Interplay of Quantum and Thermal Fluctuations in Two-Dimensional Randomly Pinned Charge Density Waves

TL;DR

This paper investigates how quantum and thermal fluctuations interact in two-dimensional charge density waves with disorder, revealing a crossover in fluctuation dynamics using a non-perturbative large-N approach.

Contribution

It introduces a quantum extension of an exactly solvable classical model, providing a comprehensive phase diagram and analyzing fluctuation dynamics in disordered charge density waves.

Findings

Identifies a crossover between under-damped and over-damped fluctuation regimes.

Provides a non-perturbative phase diagram including quantum and thermal effects.

Highlights the importance of disorder in the stability of charge density wave order.

Abstract

The interplay between quantum and thermal fluctuations in the presence of quenched random disorder is a long-standing open theoretical problem which has been made more urgent by advances in modern experimental techniques. The fragility of charge density wave order to impurities makes this problem of particular interest in understanding a host of real materials, including the cuprate high-temperature superconductors. To address this question, we consider the quantum version of an exactly solvable classical model of two-dimensional randomly pinned incommensurate charge density waves first introduced by us in a recent work, and use the large-$N$ technique to obtain the phase diagram and order parameter correlations. Our theory considers quantum and thermal fluctuations and disorder on equal footing by accounting for all effects non-perturbatively, which reveals a novel crossover between under-damped and over-damped dynamics of the fluctuations of the charge density wave order parameter.