Exciton-Polariton scattering for defect detection in cold atom Optical Lattices

TL;DR

This paper investigates how defects in ultracold atom optical lattices influence exciton and polariton dynamics, proposing cavity polaritons as a tool for defect detection and control via scattering manipulation.

Contribution

It introduces a novel method using cavity polaritons to detect and control defects in optical lattices through exciton-polariton scattering.

Findings

Vacancies act as hard sphere scatterers for excitons.

Singly occupied sites can create attractive or repulsive scattering potentials.

Scattering potential can be tuned by exciton-photon detuning and photon polarization.

Abstract

We study the effect of defects in the Mott insulator phase of ultracold atoms in an optical lattice on the dynamics of resonant excitations. Defects, which can either be empty sites in a Mott insulator state with one atom per site or a singly occupied site for a filling factor two, change the dynamics of Frenkel excitons and cavity polaritons. While the vacancies in first case behave like hard sphere scatters for excitons, singly occupied sites in the latter case can lead to attractive or repulsive scattering potentials. We suggest cavity polaritons as observation tool of such defects, and show how the scattering can be controlled in changing the exciton-photon detuning. In the case of asymmetric optical lattice sites we present how the scattering effective potential can be detuned by the cavity photon polarization direction, with the possibility of a crossover from a repulsive into an attractive potential.