Many-body localization of ${\mathbb Z}_3$ Fock parafermions

Abstract

We study the effects of a random magnetic field on a one-dimensional (1D) spin-1 chain with correlated nearest-neigbor XY interaction. We show that this spin model can be exactly mapped onto the 1D disordered tight-binding model of Z3 Fock parafermions (FPFs), exotic anyonic quasiparticles that generalize usual spinless fermions. Thus, we have a peculiar case of a disordered Hamiltonian that, despite being bilinear in the creation and annihilation operators, exhibits a many-body localization (MBL) transition owing to the non-trivial statistics of FPFs. This is in sharp contrast to conventional bosonic and fermionic quadratic disordered Hamiltonians that show single-particle (Anderson) localization. We perform finite-size exact diagonalization calculations of level-spacing statistics, fractal dimensions, and entanglement entropy, and provide convincing evidence for the MBL transition at finite disorder strength.