A continuum path integral approach to the simulation of a unitary gas

This thesis presents an investigation by simulation of a unpolarized fermionic unitary gas system composed of two interacting fermionic species. While these species do not interact amongst themselves, they interact with each other using a pairwise zero-range delta function potential that has been tuned to unitarity i.e.the scattering length a_s=-\infty. A path integral Monte Carlo simulation of such a system is performed using an exact novel zero-range, delta function pair propagator which has been tuned to the unitary limit so that essentially all interactions amongst the interacting particles are comprised of s-wave interactions. This tuning in some sense yields the simplest imaginable interacting fermionic system which out to display features that would apply universally to interacting fermionic particles with particular interest within this field of study being in understanding the unitary BCS-BEC crossover. Numerical and ergodic challenges to sampling a divergent approximate path integral are discussed and solutions are proposed, implemented and explored. This thesis represents a step closer to this understanding by investigating this system with this novel propagator in a fixed-node path integral Monte Carlo framework and comparing to earlier work.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemical Physics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Knapp, Adam Christopher

Contributors dc:contributor

• Ceperley, David M.
• Clark, Bryan K
• Gruebele, Martin
• Phillips, Philip W.

• Unitary Fermi Gas
• Computational Simulation of Cold Atoms

Statement dc:rights

• Copyright 2015 Adam Christopher Knapp

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/88132

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/88132