Two-polariton bound states in the Jaynes-Cummings-Hubbard model

TL;DR

This paper investigates the formation of two-polariton bound states in the one-dimensional Jaynes-Cummings-Hubbard model, revealing conditions under which strong correlations and spatial confinement occur.

Contribution

It identifies the critical ratio of vacuum Rabi frequency to tunneling rate necessary for bound state emergence and characterizes their properties in the model.

Findings

Bound states form when the ratio exceeds a critical value.

Bound states exhibit strong spatial correlation.

Critical ratio depends on quasi-momentum quantum number.

Abstract

We examine the eigenstates of the one-dimensional Jaynes-Cummings-Hubbard (JCH) model in the two-excitation subspace. We discover that two-excitation bound states emerge when the ratio of vacuum Rabi frequency to the tunneling rate between cavities exceeds a critical value. We determine the critical ratio as a function of the quasi-momentum quantum number, and indicate that the bound states carry a strong correlation in which the two polaritons appear to be spatially confined together.