Efimov States of Strongly Interacting Photons

TL;DR

This paper demonstrates the emergence of Efimov states in strongly interacting photons within Rydberg atomic gases, revealing universal three-body physics and conditions for experimental observation.

Contribution

It introduces the realization of Efimov physics with photons, showing how effective interactions lead to observable Efimov states in a new quantum optical system.

Findings

Efimov states can form with photons in Rydberg gases.

Three-body loss can be suppressed, enabling observation.

Conditions for experimental detection are identified.

Abstract

We demonstrate the emergence of universal Efimov physics for interacting photons in cold gases of Rydberg atoms. We consider the behavior of three photons injected into the gas in their propagating frame, where a paraxial approximation allows us to consider them as massive particles. In contrast to atoms and nuclei, the photons have a large anisotropy between their longitudinal mass, arising from dispersion, and their transverse mass, arising from diffraction. Nevertheless, we show that in suitably rescaled coordinates the effective interactions become dominated by s-wave scattering near threshold and, as a result, give rise to an Efimov effect near unitarity. We show that the three-body loss of these Efimov trimers can be strongly suppressed and determine conditions under which these states are observable in current experiments. These effects can be naturally extended to probe few-body universality beyond three bodies, as well as the role of Efimov physics in the non-equilbrium, many-body regime.