Many-body localization transition from flatband fine-tuning

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.

Heat percolation in many-body flatband localizing systems

“…Flatband networks are increasingly permeating the quantum many-body field. Indeed, single-particle CLS have been extended to many-body CLS [29][30][31], while quantum scars [32][33][34] and MBL-like dynamics [35][36][37] have been reported very recently in flatband lattices. But more importantly, it has been shown that fine-tuning of the interaction in ABF networks induces an extensive set of local constraints which completely suppress charge transport in any spatial dimension -a phenomenon called many-body flatband localization (MBFBL) [38][39][40].…”

“…These results and open quests emphasize MBFBL networks as experimentally realizable [64][65][66] valid platforms to explore novel phenomena in quantum systems -highlighting jointly with Refs. [29][30][31][32][33][34][35][36][37][38][39][40] the progressively growing relevance of flatbands in the realm of many-body physics.…”