DOI: https://doi.org/10.30970/jps.03.264
ONCE MORE ON THE SUPERFLUID 4He
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Journal of Physical Studies 3(3), 264–271 (1999)
DOI: https://doi.org/10.30970/jps.03.264 ONCE MORE ON THE SUPERFLUID 4He |
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I. O. Vakarchuk
The Ivan Franko National University of Lviv, Chair of Theoretical Physics
12 Drahomanov Str., Lviv, UA-79005, Ukraine
Through the solution of motion equations for the density fluctuations of the many–particle system expressions for the energy spectrum, structural factor and free energy have been found. At the temperature $T→ 0$~K they yield the results of Bogoliubov theory and at high temperatures they tend to the corresponding expressions for the classical systems in the random phases approximation. The contribution of the non–linear fluctuations has also been taken into account. The obtained expressions are conducive to the study of $λ$–transition in liquid $^4$He.