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量子材料
New insights and applications of non-Hermitian systems with real-energy spectra
浏覽次數:
主講人: 汪晨(天津大學)
地點: 騰訊會議ID:212-898-792
時間: 2022年9月14日 (周三)15:00
主持 联系人: 何庆林 <qlhe@pku.edu.cn>
主講人簡介: Dr.Chen WANG received his Ph.D. degree from Hong Kong University of Science and Technology in 2016 and joined the department of science of Tianjin University in 2019. His research interests include quantum phase transitions induced by disorders, topological phases, spintronics, and quantum chaos. Recently, he has focused on exploring novel phenomena in non-Hermitian systems.

Abstract:

Generally speaking, the energy spectra of non-Hermitian Hamiltonians are complex. However, for some specific systems, say those with parity-time symmetry, real-energy spectra could emerge and are separated to the domain of complex-energy spectra by exceptional points. The appearance of real-energy spectra (or exceptional points) may lead to distinguished quantum phenomena. This talk will discuss some new insights on non-Hermitian systems with real-energy spectra. Firstly, we give a general outline of how to construct Hermitian chiral boundary states out of topological insulators of non-Hermitian bulk states, even without parity-time symmetry. The transport of such Hermitian chiral boundary states significantly deviates from the paradigm of chiral boundary transport in Hermitian systems. Secondly, the level-repulsion problem near exceptional points is also considered.

References:
[1] H. Yang, C. Wang et al., Phys. Rev. Lett. 121, 197201 (2018).
[2] C. Wang and X. R. Wang, Phys. Rev. B 101, 165114 (2020).
[3] C. Wang and X. R. Wang, Phys. Rev. B 105, 125103 (2022).
[4] C. Wang and X. R. Wang, Phys. Rev. B 106, 045142 (2022).
[5] C. Wang and X. R. Wang, Phys. Rev. B 106, L081118 (2022).