Dynamically Induced Exceptional Phases in Quenched Interacting Semimetals

TL;DR

This paper demonstrates how quenching certain correlated semimetals near critical points can dynamically induce topologically robust non-Hermitian phases with exceptional degeneracies, observable in spectral and momentum distribution functions.

Contribution

It introduces a mechanism for dynamically creating non-Hermitian topological phases in quenched interacting systems, linking critical points to exceptional degeneracies.

Findings

Exceptional degeneracies form dynamically in quenched systems.

Observable signatures appear in spectral functions.

Momentum distribution functions reveal non-Hermitian phases.

Abstract

We report on the dynamical formation of exceptional degeneracies in basic correlation functions of non-integrable one- and two-dimensional systems quenched to the vicinity of a critical point. Remarkably, fine-tuned semi-metallic points in the phase diagram of the considered systems are thereby promoted to topologically robust non-Hermitian (NH) nodal phases emerging in the coherent long-time evolution of a dynamically equilibrating system. In the framework of non-equilibrium Green's function methods within the conserving second Born approximation, we predict observable signatures of these novel NH nodal phases in simple spectral functions as well as in the time-evolution of momentum distribution functions.