A Ground State Monte Carlo Approach for Studies of Dipolar Systems with Rotational Degrees of Freedom

作者：Abolins B P; Zillich R E; Whaley K B^*

来源：Journal of Low Temperature Physics, 2011, 165(5-6): 249-260.

DOI：10.1007/s10909-011-0398-1

• Dipolar molecules
• Monte Carlo

We have developed a path integral ground state Monte Carlo (PIGSMC) algorithm for quantum simulations of rotating dipolar molecules, using a highly accurate sixth-order algorithm. The method allows us to calculate unbiased estimates of ground state properties of dipolar molecules in a variety of geometries, with or without an external electric field. To demonstrate the capability of the approach, we calculate the orientational phase diagram of a one dimensional lattice system of rotating point dipoles in the absence of any external electric fields. We find that for finite lattice size, this system exhibits an order-disorder transition at finite dipolar interaction strength in contrast to the well-known orientational disorder of the corresponding one dimensional O(3) quantum rotor models. Comparison of the quantum Monte Carlo results with a self-consistent field estimate of the phase transition shows the emergence of an ordered phase at non-zero dipolar strength, confirming the symmetry breaking role of the anisotropic dipole-dipole interaction.

• 出版日期2011-12