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物理学系学术讲座
报告题目:
Non-Hermitian Fermi-Dirac Distribution and Applications in Quantum Transport
报告人:
沈培鑫 博士
专家单位:
波兰科学院物理所
报告地点:
海韵物理楼438会议室
报告时间:
2025年10月16日(周四) 10:00
学术系列:
物理学系学术讲座

Abstract: 

In this talk, I will introduce the theory of persistent current transport in non-Hermitian quantum systems, building upon the conventional Hermitian theory of superconducting-normal-superconducting junctions. I will then extend the system to incorporate dissipation using non-Hermitian quantum Hamiltonians. By employing Green’s function formalism, I will show the emergence of a non-Hermitian Fermi-Dirac distribution that allows us to derive an analytical expression for the persistent current that depends solely on the complex spectrum. This formula is applied to two dissipative models: (i) a phase-biased superconducting-normal-superconducting junction, and (ii) a normal mesoscopic ring threaded by a magnetic flux. I will demonstrate that the persistent currents in both systems exhibit no anomalies at emergent exceptional points, whose signatures instead become apparent in the current susceptibility. These results, validated by exact diagonalization, are further extended to include finite temperature and interaction effects. I will conclude by discussing potential applications of this formalism in identifying Majorana zero modes and its connection with symbolic AI.

Reference:

P.-X. Shen, Z. Lu, J. L. Lado, and M. Trif, Non-Hermitian Fermi-Dirac Distribution in Persistent Current Transport, Phys. Rev. Lett. 133, 086301 (2024) (Editors’ Suggestion).


Bio:

Pei-Xin Shen is currently an MSCA-ERA Postdoctoral Fellow at the International Research Centre MagTop at the Institute of Physics, Polish Academy of Sciences. He completed his BS in Astronomy from the College of Physical Science and Technology at Xiamen University in 2017 and obtained his PhD in Physics from the Institute for Interdisciplinary Information Sciences at Tsinghua University in 2022. His current research focuses on open quantum systems, quantum machine learning, and explainable AI for physics.

报告人 沈培鑫 博士 专家单位 波兰科学院物理所
报告地点 海韵物理楼438会议室 报告时间 2025年10月16日(周四) 10:00
学术系列 物理学系学术讲座