Lifetime of flatband states

TL;DR

This paper investigates the finite lifetime of flatband states in quantum systems, revealing that disorder causes a delayed decay through dephasing, which limits their reliable storage capacity.

Contribution

It introduces a disorder-induced decay mechanism for flatband states, analyzed via quantum master equations, applicable across various platforms.

Findings

Disorder causes a delayed, dephasing-mediated decay of flatband states.

Detuning from band intersections suppresses direct decay into dispersive bands.

The decay mechanism is demonstrated in the cross-stitch lattice model.

Abstract

Flatbands feature the distortion-free storage of compact localized states of tailorable shape. Their reliable storage sojourn is, however, limited by disorder potentials, which generically cause uncontrolled coupling into dispersive bands. We find that, while detuning flatband states from band intersections suppresses their direct decay into dispersive bands, disorder-induced state distortion causes a delayed, dephasing-mediated decay, lifting the static nature of flatband states and setting a finite lifetime for the reliable storage sojourn. We exemplify this generic, disorder-induced decay mechanism at the cross-stitch lattice. Our analysis, which applies platform-independently, relies on the time-resolved treatment of disorder-averaged quantum systems with quantum master equations.