Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221, USA.
Phys Rev Lett. 2012 Sep 14;109(11):110602. doi: 10.1103/PhysRevLett.109.110602. Epub 2012 Sep 12.
We study the sudden expansion of spin-imbalanced ultracold lattice fermions with attractive interactions in one dimension after turning off the longitudinal confining potential. We show that the momentum distribution functions of majority and minority fermions quickly approach stationary values due to a quantum distillation mechanism that results in a spatial separation of pairs and majority fermions. As a consequence, Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) correlations are lost during the expansion. Furthermore, we argue that the shape of the stationary momentum distribution functions can be understood by relating them to the integrals of motion in this integrable quantum system. We discuss our results in the context of proposals to observe FFLO correlations, related to recent experiments by Liao et al., Nature (London) 467, 567 (2010).
我们研究了在关闭纵向约束势后，一维具有吸引力相互作用的自旋非平衡超冷格子费米子的突然膨胀。我们表明，由于量子蒸馏机制导致对和多数费米子的对的空间分离，多数和少数费米子的动量分布函数很快接近稳定值。因此，在扩展过程中失去了 Fulde-Ferrell-Larkin-Ovchinnikov（FFLO）相关。此外，我们认为通过将它们与这个可积量子系统中的运动积分相关联，可以理解稳定动量分布函数的形状。我们在与廖等人最近的实验相关的观察 FFLO 相关的提议的背景下讨论了我们的结果，自然（伦敦）467,567（2010）。
