论文标题
有效范围在密度诱导的BEC-BC交叉中的作用
Role of the effective range in the density-induced BEC-BCS crossover
论文作者
论文摘要
我们阐明了有效范围在三个维度的两组分支费米子的Bardeen-Cooper-Schrieffer（BCS）交叉状态中的有效范围对Bardeen-Cooper-Schrieffer（BCS）的跨界。与宽阔的Feshbach共振附近的超速费米气体相比，这种相互作用可以通过接触型相互作用来表征，通常在密度诱导的BEC-BCS交叉中，在凝结 - 凝结物和核系统中讨论的相互作用范围很重要。通过低能常数（例如散射长度$ a $ a $ a $ a $ a $ a $ a $ r $）来表征非本地互动，我们展示了分频现象如何受到非零有效范围的影响。特别是，我们表明，高密度方案中的超流体阶参数受到了强烈抑制，声音速度表现出反映系统机械稳定性的非单调行为。此外，我们指出，当动量$ k $的幅度少于$ 1/r $时，与接触参数相关的高摩肌尾巴可见。
We elucidate the role of the effective range in the Bose-Einstein-condensate (BEC) to Bardeen-Cooper-Schrieffer (BCS) crossover regime of two-component fermions in three dimensions. In contrast to ultracold Fermi gases near the broad Feshbach resonance, where the interaction can be characterized by the contact-type interaction, the interaction range in general becomes important in the density-induced BEC-BCS crossover discussed in the context of condensed-matter and nuclear systems. Characterizing the non-local interaction in terms of the low-energy constants such as scattering length $a$ and effective range $r$, we show how the crossover phenomena are affected by nonzero effective ranges. In particular, we show that the superfluid order parameter is strongly suppressed in the high-density regime and the sound velocity exhibits a non-monotonic behavior reflecting mechanical stability of the system. Moreover, we point out that the high-momentum tail associated with the contact parameter can be visible when the magnitude of momentum $k$ is much less than $1/r$.
