Quantum Effects in the Aubry Transition

TL;DR

This paper investigates how quantum tunneling influences the Aubry transition in a system of trapped ions, proposing observable signatures of the quantum transition that could be tested in future experiments.

Contribution

It provides the first detailed analysis of quantum effects on the Aubry transition using Path-Integral Monte Carlo simulations and suggests experimental signatures of the quantum transition.

Findings

Quantum tunneling modifies the phase diagram of the Aubry transition.

New signatures of the quantum Aubry transition are identified.

The proposed signatures are robust against thermal and finite-size effects.

Abstract

The Aubry transition between sliding and pinned phases, driven by the competition between two incommensurate length scales, represents a paradigm that is applicable to a large variety of microscopically distinct systems. Despite previous theoretical studies, it remains an open question to what extent quantum effects modify the transition, or are experimentally observable. An experimental platform that can potentially reach the quantum regime has recently become available in the form of trapped laser-cooled ions subject to a periodic optical potential [A. Bylinskii, D. Gangloff, I. Counts, and V. Vuletic, Nature Materials 15, 717 (2016)]. Using Path-Integral Monte Carlo (PIMC) simulation methods, we analyze the impact of quantum tunneling on the sliding-to-pinned transition in this system, and determine the phase diagram in terms of incommensuration and potential strength. We propose new signatures of the quantum Aubry transition that are robust against thermal and finite-size effects, and that can be observed in future experiments.