Disordered impenetrable two-component fermions in one dimension

Abstract

We study the one-dimensional Hubbard model for two-component fermions with infinitely strong on-site repulsion (t − 0 model) in the presence of disorder. The system admits a factorization of charge and spin degrees of freedom, and this allows one to eliminate the spin degrees of freedom for both open and perioidic boundary conditions. Our analytical treatment demonstrates that the type of disorder drastically changes the nature of the emerging phases. The case of spin-independent disorder can be treated as a single-particle problem with Anderson localization. On the contrary, spin-dependent disorder, which can be realized as a random magnetic field, leads to the many-body localization-delocalization transition. Our results provide an extended physical picture of recent numerical findings.

Many-body localization and delocalization dynamics in the thermodynamic limit

“…In this Letter, we study the nature of the MBL regime in two classes of disordered models (see Fig. 1), (i) spin-1/2 two-leg ladders [53,[70][71][72], a quasi-1D system, which represents an intermediate case between a 1D chain and a 2D lattice, and (ii) Fermi-Hubbard (FH) chains [73][74][75][76][77][78][79], where disorder only couples to the charge degrees of freedom. Both can also be viewed as 1D models with local Hilbert-space dimension greater than two.…”