Two-Stage Melting in Systems of Strongly Interacting Rydberg Atoms

TL;DR

This paper investigates the phase transitions in a one-dimensional lattice of strongly interacting Rydberg atoms, revealing a two-stage melting process from classical solid structures to a paramagnetic state.

Contribution

It introduces a detailed analysis of the ground state phases and phase transitions in Rydberg atom systems, including the discovery of a two-stage melting process.

Findings

Complete devil's staircase in classical limit

Transition to a floating solid with algebraic correlations

Melting into a paramagnetic ground state

Abstract

We analyze the ground state properties of a one-dimensional cold atomic system in a lattice, where Rydberg excitations are created by an external laser drive. In the classical limit, the ground state is characterized by a complete devil's staircase for the commensurate solid structures of Rydberg excitations. Using perturbation theory and a mapping onto an effective low energy Hamiltonian, we find a transition of these commensurate solids into a floating solid with algebraic correlations. For stronger quantum fluctuations the floating solid eventually melts within a second quantum phase transition and the ground state becomes paramagnetic.