Bulk viscosity of resonating fermions revisited: Kubo formula, sum rule, and the dimer and high-temperature limits
Bulk viscosity of resonating fermions revisited: Kubo formula, sum rule, and the dimer and high-temperature limits
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重温共振费米子的体积粘度：Kubo 公式、总和规则以及二聚体和高温限制
DOI：
10.1103/physreva.102.023310
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发表时间：
2020
影响因子：
2.9
通讯作者：
Nishida Yusuke
中科院分区：
文献类型：
--
作者：
Fujii Keisuke;Nishida Yusuke
本文在二维和三维两维中重新讨论了零程相互作用下双组分费米子的体粘滞系数。我们首先指出，“标准”久保公式在最近的研究中有缺陷，引起一个非物理发散的体积粘度，即使在一个极限，它应该消失。修正后的久保公式以及求和规则，然后，仔细重新推导，以确认体积粘度，的确，消失在自由，酉，和二聚体的限制。我们还讨论了最近发现的Kubo形式主义和动力学理论的体积粘度之间的差异归因于这样一个事实，即后者假设的准粒子近似即使在高温极限下也会崩溃。
The bulk viscosity of two-component fermions with a zero-range interaction is revisited both in two and three dimensions. We first point out that the “standard” Kubo formula employed in recent studies has flaws to give rise to an unphysical divergent bulk viscosity even in a limit where it is supposed to vanish. The corrected Kubo formula as well as the sum rule is, then, carefully rederived so as to confirm that the bulk viscosity, indeed, vanishes in the free, unitarity, and dimer limits. We also discuss that the recently found discrepancy between the Kubo formalism and the kinetic theory for the bulk viscosity is attributed to the fact that the quasiparticle approximation assumed by the latter breaks down even in the high-temperature limit.