Absorption of electromagnetic field energy by the superfluid system of atoms with a dipole moment

作者：Poluektov Yu M^*

来源：Low Temperature Physics, 2014, 40(5): 389-396.

DOI：10.1063/1.4881395

Absorption of electromagnetic energy by a superfluid system is considered on the basis of a modified Gross-Pitaevskii equation, which takes into account relaxation and interaction with an alternating electric field, under the assumption that the atoms possess an intrinsic dipole moment. It is shown that the absorption may exhibit a resonance behavior only if the dispersion curve of the electromagnetic wave and that of the excitations in the superfluid system intersect. It is noted that such a situation is possible if the superfluid system has an excitation branch with an energy gap at small momenta. Experiments on the absorption of microwave radiation in superfluid helium are interpreted as evidence for the existence of such gapped excitations. A possible modification of the excitation spectrum of superfluid helium in the presence of an excitation branch with an energy gap is discussed on a qualitative level.

• 出版日期2014-5