Density matrix renormalization group for disordered bosons in one dimension

TL;DR

This paper uses the density matrix renormalization group to map out the phase diagram of disordered bosons in one dimension, revealing the interplay of superfluid, Mott insulator, and Bose glass phases with reentrant behavior.

Contribution

It provides a detailed zero-temperature phase diagram of the disordered Bose-Hubbard model in one dimension, highlighting the reentrant Bose glass phase and superfluid behavior.

Findings

Mott insulator always separated from superfluid by Bose glass at integer filling

Reentrant Bose glass phase as a function of interaction and disorder

Superfluid density peaks at balanced kinetic and repulsive energies at half-filling

Abstract

We calculate the zero-temperature phase diagram of the disordered Bose-Hubbard model in one dimension using the density matrix renormalization group. For integer filling the Mott insulator is always separated from the superfluid by a Bose glass phase. There is a reentrance of the Bose glass both as a function of the repulsive interaction and of disorder. At half-filling where no Mott insulator exists, the superfluid density has a maximum where the kinetic and repulsive energies are about the same. Superfluidity is suppressed both for small and very strong repulsion but is always monotonic in disorder.