# Exploring non-equilibrium phases of the generalized Dicke model with a trapped Rydberg ion quantum simulator

## TL;DR

This paper explores how Rydberg states in trapped ion systems enable the study of non-equilibrium phases in the generalized Dicke model, revealing new dynamical behaviors and detection methods.

## Contribution

It demonstrates the potential of Rydberg ion platforms to access and classify non-equilibrium phases in the generalized Dicke model with controllable interactions.

## Key findings

- Identification of multi-phase coexistence regions
- Detection of phonon-lasing regimes via fluorescence signals
- Altered collective behavior due to dipolar Rydberg interactions

## Abstract

Trapped ions are a versatile platform for the investigation of quantum many-body phenomena, in particular for the study of scenarios where long-range interactions are mediated by phonons. Recent experiments have shown that the trapped ion platform can be augmented by exciting high-lying Rydberg states. This introduces controllable state-dependent interactions that are independent from the phonon structure. However, the many-body physics in this newly accessible regime is largely unexplored. We show that this system grants access to generalized Dicke model physics, where dipolar interactions between ions in Rydberg states drastically alter the collective non-equilibrium behavior. We analyze and classify the emerging dynamical phases and identify a host of non-equilibrium signatures such as multi-phase coexistence regions and phonon-lasing regimes. We moreover show how they can be detected and characterized through the fluorescence signal of scattered photons. Our study thus highlights new capabilities of trapped Rydberg ion systems for creating and detecting quantum non-equilibrium phases.