Anomalous wavepacket dynamics and quantum geometry in non-Hermitian systems

by Prof. Roni Ilan

TAU

at Condensed Matter Seminar

Mon, 12 May 2025, 11:10
Sacta-Rashi Building for Physics (54), room 207

Abstract

Berry phases strongly affect the properties of crystalline materials, giving rise to modifications of the semiclassical equations of motion that govern
wave-packet dynamics. In non-Hermitian systems, generalizations of the Berry connection have been argued to characterize the topology of these systems. Since non-Hermitian Hamiltonians could be relevant for many types of open and lossy systems, it is important to understand how these new quantities enter equations of motion for semi-classical wavepackets. Since, generally, for non-Hermitian systems the adiabatic theorem fails, this poses a challenge to the theory. I will discuss how to define observables and the conditions under which we can still apply the single band limit, and introduce the type of anomalous terms that may appear in the equation of motion, which are present already in one-dimensional systems. I will also discuss the conditions for observing these anomalous contributions and potential extensions of the formalism to include complex electric fields and magnetic fields. These reveal the role of the quantum metric in the dynamics and offer a possible generalization to the orbital magnetic moment.

Created on 05-05-2025 by Bar Lev, Yevgeny (ybarlev)
Updaded on 05-05-2025 by Bar Lev, Yevgeny (ybarlev)