Roton dipole moment
V. P. Mineev
Commissariat à l'Energie Atomique, INAC/SPSMS, 38054 Grenoble, France
PACS: 67.10.-j, 67.25.-k
Abstract
The roton excitation in the superfluid 4He does not possess a
stationary dipole moment. However, a roton has an instantaneous dipole
moment, such that at any given moment one can find it in the state either
with positive or with negative dipole moment projection on its momentum
direction. The instantaneous value of electric dipole moment of roton
excitation is evaluated. The result is in reasonable agreement with recent
experimental observation of the splitting of microwave resonance absorption
line at roton frequency under external electric field.