Many-body localization transition from flatband fine-tuning

TL;DR

This paper demonstrates that by fine-tuning interactions in flatband Hamiltonians, a many-body localization transition can be induced, leading to ergodic or localized phases depending on interaction strength.

Contribution

It introduces a method to induce many-body localization through interaction fine-tuning in flatband systems across various lattice dimensions.

Findings

Evidence of localization transition in spinless fermion models.

Interaction fine-tuning creates local conserved charges and Hilbert space fragmentation.

Transition between ergodic and localized phases observed with varying interaction strength.

Abstract

Translationally invariant flatband Hamiltonians with interactions lead to a many-body localization transition. Our models are obtained from single particle lattices hosting a mix of flat and dispersive bands, and equipped with fine-tuned two--body interactions. Fine-tuning of the interaction results in an extensive set of local conserved charges and a fragmentation of the Hilbert space into irreducible sectors. In each sector, the conserved charges originate from the flatband and act as an effective disorder inducing a transition between ergodic and localized phases upon variation of the interaction strength. Such fine-tuning is possible in arbitrary lattice dimensions and for any many-body statistics. We present computational evidence for this transition with spinless fermions.