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Title:Transport and disorder-induced localization of ultracold Fermi gases
Author(s):McGehee, William R
Director of Research:DeMarco, Brian L.
Doctoral Committee Chair(s):Mason, Nadya
Doctoral Committee Member(s):Gadway, Bryce; Clark, Bryan
Department / Program:Physics
Discipline:Physics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Anderson Localization
Many-Body Localization
Optical Speckle
Optical Lattice
Ultracold Atoms
Disordered Transport
Strongly-Interacting Materials
Hubbard Model
Fermi-Hubbard Model
Fermi Gas
Abstract:We experimentally study localization and dynamics of ultracold fermions in speckle and optical lattice potentials to explore Anderson localization, many-body localization, and relaxation dynamics in strongly correlated systems. Anderson localization is probed by releasing non-interacting, spin-polarized gases into three dimensional, anisotropic disordered potentials produced from optical speckle. A fraction of the atoms are localized by the disorder, and a mobility edge is found separating localized from extended states. The length scale of the speckle is varied, and the localized state is found to scale linearly with the geometric mean of the speckle autocorrelation length. We realize the Fermi Hubbard model by loading atoms in a cubic optical lattice. Non-equilibrium momentum distributions are created via Raman transitions, and the excitation relaxation rate is measured in the lattice. Transport experiments were performed in a disordered optical lattice to explore the disordered Hubbard model. These experiments reveal localization in the presence of strong interactions and an interaction driven metal-to-insulator transition. The localized state is found to be insensitive to a doubling in the temperature of the gas and is consistent with predictions of many-body localization.
Issue Date:2015-07-14
Type:Thesis
URI:http://hdl.handle.net/2142/88039
Rights Information:Copyright 2015 William Russell McGehee
Date Available in IDEALS:2015-09-29
Date Deposited:August 201


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