Emergent dimerization and localization in disordered quantum chains

TL;DR

This paper reveals a new nonperturbative mechanism where strong interactions and aperiodic disorder induce a gapped, dimerized phase in quantum chains, expanding understanding of disorder effects in many-body systems.

Contribution

It introduces a novel mechanism for gap formation in strongly interacting disordered quantum chains, demonstrated in the antiferromagnetic XXZ model, with characterization of the phase transition.

Findings

Emergence of a dimerized, gapped phase due to combined strong interactions and disorder.

The mechanism is general for strongly modulated quasiperiodic disorder.

Characterization of the quantum phase transition with critical exponents.

Abstract

We uncover a novel mechanism for inducing a gapful phase in interacting many-body quantum chains. The mechanism is nonperturbative, being triggered only in the presence of both strong interactions and strong aperiodic (disordered) modulation. In the context of the critical antiferromagnetic spin-1/2 XXZ chain, we identify an emerging dimerization which removes the system from criticality and stabilizes the novel phase. This mechanism is shown to be quite general in strongly interacting quantum chains in the presence of strongly modulated quasiperiodic disorder which is, surprisingly, perturbatively irrelevant. Finally, we also characterize the associated quantum phase transition via the corresponding critical exponents and thermodynamic properties.