We study the supercounterfluid (SCF) states in the two-component hard-core Bose-Hubbard model on a square lattice, using the quantum Monte Carlo method based on the worm (directed-loop) algorithm. Since the SCF state is a state of a pair condensation characterized by a†b ≠ 0,a=0, and b=0, where a and b are the order parameters of the two components, it is important to study behaviors of the pair-correlation function a ibi†aj†bj. For this purpose, we propose a choice of the worm head for calculating the pair-correlation function. From this pair correlation, we confirm the Kosterlitz-Thouless character of the SCF phase. The simulation efficiency is also improved in the SCF phase.
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 2011 Feb 28|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics