Pairing and superfluidity in strongly interacting Fermi gases

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.

Bibliographic Details
Main Author: Schunck, Christian H. (Christian Heinrich)
Other Authors: Wolfgang Ketterle.
Format: Thesis
Language:eng
Published: Massachusetts Institute of Technology 2009
Subjects:
Online Access:http://hdl.handle.net/1721.1/45434
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author Schunck, Christian H. (Christian Heinrich)
author2 Wolfgang Ketterle.
author_facet Wolfgang Ketterle.
Schunck, Christian H. (Christian Heinrich)
author_sort Schunck, Christian H. (Christian Heinrich)
collection MIT
description Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.
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spelling mit-1721.1/454342019-04-12T09:33:30Z Pairing and superfluidity in strongly interacting Fermi gases Schunck, Christian H. (Christian Heinrich) Wolfgang Ketterle. Massachusetts Institute of Technology. Dept. of Physics. Massachusetts Institute of Technology. Dept. of Physics. Physics. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008. Includes bibliographical references (p. 164-173). This thesis describes experiments with superfluid spin mixtures of ultracold fermionic 6Li atoms. The properties of the strongly interacting gas are studied in the crossover regime between Bose-Einstein condensation (BEC) of two-body bound molecules and a Bardeen-Cooper-Schrieffer (BCS) superfluid of pairs bound by many-body interactions. We obtain the homogeneous phase diagram of the two -component gas with resonant interactions. As a function of temperature and spin polarization the phase diagram shows first and second order phase transitions that merge at a tricritical point. At zero temperature a first order phase transition from a superfluid with equal spin populations to a mixed normal phase is observed at a critical spin polarization known as the Chandrasekhar-Clogston limit of superfluidity. Pairing correlations in the superfluid and normal phase are studied with radio-frequency (rf) spectroscopy. A signature of strong correlations is observed above the critical temperature but also at spin polarizations where superfluidity is quenched even at zero temperature. Significant limitations for the interpretation of these experiments due to final state interactions are overcome by the creation of new superfluid spin mixtures. The asymmetric rf dissociation spectra of the new mixture allow us to determine the spectroscopic pair size in the crossover regime. The size of the resonantly interacting pairs is found to be on the order of, but smaller than the interparticle spacing. Rf spectra of the majority component in an imbalanced system show a signature of thermally excited quasiparticles and by comparison to the minority spectra reveal changes in the nature of the binding as a function of spin polarization. by Christian H. Schunck. Ph.D. 2009-04-29T17:41:35Z 2009-04-29T17:41:35Z 2008 2008 Thesis http://hdl.handle.net/1721.1/45434 317888939 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 173 p. application/pdf Massachusetts Institute of Technology
spellingShingle Physics.
Schunck, Christian H. (Christian Heinrich)
Pairing and superfluidity in strongly interacting Fermi gases
title Pairing and superfluidity in strongly interacting Fermi gases
title_full Pairing and superfluidity in strongly interacting Fermi gases
title_fullStr Pairing and superfluidity in strongly interacting Fermi gases
title_full_unstemmed Pairing and superfluidity in strongly interacting Fermi gases
title_short Pairing and superfluidity in strongly interacting Fermi gases
title_sort pairing and superfluidity in strongly interacting fermi gases
topic Physics.
url http://hdl.handle.net/1721.1/45434
work_keys_str_mv AT schunckchristianhchristianheinrich pairingandsuperfluidityinstronglyinteractingfermigases