Issue
EPL
Volume 85, Number 4, February 2009
Article Number 43001
Number of page(s) 5
Section Atomic, Molecular and Optical Physics
DOI http://dx.doi.org/10.1209/0295-5075/85/43001
Published online 18 February 2009
EPL, 85 (2009) 43001
DOI: 10.1209/0295-5075/85/43001

Quantum phase transitions in a dimerized Bose-Hubbard model: A DMRG study

Anasuya Kundu and Swapan K. Pati

Theoretical Sciences Unit and DST Unit on Nanoscience, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur Campus - Bangalore 560064, India

pati@jncasr.ac.in

received 14 October 2008; accepted in final form 26 January 2009; published February 2009
published online 18 February 2009

Abstract
We investigate the phase diagram of a dimerized Bose-Hubbard model, using a 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 counterpropagating laser beams of different wavelengths. Apart from the conventional superfluid$\hbox{--} $to$\hbox{--} $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.

PACS
37.10.Jk - Atoms in optical lattices.
05.30.Jp - Boson systems.

© EPLA 2009