Superfluidity and Phase Coherence in Very Degenerate Atomic Gases

9614133 Leggett在过去的一年中，在三个不同的实验室中已经实现了稀原子气体中的玻色-爱因斯坦凝聚（BEC）现象，并且更多的实验室正在进入这一领域。 所讨论的系统存在于参数（密度、温度、隔离度）范围内。许多数量级不同于那些表征先前唯一已知的实验室系统被认为表现出BEC，即超流4 He。 因此，应该有可能使用这些系统进行实验测试各种想法，这些想法被认为适用于超流氦，但从未在那里进行过测试，特别是探索BEC和以“超流性”为名的复杂现象之间的精确关系。 理论工作将进行，在一般情况下，在稀释的原子气体的背景下，检查超流密度和零旋转和持续电流的现象的条件，并作出预测的一些有趣的实验的主题“量子相位相干性”和“相位记忆”，这显然是可行的，在这些系统。该补助金已与物理系的理论物理计划共同审查，并与他们共同资助。 这项资助支持了一位资深、杰出的PI的工作，他对超流和其他凝聚态现象（如宏观量子隧穿）的一般领域做出了许多深思熟虑的贡献。 这个项目的动机是最近的实验，把他带回到与玻色-爱因斯坦凝聚和稀释气体中的超流性之间的关系有关的问题。 该补助金已与物理系的理论物理计划共同审查，并与他们共同资助。 ***

9614133 Leggett Within the last year the phenomena of Bose-Einstein condensation (BEC) in dilute atomic gases has been realized in three different laboratories and many more are moving into this area. The systems in question lie in a regime of parameters (density, temperature, isolation _.) many orders of magnitude different from those which characterize the only previously known laboratory system believed to exhibit BEC, namely superfluid 4He. Consequently, it should be possible to use these systems to subject to experimental test a variety of ideas which are believed to apply to superfluid Helium but have never been tested there and in particular to explore the precise relation between BEC and the complex of phenomena which go under the name of "superfluidity". Theoretical work will be carried out, both in general and in the context of dilute atomic gases, to examine the superfluid density and the condition for the phenomena of zero rotation and of persistent currents, and to make predictions about a number of interesting experiments on the subject of "quantum phase coherence" and "phase memory" which are apparently feasible in these systems. This grant has been co-reviewed with the Theoretical Physics program in the Division of Physics and is being co-funded with them. %%% This grant supports the work of a senior, distinguished PI whose many thoughtful contributions to the general area of superfluidity and other condensed state phenomena (such as macroscopic quantum tunneling) are well known. This project, motivated by recent experiments, takes him back to the questions associated with relationship between Bose- Einstein condensation and superfluidity in dilute gases. This grant has been co-reviewed with the Theoretical Physics program in the Division of Physics and is being co-funded with them. ***