Condensed Matter Physics, 2005, vol. 8, No. 4(44), p. 773-778, English

Title: Excitation spectrum and electrical properties of the condensate of Bose atoms
  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

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