Resonant atom-field interaction in large-size coupled-cavity arrays

TL;DR

This paper demonstrates that staggered inter-cavity couplings in large coupled-cavity arrays enable resonant atom-field interactions and energy exchange, contrasting with uniform arrays where atomic dynamics are frozen, and highlights potential for experimental observation.

Contribution

It reveals that staggered hopping rates induce resonant atom-field dynamics in large arrays, a phenomenon absent in uniform arrays, due to the emergence of an energy gap and a bound mode.

Findings

Resonant energy exchange occurs in staggered arrays even in the thermodynamic limit.

Atomic dynamics can be frozen or active depending on the cavity excitation.

The phenomena are observable in small-size arrays, facilitating experimental verification.

Abstract

We consider an array of coupled cavities with staggered inter-cavity couplings, where each cavity mode interacts with an atom. In contrast to large-size arrays with uniform-hopping rates where the atomic dynamics is known to be frozen in the strong-hopping regime, we show that resonant atom-field dynamics with significant energy exchange can occur in the case of staggered hopping rates even in the thermodynamic limit. This effect arises from the joint emergence of an energy gap in the free photonic dispersion relation and a discrete frequency at the gap's center. The latter corresponds to a bound normal mode stemming solely from the finiteness of the array length. Depending on which cavity is excited, either the atomic dynamics is frozen or a Jaynes-Cummings-like energy exchange is triggered between the bound photonic mode and its atomic analogue. As these phenomena are effective with any number of cavities, they are prone to be experimentally observed even in small-size arrays.