Laser induced $\mathcal{PT}$-symmetry breaking in the fluctuations of electronic fluids

TL;DR

This paper investigates how laser pulses can control non-Hermitian degeneracies, known as exceptional points, in electronic fluids, leading to a $ extit{PT}$-symmetry breaking phase transition with unique spectral features.

Contribution

It demonstrates the ability to manipulate collective mode spectra and induce a third-order exceptional point in electronic fluids using laser control.

Findings

Laser pulses can tune non-Hermitian degeneracies in electronic fluids.

A $ extit{PT}$-symmetry breaking transition with exceptional points is achieved.

The transition features a cubic root gap closing, indicating a third-order exceptional point.

Abstract

Electronic fluids can display exciting dynamical properties. In particular, due to Landau damping, the collective modes spectrum of an electronic system with multipolar interactions is non-hermitian, and can present non-hermitian degeneracies called $\textit{exceptional points}$. In this work, we want to explore the dynamical properties of these degeneracies using laser control. We show that by using a light pulse, we can control the collective mode spectrum and tune a non-hermitian $\mathcal{PT}$ phase transition in which two exceptional points anhilate each other. At this transition, the gap closes with a cubic root signature, what defines a third order exceptional point.