Interaction-enhanced many-body localization in a 1D quasiperiodic model with long-range hopping

TL;DR

This paper investigates a 1D quasiperiodic model with long-range hopping, revealing an interaction-enhanced many-body localization phenomenon where moderate interactions induce localization due to the fragility of certain spectral bands.

Contribution

It introduces the concept of interaction-enhanced MBL in a solvable model, explaining it through a mean-field theory and quasihole physics, which is a novel insight into localization mechanisms.

Findings

Interaction enhances localization in the model.

Fragile spectral bands are stabilized by interactions.

Mean-field theory accurately predicts highly excited states.

Abstract

We study the many-body localization (MBL) transition in an 1D exactly solvable system with long-range hopping and quasiperiodic on-site potential introduced in Phys. Rev. Lett. 131, 186303 (2023). Unlike other disorder or quasiperiodic model, an interaction-enhanced MBL happens in the moderate interaction regime, which is dubbed as the interaction-enhanced MBL. This counterintuitive phenomenon can be understood by noticing the fragility of the critical band lying at the bottom of the spectrum. The fragile band is localized by other localized states once the interaction is turned on. This mechanism can be verified by introducing a mean-field theory description which can derive highly excited states with high accuracy. The effectiveness of this mean-field theory is captured by the quasihole physics, validated by the particle entanglement spectra.