Transport and disorder-induced localization of ultracold Fermi gases

McGehee, William R

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https://hdl.handle.net/2142/88039 Copy

Description

Title

Transport and disorder-induced localization of ultracold Fermi gases

Author(s)

McGehee, William R

Issue Date

2015-07-14

Director of Research (if dissertation) or Advisor (if thesis)

DeMarco, Brian L.

Doctoral Committee Chair(s)

Mason, Nadya

Committee Member(s)

• Gadway, Bryce
• Clark, Bryan

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(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.

Graduation Semester

2015-8

Type of Resource

text

Permalink

http://hdl.handle.net/2142/88039

Copyright and License Information

Copyright 2015 William Russell McGehee

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