Enhanced many-body localization in a kinetically constrained model

TL;DR

This paper demonstrates that kinetic constraints in a model of interacting hardcore bosons significantly enhance many-body localization, leading to a finite-size transition at lower disorder strengths and affecting thermalization dynamics.

Contribution

It reveals that kinetic constraints promote localization in many-body systems, resulting in a lower disorder threshold for localization compared to unconstrained models.

Findings

Disorder induces long-lived localized dynamics.

Kinetic constraints lower the disorder threshold for MBL.

Eigenstates show increased localization due to constraints.

Abstract

In the study of the thermalization of closed quantum systems, the role of kinetic constraints on the temporal dynamics and the eventual thermalization is attracting significant interest. Kinetic constraints typically lead to long-lived metastable states depending on initial conditions. We consider a model of interacting hardcore bosons with an additional kinetic constraint that was originally devised to capture glassy dynamics at high densities. As a main result, we demonstrate that the system is highly prone to localization in the presence of uncorrelated disorder. Adding disorder quickly triggers long-lived dynamics as evidenced in the time evolution of density autocorrelations. Moreover, the kinetic constraint favors localization also in the eigenstates, where a finite-size transition to a many-body localized phase occurs for much lower disorder strengths than for the same model without a kinetic constraint. Our work sheds light on the intricate interplay of kinetic constraints and localization and may provide additional control over many-body localized phases in the time domain.