Achieving a BCS Transition in an Atomic Fermi Gas

Abstract

We consider a gas of cold fermionic atoms having two spin components with interactions characterized by their $s$-wave scattering length $a$. At positive scattering length the atoms form weakly bound bosonic molecules which can be evaporatively cooled to undergo Bose-Einstein condensation, whereas at negative scattering length BCS pairing can take place. It is shown that, by adiabatically tuning the scattering length $a$ from positive to negative values, one may transform the molecular Bose-Einstein condensate into a highly degenerate atomic Fermi gas, with the ratio of temperature to Fermi temperature $T/{T}_{F}\ensuremath{\sim}{10}^{\ensuremath{-}2}$. The corresponding critical final value of ${k}_{F}|a|$, which leads to the BCS transition, is found to be about one-half, where ${k}_{F}$ is the Fermi momentum.

Locations

• Physical Review Letters - View
• arXiv (Cornell University) - View - PDF
• Wiardi Beckman Foundation (Wiardi Beckman Foundation) - View - PDF
• HAL (Le Centre pour la Communication Scientifique Directe) - View
• PubMed - View
• DataCite API - View