes introduces charge transport between them when the system is topologically non-trivial. This is the Laughlin argument. The defects/pin...

Young Scientist Award of the Physical Society of Japan (2022)

2021.11.14

Tsuneya Yoshida (assistant Prof.) is awarded the "Young Scientist Award of the Physical Society of Japan (2022)" Pioneering works on non-Hermitian strongrly correlated phenomena "Non-Hermitian perspec...

BEC Seminar 14:00-15:00 Nov.26 (2021) Yoshiyuki Matsuki

2021.11.3

Yoshiyuki Matsuki will be telling us on their recent work. (Zoom)。Join us by contacting Y. Hatsugai. "Fractal defect states in the Hofstadter butterﬂy"

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