论文标题
关于超流量声子的有效理论
On Effective Theory of Superfluid Phonons
论文作者
论文摘要
结果表明，非相关性超流体的标准有效场理论（仅包括衍生物扩张中的主要顺序作用）通常不足以研究超音速过程。也就是说，为了对后者进行适当的处理，具有大于$ mc_s $的音位有时是相关的（$ m $是超级流体组成部分的质量，而表示声速的$ C_S $），这超出了上面提到的幼稚有效理论的有效性。通过将已知的摩擦力表达式作为超音速perturber辐射声子的过程，在一个具体的示例上证明了这一点。特别是，当杂质比超流体成分重时，确实有必要扩展超流体的非相关性有效理论，以包括高衍生的校正。然而，对于光线，有一个速度窗口，高衍生的校正是无关紧要的。
It is shown that the standard effective field theory of non-relativistic superfluids, which includes only the leading order action in derivative expansion, is in general inadequate for studying supersonic processes. Namely, for a proper treatment of the latter the phonons with momenta greater than $mc_s$ are relevant at times (with $m$ being the mass of the superfluid constituent and $c_s$ denoting the sound-speed), which lie beyond the regime of validity of the naive effective theory mentioned above. This is demonstrated on a concrete example by recovering the known expression for the friction force as a process of radiating phonons by a supersonic perturber. In particular, when the impurity is heavier than superfluid constituents, it is indeed necessary to extend the non-relativistic effective theory of superfluids to include high-derivative corrections. For the light perturber, however, there is a window of velocities for which high-derivative corrections are irrelevant.
