We discuss a new mechanism of microwave absorption in s- and d-wave superconductors, which arises in the presence of a dc supercurrent in the system. It produces a contribution to the ac conductivity that is proportional to the inelastic quasiparticle relaxation time. This contribution also determines the supercurrent dependence of the conductivity. It may significantly exceed the conventional contribution because in typical superconductors the inelastic relaxation time is several orders of magnitude longer than the elastic one. We show that the aforementioned contribution to the conductivity may be expressed in terms of the single particle density of states in superconductors in the presence of a dc supercurrent. Our results may enable determination of the inelastic relaxation time in superconductors from microwave absorption measurements.

中文翻译：

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s 波和 d 波超导体中的巨大微波吸收

我们讨论了 s 波和 d 波超导体中微波吸收的新机制，该机制在系统中存在直流超电流时出现。它对交流电导率的贡献与非弹性准粒子弛豫时间成正比。这种贡献也决定了电导率的超电流依赖性。它可能显着超过传统贡献，因为在典型的超导体中，非弹性弛豫时间比弹性弛豫时间长几个数量级。我们表明，上述对电导率的贡献可以用超导体中存在直流超电流时的单粒子态密度来表示。我们的结果可以通过微波吸收测量来确定超导体中的非弹性弛豫时间。