Koch Jennifer, Barbosa Sian, Lang Felix, Widera Artur
Department of Physics and Research Center OPTIMAS, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany.
TOPTICA Photonics AG, Gräfelfing, Germany.
Nat Commun. 2024 Oct 28;15(1):9292. doi: 10.1038/s41467-024-51903-8.
The microscopic pair structure of superfluids has profound consequences on their properties. Delocalized pairs are predicted to be less affected by static disorder than localized pairs. Ultracold gases allow tuning the pair size via interactions, where for resonant interaction superfluids show largest critical velocity, i.e., stability against perturbations. The sensitivity of such fluids to strong, time-dependent disorder is less explored. Here, we investigate ultracold, interacting Fermi gases across various interaction regimes after rapid switching optical disorder potentials. We record the ability for quantum hydrodynamic expansion of the gas to quantify its long-range phase coherence. Contrary to static expectations, the Bose-Einstein condensate (BEC) exhibits significant resilience against disorder quenches, while the resonantly interacting Fermi gas permanently loses quantum hydrodynamics. Our findings suggest an additional absorption channel perturbing the resonantly interacting gas as pairs can be directly affected by the disorder quench.
超流体的微观配对结构对其性质有着深远影响。预计离域配对比局域配对受静态无序的影响更小。超冷气体可通过相互作用调节配对尺寸，其中对于共振相互作用的超流体，其临界速度最大，即对微扰具有稳定性。此类流体对强的、随时间变化的无序的敏感性研究较少。在此，我们在快速切换光学无序势后，研究了处于各种相互作用区域的超冷相互作用费米气体。我们记录气体的量子流体动力学膨胀能力，以量化其长程相位相干性。与静态预期相反，玻色 - 爱因斯坦凝聚体（BEC）对无序猝灭表现出显著的恢复能力，而共振相互作用的费米气体则永久性地失去了量子流体动力学特性。我们的研究结果表明，存在一个额外的吸收通道干扰共振相互作用的气体，因为配对会直接受到无序猝灭的影响。
