Feasibility of a Fulde-Ferrell-Larkin-Ovchinnikov superfluid Fermi atomic gas
Feasibility of a Fulde-Ferrell-Larkin-Ovchinnikov superfluid Fermi atomic gas
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Fulde-Ferrell-Larkin-Ovchinnikov 超流体费米原子气体的可行性
DOI：
10.1103/physreva.106.033320
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发表时间：
2022
影响因子：
2.9
通讯作者：
Yoji Ohashi
中科院分区：
文献类型：
--
作者：
Taira Kawamura;Yoji Ohashi
我们从理论上探索了一条在自旋不平衡超冷费米气体中实现 Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) 态的有前途的途径。在冷原子物理的现阶段，寻找这种奇异的费米超流体面临着两个严重的困难：一是FFLO配对涨落对FFLO长程有序的绝望破坏，这阻碍了通过二阶跃迁进入相，即使在三维空间也是如此。另一个是相分离进入BCS（Bardeen-Cooper-Schrieffer）态和自旋极化正常态的激烈竞争。通过将强 FFLO 配对涨落纳入 Nozières 和 Schmitt-Rink 开发的强耦合理论框架内，我们表明光学晶格引入的费米表面的各向异性使得 FFLO 状态相对于配对涨落保持稳定。这种稳定的FFLO状态还被发现能够在一定条件下克服与相分离的竞争。由于非常规费米超流体的实现是冷原子物理学中最令人兴奋的挑战之一，我们的结果将有助于该领域的进一步发展。
We theoretically explore a promising route to achieve the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state in a spin-imbalanced ultracold Fermi gas. In the current stage of cold atom physics, search for this exotic Fermi superfluid is facing two serious difficulties: One is the desperate destruction of the FFLO long-range order by FFLO pairing fluctuations, which precludes entering the phase through a second-order transition, even in three dimension. The other is the fierce competition with the phase separation into the BCS (Bardeen-Cooper-Schrieffer) state and the spin-polarized normal state. By including strong FFLO pairing fluctuations within the framework of the strong-coupling theory developed by Nozières and Schmitt-Rink, we show that the anisotropy of Fermi surface introduced by an optical lattice makes the FFLO state stable against the paring fluctuations. This stabilized FFLO state is also found to be able to overcome the competition with the phase separation under a certain condition. Since the realization of unconventional Fermi superfluids is one of the most exciting challenges in cold atom physics, our results would contribute to the further development of this field.