visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2024-10-21 13:00 
연사 Geonhwi Hwang (Hokkaido University) 
장소 E6-2 #3441 

 

Non-Hermitian topological phases have recently garnered increasing attention since they possess richer topological properties than those in Hermitian systems. In the theory of topological phases, the bulk-edge correspondence (BEC) takes one of the most important roles. For the topological phases characterized by the point gap, which is an energy gap unique to non-Hermitian systems, the BEC has been established for the systems with periodic boundary systems (PBC), semi-infinite boundary conditions (SIBC), and open boundary conditions (OBC) as detailed in [1]. Further, in Hermitian systems, the BEC is extended to the junction systems consisting of two subsystems with independent topological invariant. In the non-Hermitian system, however, the BEC has not been discussed for the junction systems so far. In this work, we clarify the BEC for point gap topological phases in junction systems [2]. As shown in Fig. 1, we consider a one-dimensional junction system with PBC where two ends of a subsystem are connected to those of the other subsystem so that the whole system forms a ring geometry. Each subsystem has asymmetric hopping terms and its own point-gap topological invariant. We confirm that the spectrum for the junction system with PBC appears on the complex-energy plane where the difference in winding number for each subsystem is non-trivial. We further study eigenstates in the junction systems and find that unique ''non-Hermitian proximity effects'' occur near the interface. These results establish the BEC for the point-gap topological phases in junction systems with PBC, which is regarded as a natural extension inferred from the BEC in Hermitian systems. We also examine the junction system with OBC then confirm that the spectrum for the junction system with OBC appears on and inside the spectrum for the corresponding junction system with PBC. We further extend the BEC for point-gap topological phases to multi-segmented junction systems, which may provide deeper insights into spectrum and localization phenomena across various models.

 
[1] N. Okuma, K. Kawabata, K. Shiozaki, and M. Sato, Phys. Rev. Lett. 124, 086801 (2020).
[2] G. Hwang and H. Obuse, Phys. Rev. B 108, L121302 (2023).
 
Contact: Sungbin Lee(sungbin@kaist.ac.kr)

 

번호 날짜 연사 제목
공지 2026-03-09 16:00    2026년 봄학기 콜로키움
공지 2026-03-05 16:00    2026년 봄학기 물리학과 특별세미나 (광학/응집물리 분야)
658 2026-04-03 15:00  Dr. Siheon Ryee(Univ. of Hamburg)  Superconductivity and Correlations in Emerging Quantum Materials file
657 2026-04-01 16:00  Dr. Dongjoon Song (University of British Columbia)  Unlocking the new frontier of novel quantum materials research using state of the art floating zone technique file
656 2026-03-31 14:00  Prof. Daniel Sando (University of Canterbury)  Crafting novel low-symmetry and topological structures in ferroelectric oxide thin films and superlattices file
655 2026-02-25 16:00  Dr. Minjae Kim (KIST)  Collective excitations and order parameter dynamics in quantum materials file
654 2026-02-25 10:00  Prof. Gen Tatara (RIKEN Center for Emergent Matter Science)  Lectures on spintronics and theoretical approaches in spin transport file
653 2026-02-19 10:00  Prof. Ron Lifshitz (Tel Aviv University)  What is a Crystal? A new paradigm for an old question file
652 2026-02-09 16:00  Dr. Dae-Yun Kim (Samsung Advanced Institute of Technology)  Introduction to Superconducting Qubits file
651 2026-02-04 16:00  Prof. Ivan Savenkon (Guangdong Technion Israel Institute of Technology)  Coherence and quantum coherence of exciton-polariton lasers file
650 2026-02-02 14:00  Dr. Junho Seo (Max Planck Institute)  Emergent transport phenomena in quantum materials driven by topology file
649 2026-01-21 14:00  Dr. Kanghyun Chu (University of Bern, Switzerland)  Periodic Hirshfeld atom refinement Applications to borane and borate compounds file
648 2025-12-29 10:30  Dr. Chul-Hee Min (Norwegian University of Science and Technology)  Emergence of Holstein polarons in semimetallic TmSe1-xTex Probing Weyl nodes in Trigonal Weyl Semimetal PtBi2₂ by ARPES file
647 2025-12-12 12:00  Kohji Nakamura (Mie University) 외 6명  Mini-workshop on first-principles computations of magnetic materials file
646 2025-12-09 16:00  Dr. Moosung Lee (Universität Stuttgart, Germany)  Inverse photonic design for exploring quantum motion in levitated optomechanics file
645 2025-12-05 10:30  박경덕 교수 (연세대)  Quantum for AI, AI for Quantum file
644 2025-12-05 09:00  박지호 박사 (ETRI)  광기반 양자 얽힘을 활용한 양자 정보 기술 소개 file
643 2025-12-03 11:00  Kyoung Hun Oh (MIT) *박사과정  Ultrafast light-driven dynamics of moiré charge density waves in EuTe4 file
642 2025-11-21 15:00  김병윤 교수 (KAIST 전 창업원장)  Physics for Future Innovation Seminar Series file
641 2025-11-21 10:00    Korea-Luxembourg Workshop: Quantum computing and related quantum technologies file