The entropy and kinetic, potential, and interaction energies of an atomic Fermi gas in a trap are studied under the assumption of thermal equilibrium for finite temperature. A Feshbach resonance can cause the fermions to pair into diatomic molecules. The entropy and energies of mixtures of such molecules with unpaired atoms are calculated, in relation to recent experiments on molecular Bose-Einstein condensates produced in this manner. It is shown that, starting with a Fermi gas of temperature $T=0.1{T}_{F}^{0}$ , where ${T}_{F}^{0}$ is the noninteracting Fermi temperature, an extremely cold degenerate Fermi gas of temperature $T\ensuremath{\lesssim}0.01{T}_{F}^{0}$ may be produced without further evaporative cooling. This requires adiabatic passage of the resonance, subsequent sudden removal of unpaired atoms, and adiabatic return. We also calculate the ratio of the interaction energy to the kinetic energy, a straightforward experimental signal which may be used to determine the temperature of the atoms and indicate condensation of the molecules.The entropy and kinetic, potential, and interaction energies of an atomic Fermi gas in a trap are studied under the assumption of thermal equilibrium for finite temperature. A Feshbach resonance can cause the fermions to pair into diatomic molecules. The entropy and energies of mixtures of such molecules with unpaired atoms are calculated, in relation to recent experiments on molecular Bose-Einstein condensates produced in this manner. It is shown that, starting with a Fermi gas of temperature $T=0.1{T}_{F}^{0}$, where ${T}_{F}^{0}$ is the noninteracting Fermi temperature, an extremely cold degenerate Fermi gas of temperature $T\ensuremath{\lesssim}0.01{T}_{F}^{0}$ may be produced without further evaporative cooling. This requires adiabatic passage of the resonance, subsequent sudden removal of unpaired atoms, and adiabatic return. We also calculate the ratio of the interaction energy to the kinetic energy, a straightforward experimental signal which may be used to determine the temperature of the atoms and indicate condensation of the molecules.

arXiv:cond-mat/0405459Physical Review AOct 8, 20048 citations

The kinetic and interaction energies of a trapped Bose gas: beyond the mean field

Alexander Yu. Cherny, Arkady A Shanenko

arXiv:cond-mat/0105339Physics Letters AFeb 1, 200218 citations

Kinetics and Dynamics of Trapped Bose-condensed Gases

Peter O. Fedichev

Jan 1, 19990 citations

Momentum Distribution of a Fermi Gas of Atoms in the BCS-BEC Crossover

Cindy A. Regal, Markus Greiner, S. Giorgini +2 more

We observe dramatic changes in the atomic momentum distribution of a Fermi gas in the crossover region between the BCS theory superconductivity and Bose-Einstein condensation (BEC) of molecules. We study the shape of the momentum distribution and the kinetic energy as a function of interaction strength. The momentum distributions are compared to a mean-field crossover theory, and the kinetic energy is compared to theories for the two weakly interacting limits. This measurement provides a unique probe of pairing in a strongly interacting Fermi gas.We observe dramatic changes in the atomic momentum distribution of a Fermi gas in the crossover region between the BCS theory superconductivity and Bose-Einstein condensation (BEC) of molecules. We study the shape of the momentum distribution and the kinetic energy as a function of interaction strength. The momentum distributions are compared to a mean-field crossover theory, and the kinetic energy is compared to theories for the two weakly interacting limits. This measurement provides a unique probe of pairing in a strongly interacting Fermi gas.

arXiv:cond-mat/0507316Physical Review LettersDec 16, 200589 citations

Momentum distribution of an interacting Bose-Einstein condensed gas at finite temperature

Anna Minguzzi, Patrizia Vignolo, Mario P. Tosi

We use a semiclassical two-fluid model to study the momentum distribution of a Bose-Einstein condensed gas with repulsive interactions inside a harmonic trap at finite temperature, with specific focus on atomic hydrogen. We give particular attention to the average kinetic energy, which is almost entirely associated with the thermal cloud. A nonlinear dependence of the kinetic energy on temperature is displayed, affording a precise way to assess the temperature of the gas. We also show that the kinetic energy increases with the strength of the interactions, reflecting an enhanced rate of depletion of the condensate with increasing temperature.We use a semiclassical two-fluid model to study the momentum distribution of a Bose-Einstein condensed gas with repulsive interactions inside a harmonic trap at finite temperature, with specific focus on atomic hydrogen. We give particular attention to the average kinetic energy, which is almost entirely associated with the thermal cloud. A nonlinear dependence of the kinetic energy on temperature is displayed, affording a precise way to assess the temperature of the gas. We also show that the kinetic energy increases with the strength of the interactions, reflecting an enhanced rate of depletion of the condensate with increasing temperature.

arXiv:cond-mat/0003110Physical Review AJul 17, 200010 citations

Interaction energy of a Bose gas in a harmonic trap

Mingzhe Li, Haixiang Fu, You-Hua Luo +1 more

Physics Letters AAug 1, 20022 citations

T=0.1{T}_{F}^{0}

, where

{T}_{F}^{0}

is the noninteracting Fermi temperature, an extremely cold degenerate Fermi gas of temperature $T\ensuremath{\lesssim}0.01{T}_{F}^{0}$ may be produced without further evaporative cooling. This requires adiabatic passage of the resonance, subsequent sudden removal of unpaired atoms, and adiabatic return. We also calculate the ratio of the interaction energy to the kinetic energy, a straightforward experimental signal which may be used to determine the temperature of the atoms and indicate condensation of the molecules.