Thermodynamics and solitonic excitations of a strongly-interacting Fermi gas
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2015.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2015
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| Online Access: | http://hdl.handle.net/1721.1/99309 |
| _version_ | 1811095165656367104 |
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| author | Ku, Mark Jen-Hao |
| author2 | Martin W. Zwierlein. |
| author_facet | Martin W. Zwierlein. Ku, Mark Jen-Hao |
| author_sort | Ku, Mark Jen-Hao |
| collection | MIT |
| description | Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2015. |
| first_indexed | 2024-09-23T16:11:42Z |
| format | Thesis |
| id | mit-1721.1/99309 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T16:11:42Z |
| publishDate | 2015 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/993092019-04-10T09:31:40Z Thermodynamics and solitonic excitations of a strongly-interacting Fermi gas Ku, Mark Jen-Hao Martin W. Zwierlein. Massachusetts Institute of Technology. Department of Physics. Massachusetts Institute of Technology. Department of Physics. Physics. Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2015. Cataloged from PDF version of thesis. Includes bibliographical references (pages 241-259). In this thesis, I present experiments that study the thermodynamics and solitonic excitations of a strongly-interacting Fermi gas, realized with 6Li atoms at a Feshbach resonance where the scattering length is large. The strongly-interacting Fermi gas, also called the unitary Fermi gas, exhibits a novel superfluidity that is a crossover of the Bose-Einstein condensation of molecules and Bardeen-Cooper-Schrieffer superfluid of long-ranged Cooper pairs, with a high critical temperature and a small healing length. The unitary Fermi gas serves as a model for other strongly correlated fermions, such dilute neutron matter in the crust of neutron stars. The homogeneous equation of state of a unitary Fermi gas was measured with high precision via a method that requires no theoretical input nor external thermometer. The measurement provides an accurate value of the critical temperature and the Bertsch parameter that characterizes the ground state energy. The equation of state is then used to provide a prediction for the higher collective modes. I also describe a method to obtain the equation of state of global thermodynamic quantitites of harmonically trapped gases from their column density. In another set of experiments, long-lived solitonic excitation was generated via a one-sided phase imprinting. The excitation's slow oscillation within the trapped superfluid indicates a large ratio of the inertial mass to the gravitational mass. Tomographic imaging identifies the excitation to be a solitonic vortex. The precession period in the BEC-BCS crossover was measured, and good agreement is found with predictions from a hydrodynamic model. Prior to the formation of the vortex, the evolution of the superfluid after the phase imprint was investigated. A dark planar soliton was observed to emerge after the phase imprint, undergo snake instability, subsequently decay into a ring defect, and eventually convert into a single vortex. The growth rate of the transverse modes during the snake instability was measured. by Mark Jen-Hao Ku. Ph. D. 2015-10-14T15:04:51Z 2015-10-14T15:04:51Z 2015 2015 Thesis http://hdl.handle.net/1721.1/99309 922937606 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 259 pages application/pdf Massachusetts Institute of Technology |
| spellingShingle | Physics. Ku, Mark Jen-Hao Thermodynamics and solitonic excitations of a strongly-interacting Fermi gas |
| title | Thermodynamics and solitonic excitations of a strongly-interacting Fermi gas |
| title_full | Thermodynamics and solitonic excitations of a strongly-interacting Fermi gas |
| title_fullStr | Thermodynamics and solitonic excitations of a strongly-interacting Fermi gas |
| title_full_unstemmed | Thermodynamics and solitonic excitations of a strongly-interacting Fermi gas |
| title_short | Thermodynamics and solitonic excitations of a strongly-interacting Fermi gas |
| title_sort | thermodynamics and solitonic excitations of a strongly interacting fermi gas |
| topic | Physics. |
| url | http://hdl.handle.net/1721.1/99309 |
| work_keys_str_mv | AT kumarkjenhao thermodynamicsandsolitonicexcitationsofastronglyinteractingfermigas |