Theory of trapped superfluid fermi gases

俘获超流体费米气体理论

基本信息

批准号：
4620-2006
负责人：
Griffin, Allan
金额：
$ 3.06万
依托单位：
University of Toronto
依托单位国家：
加拿大
项目类别：
Discovery Grants Program - Individual
财政年份：
2008
资助国家：
加拿大
起止时间：
2008-01-01 至 2009-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=389003
关键词：
Theory trapped superfluid fermi gases

项目摘要

Since the dramatic discovery in 1995 of Bose-Einstein condensation (BEC) in laser-cooled alkali atoms (after decades of effort), there has been a worldwide explosion of research on the properties of ultracold atoms and ultracold matter. BEC involves a macroscopic number of atoms occupying the same single-particle quantum state, which results in superfluid properties (persistent currents, quantized vortices, etc.) which are the analogue of those found in superfluid He and superconductors. My current research deals with trapped Fermi gases in the presence of a Feshbach resonance, which allows one to "tune" the size and sign of the s-wave scattering length (which completely describes the interatomic interaction at ultracold temperature). Because the interaction can be made very large in these Fermi gases, one can probe the two-fluid hydrodynamics at finite temperatures, first studied by Landau in 1941 in the context of superfluid liquid He. The Landau two-fluid equations should describe the dynamics across the entire BCS-BEC crossover (going from a BCS condensate of Cooper pairs to a BEC of real molecules). My work involves a detailed study of the two-fluid collective oscillations (the analogue of first and second sound in a uniform Bose superfluid). Superfluid Fermi gases with a Feshbach resonance allow us for the first time to probe the local equilibrium region of trapped quantum gases where collisions play a crucial role, even though the density is still extremely small. Experimental observation of two-fluid behaviour in trapped Fermi superfluid gases would be the complete analogue of the historic observations in 1938 of superfluidity in liquid Helium, although the detailed properties will be quite different in quantum gases because of the different thermodynamics.

由于在195年对Bose-Einstein凝结（BEC）的戏剧性发现以来，在激光冷却的碱原子中，关于超电原子和超电位物质的性质研究的研究爆发涉及宏观数量的原子。在超流体特性（持续的电流，量化的涡流是在超级流体和超导体中发现的类似物。我目前的研究Demi在Feshbach共振的存在中带有被困的费米气体，这允许一个人的大小和迹象“ s的大小和迹象” - 波散射长度“在超低温度下的作用）。在这些气体中可以使相互作用非常大，可以探测有限温度下的Tw-fluid流体动力学，应描述整个BCS-BEC交叉的动力学（从BCS转到BCS与真实分子的coop缩合在一起）。气体将在液氦中流动，Althooth的详细特性在不同的热力学的量子气体量中会大不相同。