Excitons and cavity polaritons for ultracold atoms in an optical lattice

TL;DR

This paper investigates the formation and properties of excitons and cavity polaritons in ultracold atoms within an optical lattice, revealing their spectral features and strong coupling behavior.

Contribution

It introduces a detailed analysis of exciton and polariton dynamics in ultracold atomic lattices, highlighting their spectral signatures and strong coupling phenomena.

Findings

Identification of exciton formation in ultracold atomic lattices.

Observation of cavity polaritons with Rabi splitting.

Spectral signatures in transmission, reflection, and absorption.

Abstract

We study the resonant electronic excitation dynamics for ultracold atoms trapped in a deep optical lattice prepared in a Mott insulator state. Excitons in these artificial crystals are similar to Frenkel excitons in Noble atom or molecular crystals. They appear when the atomic excited state line width is smaller than the exciton band width generated by dipole-dipole coupling. When the atoms are placed within a cavity the electronic excitations and the quantized cavity mode get coupled. In the collective strong coupling regime excitations form two branches of cavity polaritons with Rabi splitting larger than the atomic and the cavity line width. To demonstrate their properties we calculate the transmission, reflection, and absorption spectra for an incident weak probe field, which show resonances at the polariton frequencies.