Non-Hermitian synthetic lattices with light-matter coupling

TL;DR

This paper introduces a method to create synthetic lattices using light-matter coupling in exciton-photon chains, revealing phase transitions and exceptional points in non-Hermitian systems, with implications for higher-dimensional studies.

Contribution

It demonstrates how tuning light-matter coupling in a synthetic lattice induces phase transitions and exceptional points, advancing the understanding of non-Hermitian photonic systems.

Findings

Flat band to dispersive band transition controlled by coupling

Enhanced robustness of flat band in non-Hermitian systems

Potential for exploring higher-dimensional non-Hermitian phases

Abstract

We propose that light-matter coupling can be used to realize synthetic lattices. In particular, we consider a one-dimensional chain of exciton-photon sites to create a comb lattice that exhibits a transition from a flat band to a finite mass dispersion by tuning site-dependent light-matter coupling. Moreover, in a non-Hermitian system with gain and loss, the flat band phase is much more robust and the transition is accompanied by the appearance of exceptional points in the complex energy spectrum. We demonstrate that by engineering the light-matter coupling in the synthetic lattice, one can explore various phases in the lasing regime. Our proposal paves the way for studying non-Hermitian systems in higher dimensions.