Document Type

Project

Publication Date

Spring 6-2017

Keywords

Theoretical physics

Abstract

We investigate the ground state and low-lying excitations of a Bose-Einstein condensate (BEC) of dipolar molecules interacting via short-range contact and long-range dipole­ dipole interactions (ddi). We find the mean field ground state via the variational principle using a separable bosonic wave function as the variational state. This state can be refined to include small excitations in the form of plane waves, and the results of the variational calculation are a set of dispersion relations for the low-lying excitations. We analyze the polarization and stability of the ground state as a function of the strength of the external polarizing electric field, the strength of the ddi, and the strength of the contact interactions. In a certain parameter regime of strong contact interactions that oppose the dipole -dipole interactions, we identify a possible signature of a first -order phase transition: the polarization of the gas discontinuously flips as the electric field is continuously ramped through zero field. By examining the dispersion relations, we find that the ground state in this parameter regime is unstable.

Department

Physics/Astronomy

Subjects - Topical (LCSH)

Bose-Einstein condensation; Path integrals; Polarizability (Electricity); Bose-Einstein gas

Genre/Form

student projects; term papers

Type

Text

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.

Rights Statement

http://rightsstatements.org/vocab/InC/1.0/

Language

English

Format

application/pdf

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Included in

Physics Commons

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