Condensed Matter Physics, 2015, vol. 18, No. 4, 43001
First sound velocity in liquid 4He
(Department for Theoretical Physics, Ivan Franko National University of Lviv, 12 Drahomanov St., 79005 Lviv, Ukraine)
Based on the many-boson system structure factor, which takes into account three- and four-particle direct correlations,
there was found the first sound velocity temperature behaviour in liquid 4He
in the post-RPA approximation. The expression received for the sound velocity matches with the well-known results in both low and high temperature limits.
The results of this paper can be used to analyze the contributions of three- and four-particle correlations into thermodynamic and structural features of liquid 4He .
boson systems, liquid
PACS: 05.30.Jp, 67.25.-k, 43.35.+d, 62.60.+v,67.25.dt