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Resonant and nonresonant interaction...

Wachter, Jochen.

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Resonant and nonresonant interactions in cold quantum gases.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Resonant and nonresonant interactions in cold quantum gases./
Author:	Wachter, Jochen.
Description:	170 p.
Notes:	Adviser: Murray Holland.
Contained By:	Dissertation Abstracts International68-11B.
Subject:	Physics, Atomic. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3284438
ISBN:	9780549314912

Resonant and nonresonant interactions in cold quantum gases.
Wachter, Jochen.

Resonant and nonresonant interactions in cold quantum gases. - 170 p.

Adviser: Murray Holland.

Thesis (Ph.D.)--University of Colorado at Boulder, 2007.

In the first part of this thesis, we present a unified kinetic theory that describes the finite-temperature, non-equilibrium dynamics of a Bose-Einstein condensed gas interacting with a thermal cloud in a trap. This theory includes binary interactions to second order in the interaction potential and reduces to a diagonal quantum Boltzmann equation for Bogoliubov quasiparticles. The Hartree-Fock-Bogoliubov interactions include the pairing field and are expressed as many-body T matrices to second order. The interactions thus include the correct renormalized scattering physics. This renormalized theory is automatically gapless. Thus, the excited Bogoliubov modes are naturally orthogonal to the condensate ground state. This kinetic theory is a complete second-order theory that reduces to the Gross-Pitaevskii equation and the quantum Boltzmann equation in the respective limits and thus is capable of describing the system over a wide temperature range.

ISBN: 9780549314912Subjects--Topical Terms:

1029235
Physics, Atomic.

Resonant and nonresonant interactions in cold quantum gases.
LDR:03377nam 2200349 a 45 001 942167
005 20110519
008 110519s2007 ||||||||||||||||| ||eng d
020 $a 9780549314912
035 $a (UMI)AAI3284438
035 $a AAI3284438
040 $a UMI $c UMI
100 1 $a Wachter, Jochen. $3 1266263
245 1 0 $a Resonant and nonresonant interactions in cold quantum gases.
300 $a 170 p.
500 $a Adviser: Murray Holland.
500 $a Source: Dissertation Abstracts International, Volume: 68-11, Section: B, page: 7389.
502 $a Thesis (Ph.D.)--University of Colorado at Boulder, 2007.
520 $a In the first part of this thesis, we present a unified kinetic theory that describes the finite-temperature, non-equilibrium dynamics of a Bose-Einstein condensed gas interacting with a thermal cloud in a trap. This theory includes binary interactions to second order in the interaction potential and reduces to a diagonal quantum Boltzmann equation for Bogoliubov quasiparticles. The Hartree-Fock-Bogoliubov interactions include the pairing field and are expressed as many-body T matrices to second order. The interactions thus include the correct renormalized scattering physics. This renormalized theory is automatically gapless. Thus, the excited Bogoliubov modes are naturally orthogonal to the condensate ground state. This kinetic theory is a complete second-order theory that reduces to the Gross-Pitaevskii equation and the quantum Boltzmann equation in the respective limits and thus is capable of describing the system over a wide temperature range.
520 $a In the second part, we consider a many-body theory of a dilute Fermi gas near a Feshbach resonance. Experiments explore the crossover physics between the Bardeen-Cooper-Schrieffer (BCS) superfluidity of a two-spin Fermi gas, and the Bose-Einstein condensation (BEC) of composite bosons. We consider correlations between a composite boson and a fermion pair and show that such correlations are the minimal ingredients needed in a many-body theory to generate the correct boson-boson scattering length in the Bose-Einstein limit of the crossover.
520 $a We also use imaginary-time propagation to find zero-temperature ground states in the BCS/BEC crossover. A cumulant expansion allows us to systematically include higher-order interactions between bosons and fermions. In particular, we calculate the Hartree term across the resonance. We further apply the cumulant-expansion method to thermal fermions and composite bosons interacting above the transition temperature in the normal phase. We numerically calculate the full time dependence in ramps across the resonance in this regime and find different two-body and many-body time scales in the system. We calculate molecular conversion efficiencies as a function of temperature and phase-space density, and find good agreement with results from JILA potassium experiments.
590 $a School code: 0051.
650 4 $a Physics, Atomic. $3 1029235
650 4 $a Physics, Theory. $3 1019422
690 $a 0748
690 $a 0753
710 2 $a University of Colorado at Boulder. $b Physics. $3 1019557
773 0 $t Dissertation Abstracts International $g 68-11B.
790 $a 0051
790 1 0 $a Beale, Paul $e committee member
790 1 0 $a Bohn, John L. $e committee member
790 1 0 $a Cooper, John $e committee member
790 1 0 $a Holland, Murray, $e advisor
790 1 0 $a Lineberger, W. C. $e committee member
791 $a Ph.D.
792 $a 2007
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3284438