Title: Excitation spectrum and electrical properties of the condensate of Bose atoms
Author(s):

A.M.Kosevich (B.Verkin Institute for Low Temperature Physics and Engineering of National Academy of Sciences of Ukraine, 47, Lenin Avenue, Kharkiv, 61103 Ukraine) ,

It is shown that the condensate of a degenerated Bose gas consisting of neutral atoms possesses electrical properties which differ from a trivial polarization of the atoms in the electric field. A notion of an isotropic quadrupole moment (IQM) of a neutral atom is introduced. A distribution of IQM reflects a specific spatial ordering in the condensate and produces a distribution of the electric potential. Small vibrations of the Bose gas are considered and a correction to the Bogoliubov spectrum of elementary excitations in the degenerated Bose gas is obtained. An additional term in the Gross-Pitaevskii equation which is responsible for such a correction is found and a new type of the nonlinear Schrödinger equation (NSE) is constructed. Since the Bose condensate is akin to the superfluid component in He II, a manifestation of its electrical activity could have a relation to the electrical activity of the superfluid liquid observed experimentally.

Key words: Bose condensate, Bogoliubov spectrum, electrical polarization of He II
PACS: 47.27.Eq, 67.40.Db