Berry curvature effects on time refraction

by Prof. Qian Niu（牛谦） (University of Science and Technology of China)

Monday 26 Jan 2026, 10:00 → 11:00 Asia/Shanghai

Tsung-Dao Lee Institute/N6F-N600 - Lecture Room (Tsung-Dao Lee Institute)

Host: Prof. Hong Ding

Venue: TDLI Meeting Room N600   

Tencent Meeting link: https://meeting.tencent.com/dm/znXbhv53HaaZ  

Meeting ID: 677822673, no password

 

Abstract:

We demonstrate that there exist frequency domain Berry curvature in the wave function of photons in dispersive optical systems. This property arises from the frequency dispersion of its dielectric function, which makes Maxwell equations a non-standard eigenvalue equation, with the eigenvalue (frequency) appearing inside the operator itself. We study this new Berry curvature effect on time refraction of magnetoplasmon-polariton as an example. It can induce deflection in the trajectory of a photon and make the ray swing.

 

Biography:

Prof. Qian Niu obtained a B.S. from Peking University in 1981. He went to the University of Washington for graduate studies, and received his Ph.D. in physics in 1985. He was Sid W. Richardson Foundation Regents Chair in Physics at the University of Texas at Austin, USA before joining University of Science and Technology of China as a Distinguished Chair Professor in 2021. He has worked on the theories on quantum Hall effects, quasicrystals, ultracold atoms, spin transport, and graphene materials, with an emphasis on topological and geometric phase effects in quantum transport. He has published ~280 peer reviewed papers, including 84 in Physical Review Letters, 3 in Science, 5 in Nature and its subsidiaries, 1 each in Review of Modern Physics, Physics Today, and Physics World. These papers have generated over 33,000 citations (with an H index of 83). He is a Fellow of the American Physical Society.