Theoretical Studies of Ultracold Dipolar Molecules

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منو

" Theoretical Studies of Ultracold Dipolar Molecules "
Abolins, Brendan Patrick Whaley, K. Birgitta

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	898534
Doc. No	:	TL7b41s0g1
Main Entry	:	Jones, Kyle Burke
Title & Author	:	Theoretical Studies of Ultracold Dipolar Molecules\ Abolins, Brendan PatrickWhaley, K. Birgitta
Date	:	2014
student score	:	2014
Abstract	:	Strongly interacting ultracold dipolar molecules are a rich platform for quantum information and quantum simulation of phenomena relevant to condensed matter systems. This dissertation presents novel theoretical and computational studies of ultracold dipolar molecules relevant to these areas in three broad categories. First, the path integral ground state quantum Monte Carlo method is extended to simulations with both translational and rotational degrees of freedom, including the development of a novel estimator of the elementary excitation energies of a system with these degrees of freedom based on the well known Feynman-Bijl approximation. This is then used to study dipolar molecular ensembles confined to one-dimensional optical lattices. The ground state phase diagram is characterized with both a mean-field method and the aforementioned quantum Monte Carlo method. A quantum phase transition is found for very short optical lattice spacings or very large dipole moments. The prospects for experimentally realizing a system which exhibits this phase transition are discussed. Second, the path integral ground state quantum Monte Carlo method is utilized to study the ground state of dipole molecules confined to two-dimensional optical lattices. On square lattices a crossover from a weakly interacting disordered phase to a strongly interacting striped phase is found for short lattice spacings or large dipole moments. On triangular lattices a crossover between a disordered phase and a completely polarized phase is found, also for short lattice spacings or large dipole moments. The relevance of such simulations to self-assembled dipolar crystals in two dimensions is discussed and simulation results of these systems are presented. Simulations of polarized and harmonically confined molecular systems in two dimensions with translations and rotations are also presented and a realistic interaction potential using highly accurate ab initio quantum chemistry techniques is calculated for LiH--LiH interactions as a preliminary step toward developing a high quality trial wave function for the simulation of systems possessing both translational and rotational degrees of freedom. Finally, several novel applications for dipolar molecules confined to optical lattices are proposed. An experimental realization of a topological phase using
Added Entry	:	Abolins, Brendan Patrick
Added Entry	:	UC Berkeley