Thermodynamics of pair production in a nondegenerate Fermi gas.

Johannes Hofmann, Marcus Barth

Christopher M. Wilson, Luigi Frunzio, D. E. Prober

We report on time-resolved measurements of thermodynamic fluctuations in the number of particles in a nondegenerate Fermi gas. The gas is comprised of thermal quasiparticles, confined in a superconducting Al box by large-gap Ta leads. The average number of quasiparticles is about 10(5). This number fluctuates due to quasiparticle generation and recombination. The number is measured from the tunneling current through a barrier that bisects the box. The recombination time is independently measured by single-photon excitation and agrees with the frequency dependence of the fluctuations.

Frédéric Chevy, Ch Salomon

Joseph M. Kinast

Olga Goulko, Matthew Wingate A

S. J. J. M. F. Kokkelmans, Georgy V. Shlyapnikov, Ch Salomon

We show that the atom-molecule mixture formed in a degenerate atomic Fermi gas with interspecies repulsion near a Feshbach resonance constitutes a peculiar system where the atomic component is almost nondegenerate but quantum degeneracy of molecules is important. We develop a thermodynamic approach for studying this mixture, explain experimental observations, and predict optimal conditions for achieving molecular Bose-Einstein condensation.