Bosonic Condensation and Disorder-Induced Localization in a Flat Band

TL;DR

This paper demonstrates bosonic condensation in a flat band of a micro-pillar optical cavity lattice, revealing how disorder induces localization and offering new insights into light-matter coherence under frustration and dissipation.

Contribution

It introduces a method to engineer flat bands in optical lattices and observes bosonic condensation into these bands, highlighting disorder-induced localization effects.

Findings

Bosonic condensation occurs in the engineered flat band.

Disorder causes the condensate to fragment into localized modes.

The system provides a platform to study coherence under frustration and dissipation.

Abstract

We report on the engineering of a non-dispersive (flat) energy band in a geometrically frustrated lattice of micro-pillar optical cavities. By taking advantage of the non-hermitian nature of our system, we achieve bosonic condensation of exciton-polaritons into the flat band. Due to the infinite effective mass in such band, the condensate is highly sensitive to disorder and fragments into localized modes reflecting the elementary eigenstates produced by geometric frustration. This realization offers a novel approach to studying coherent phases of light and matter under the controlled interplay of frustration, interactions and dissipation.