FIZIKA A 4 (1995) 3, 489-499

ELEMENTARY EXCITATION INTERACTIONS IN BOSE FLUIDS IN THE BOGOLIUBOV APPROXIMATION

SREĈKO KILIĈ
Faculty of Natural Sciences and Arts University of Split, Split, Croatia

Dedicated to Professor Mladen Paiĉ on the occasion of his 90^th birthday

Received 18 May 1995

The effective interaction energy of quasiparticles in the Bose fluid, which is described by "ladder state diagrams" in the Bogoliubov approximation, was studied for a model potential. It is shown that in the Bogoliubov approximation, the interaction of excitations in liquid  ⁴He  can not be described even qualitatively. It means that a model of the weakly interacting dilute Bose gas fails in describing the interaction between excitation in Bose-condensed liquid, although this model qualitatively incorporates superfluidity in itself.

UDC 538.94
PACS 05.30.Jp, 67.40.Db

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