Chinese Physics B
Quantum Monte Carlo study of hard-core bosons in Creutz ladder with zero flux
Yang Lin, Weichang Hao, Huaiming Guo
Abstract
The quantum phase of hard-core bosons in Creutz ladder with zero flux is studied. For a specific regime of the parameters ( t x = t p , t y < 0), the exact ground-state is found analytically, which is a dimerized insulator with one electron bound in each rung of the ladder. For the case t x , t y , t p > 0, the system is exactly studied using quantum Monte Carlo (QMC) method without a sign problem. It is found that the system is a Mott insulator for small t p and a quantum phase transition to a superfluid phase is driven by increasing t p . The critical t p c is determined precisely by a scaling analysis. Since it is possible that the Creutz ladder is realized experimentally, the theoretical results are interesting to the cold-atom experiments.