Iskin M, Sá de Melo C A R
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Phys Rev Lett. 2006 Sep 8;97(10):100404. doi: 10.1103/PhysRevLett.97.100404.
We analyze the phase diagram of uniform superfluidity for two-species fermion mixtures from the Bardeen-Cooper-Schrieffer to Bose-Einstein condensation (BEC) limit as a function of the scattering parameter and population imbalance. We find at zero temperature that the phase diagram of population imbalance versus scattering parameter is asymmetric for unequal masses, having a larger stability region for uniform superfluidity when the lighter fermions are in excess. In addition, we find topological quantum phase transitions associated with the disappearance or appearance of momentum space regions of zero quasiparticle energies. Lastly, near the critical temperature, we derive the Ginzburg-Landau equation and show that it describes a dilute mixture of composite bosons and unpaired fermions in the BEC limit.
我们分析了两分量费米子混合物从巴丁-库珀-施里弗（BCS）到玻色-爱因斯坦凝聚（BEC）极限的均匀超流相图，它是散射参数和粒子数不平衡的函数。我们发现在零温度下，对于质量不相等的情况，粒子数不平衡与散射参数的相图是不对称的，当较轻的费米子过量时，均匀超流具有更大的稳定区域。此外，我们发现了与零准粒子能量的动量空间区域的消失或出现相关的拓扑量子相变。最后，在临界温度附近，我们推导了金兹堡-朗道方程，并表明它描述了BEC极限下复合玻色子和未配对费米子的稀薄混合物。
