Hall conductance in a weakly time-reversal invariant open system
Abstract
The quantum Hall effect and the quantum anomalous Hall effect both require time-reversal invariance to be broken. We show that non-equilibrium effects can cause Hall physics to arise even when the system is weakly time-reversal symmetric and no magnetic field is applied. In our model, this occurs due to a fermionic subsystem breaking time-reversal invariance even if the system as a whole does not. The fermions receive a TRI-breaking self-energy, caused by interactions with bosonic degrees of freedom in the system and with an external reservoir. As a result, the fermions develop a non-quantized Hall conductance. We demonstrate that, unlike in the equilibrium case, the presence of a mass term is insufficient for the Hall conductance to appear, and wave-function renormalization effects have to be included.
Keywords
Cite
@article{arxiv.2603.11186,
title = {Hall conductance in a weakly time-reversal invariant open system},
author = {Alexander Fagerlund and Christopher Ekman and Rodrigo Arouca},
journal= {arXiv preprint arXiv:2603.11186},
year = {2026}
}
Comments
11+9 pages, 2+2 figures