We theoretically investigate dynamic structure factors of a strongly interacting Fermi superfluid near an orbital Feshbach resonance with random phase approximation approach at zero temperature, and find their dynamical characters across the phase transition from a balanced conventional Bardeen-Cooper-Schrieffer (BCS) superfluid to a polarized Sarma superfluid by continuously varying the chemical potential difference of two spin components. In a Bose-Einstein-condensate-like regime of the Fermi superfluid, dynamic structure factors can help distinguish the in-phase ground state from the out-of-phase metastable state by the relative location of molecular excitation and Leggett mode, or the minimum energy to break a Cooper pair. In the phase transition from BCS to Sarma superfluid, we find the dynamic structure factor of Sarma superfluid has its own specific gapless excitation at a small transferred momentum where the collective phonon excitation acquires a finite width, and also a relatively strong atomic excitation at a large transferred momentum, because of the existence of unpaired Fermi atoms. Our results can be used to differentiate Sarma superfluid from BCS superfluid.

中文翻译：

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在从BCS到Sarma超流体的相变中，强相互作用的费米超流体在轨道Feshbach共振附近的动力学结构因子

我们从理论上研究了在零温度下采用随机相位逼近方法在轨道Feshbach共振附近强烈相互作用的费米超流体的动力学结构因子，并发现了它们在从平衡的常规Bardeen-Cooper-Schrieffer（BCS）超流体到相变的整个相变过程中的动力学特征。通过不断改变两个自旋成分的化学势差来使极化的Sarma超流体极化。在费米超流体的玻色-爱因斯坦凝聚态下，动态结构因子可以通过分子激发和Leggett模式的相对位置或最小来帮助区分同相基态和异相亚稳态。打破库珀配对的能量。在从BCS到Sarma超流体的阶段过渡中，我们发现Sarma超流体的动力学结构因子在较小的传递动量下具有其特定的无间隙激发，其中集体声子激发获得有限的宽度，并且在较大的传递动量下也具有相对较强的原子激发，这是由于存在不成对的费米原子。我们的结果可用于区分Sarma超流体和BCS超流体。