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 2025-09-01 12:00    2025년 가을학기 콜로키움
공지 2025-09-05 11:00    2025년 가을학기 물리학과 특별세미나 (광학/응집물리 분야)
375 2018-10-15 16:00    Universal properties of macroscopic current-carrying systems file
374 2018-04-11 13:30    Probing 3D Structure and Physical Properties of Materials at the Single-Atom Level file
373 2022-06-10 11:00    Record-quality two-dimensional electron systems file
372 2022-05-13 16:00    High-fidelity iToffoli gate for fixed-frequency superconducting qubits file
371 2017-05-12 13:30    Topological Dirac insulator
370 2025-07-03 14:00  Dr. Young-Gwan Choi (Max Planck Institute )  Quantum sensing with NV centers: nanoscale magnetometry file
369 2018-04-11 16:00    Non-Gaussian states of multimode light generated via hybrid quantum information processing file
368 2016-05-13 13:30    Aperiodic crystals in low dimensions
367 2022-08-09 14:00    Quantum biology in fluorescent protein: a new model system to study quantum effects in biology file
366 2018-03-16 16:00    Van der Waals Heterostructures from Quantum Transport to Ultrafast Optoelectronics file
365 2018-03-16 16:00    Van der Waals Heterostructures from Quantum Transport to Ultrafast Optoelectronics file
364 2015-11-06 16:30    Topological Dirac line nodes in centrosymmetric semimetals
363 2019-04-19 14:30    A family of finite-temperature electronic phase transitions in graphene multilayers file
362 2019-11-01 14:30    Squeezing the best out of 2D materials file
361 2017-09-26 11:00    Time-resolved ARPES study of Dirac and topological materials
360 2016-04-08 13:30    Theoretical Overview of Iron-based superconductors and its future
359 2019-06-28 13:30    Magnetic domains and domain wall conduction in pyrochlore iridate thin films and heterostructures file
358 2016-10-27 16:00    Terahertz Metal Optics
357 2016-11-18 10:30    Non-equilibrium many-body spin dynamics in diamond
356 2022-09-15 13:00    AdS black holes: a review