Disorder-Induced Superfluidity in Hardcore Bosons in Two Dimensions
Abstract
We study the effect of disorder on hardcore bosons in two dimensions at the SU(2) symmetric ``Heisenberg point''. We obtain our results with quantum Monte Carlo simulations using the directed loop algorithm. In the absence of disorder, the system has no long-range order at finite temperature due to the enhanced symmetry. However, the introduction of a disordered potential, uniformly distributed from -D to D, induces a finite-temperature superfluid phase. In particular the diagonal correlation length \xi decreases but the superfluid order-parameter correlation function becomes a power-law. A non-monotonic finite-size behavior is noted and explained as arising due to \xi. We provide evidence that at long distances the effects of a weak disordered potential can be mimicked by an effective uniform potential with a root-mean-square value: mu_eff = D/sqrt{3}. For strong disorder, the system becomes a Bose glass insulator.
Cite
@article{arxiv.cond-mat/0611109,
title = {Disorder-Induced Superfluidity in Hardcore Bosons in Two Dimensions},
author = {Ji-Woo Lee and Shailesh Chandrasekharan and Harold U. Baranger},
journal= {arXiv preprint arXiv:cond-mat/0611109},
year = {2007}
}
Comments
6 pages, 6 figures