Depletion of the Bose-Einstein condensate in Bose-Fermi mixtures
Depletion of the Bose-Einstein condensate in Bose-Fermi mixtures
复制标题
玻色-费米混合物中玻色-爱因斯坦凝聚态的耗尽
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
H. P. Buchler
中科院分区：
文献类型：
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作者：
Stephen Powell;S. Sachdev;H. P. Buchler
我们描述了费米子原子和玻色子原子的混合物的性质，当它们通过与费米子分子态相关的费什巴赫共振调谐时。如果费米子原子的数量超过玻色子原子的数量，我们认为存在一个临界失谐，在这个失谐点上玻色子-爱因斯坦凝聚体（BEC）完全耗尽。量子相变两侧的相也可以通过费米表面上不同的卢廷格约束来区分。在这两个阶段中，所有费米面包围的总体积受到费米子总数的限制。然而，在没有BEC的相位中，有两个费米面，存在第二个Luttinger约束：其中一个费米面所包围的体积受到玻色子总数的约束，因此两个费米面所包围的体积分别是守恒的。具有BEC的相可能有一个或两个费米面，但只有它们的总体积是守恒的。我们得到了作为原子参数和温度的函数的相图，并描述了所有跃迁附近的临界波动。我们对窄费什巴赫共振的情况进行了有效的定量预测，但我们希望我们描述的定性特征更普遍适用。作为题外话，我们指出了近藤晶格模型中BEC耗尽跃迁和向分馏费米液体跃迁之间的有趣联系。«少
We describe the properties of a mixture of fermionic and bosonic atoms, as they are tuned across a Feshbach resonance associated with a fermionic molecular state. Provided the number of fermionic atoms exceeds the number of bosonic atoms, we argue that there is a critical detuning at which the Bose-Einstein condensate (BEC) is completely depleted. The phases on either side of this quantum phase transition can also be distinguished by the distinct Luttinger constraints on their Fermi surfaces. In both phases, the total volume enclosed by all Fermi surfaces is constrained by the total number of fermions. However, in the phase without the BEC, which has two Fermi surfaces, there is a second Luttinger constraint: the volume enclosed by one of the Fermi surfaces is constrained by the total number of bosons, so that the volumes enclosed by the two Fermi surfaces are separately conserved. The phase with the BEC may have one or two Fermi surfaces, but only their total volume is conserved. We obtain the phase diagram as a function of atomic parameters and temperature, and describe critical fluctuations in the vicinity of all transitions. We make quantitative predictions valid for the case of a narrow Feshbach resonance,more » but we expect the qualitative features we describe to be more generally applicable. As an aside, we point out intriguing connections between the BEC depletion transition and the transition to the fractionalized Fermi liquid in Kondo lattice models.« less