Collective Electronic Excitation Coupling between Planar Optical Lattices using Ewald's Method

TL;DR

This paper uses Ewald's summation to analyze collective electronic excitations in parallel optical lattices, revealing how long-range interactions enable exciton coupling and energy transfer between layers, with implications for layered dipolar systems.

Contribution

It introduces an efficient method to calculate exciton dispersion in layered optical lattices considering long-range interactions, highlighting exciton coupling and delocalization effects.

Findings

Exciton dispersion can be efficiently computed for long-range interactions.

Resonant coupling between identical lattices decreases exponentially with distance.

Excitons can delocalize across multiple lattice layers.

Abstract

Using Ewald's summation method we investigate collective electronic excitations (excitons) of ultracold atoms in parallel planar optical lattices including long range interactions. The exciton dispersion relation can then be suitably rewritten and efficiently calculated for long range resonance dipole-dipole interactions. Such in-plane excitons resonantly couple for two identical optical lattices, with an energy transfer strength decreasing exponentially with the distance between the lattices. This allows a restriction of the transfer to neighboring planes and gives rise to excitons delocalized between the lattices. In general equivalent results will hold for any planar system containing lattice layers of optically active and dipolar materials.