Quantum Phase Transitions in a Dimerized Bose-Hubbard Model: A DMRG Study

TL;DR

This study uses DMRG to explore the phase diagram of a dimerized Bose-Hubbard model, revealing a new coexistence phase and a novel quantum phase transition, with implications for optical lattice experiments.

Contribution

First DMRG analysis of a dimerized Bose-Hubbard model uncovering a new coexistence phase and quantum phase transition.

Findings

Discovery of a superfluid-bond-wave and Mott insulator-bond wave coexistence phase.

Identification of a new quantum phase transition induced by dimerization.

Proposed experimental realization using optical lattices with different wavelength lasers.

Abstract

We investigate the phase diagram of a dimerized Bose-Hubbard model, using density matrix renormalization group technique. We find a new phase, which is the coexistence of superfluid and bond-wave phases, due to the effect of dimerization. Experimentally dimerization in optical lattice can be realized by using two counter propagating laser beams of different wavelengths. Apart from the conventional superfluid to Mott insulator transition, we find a new quantum phase transition: from superfluid-bond-wave to Mott insulator-bond wave phase. Our study suggests a rich phase diagram which can be easily probed.