Mott glass from localization and confinement

TL;DR

This paper investigates a one-dimensional fermionic system with confining interactions and disorder, revealing a unique Mott-glass phase characterized by incompressibility and gapless optical conductivity, distinct from known insulating states.

Contribution

It introduces the concept of a Mott-glass state arising from the interplay of disorder and confinement, analyzed through bosonization and variational methods.

Findings

System is incompressible with gapless optical conductivity.

Identifies a distinct Mott-glass phase due to disorder and confinement.

Phenomenology likely persists at non-zero temperatures.

Abstract

We study a system of fermions in one spatial dimension with linearly confining interactions and short-range disorder. We focus on the zero temperature properties of this system, which we characterize using bosonization and the Gaussian variational method. We compute the static compressibility and ac conductivity, and thereby demonstrate that the system is incompressible, but exhibits gapless optical conductivity. This corresponds to a "Mott-glass" state, distinct from an Anderson and a fully gapped Mott insulator, arising due to the interplay of disorder and charge confinement. We argue that this "Mott-glass" phenomenology should persist to non-zero temperatures.