2006/09/18 by Yatendra S. Jain, Jain, Yatendra S.
Physics and Astronomy · #FOS: Physical sciences #Soft Condensed Matter (cond-mat.soft) #cond-mat.soft
paper · pdf · doi:10.48550/arxiv.cond-mat/0609418
13 pages with 4 figures
arxiv created 2006/09/18 · arxiv updated 2009/12/01
Energy of elementary excitations and the anomalous nature of small Q phonons in He-II are studied by using our macro-orbital microscopic theory of a system of interacting bosons (cond-mat/0606571). It is observed that : (i) the experimental E(Q) of He-II not only agrees with our theoretical relation E(Q) = ℏ2Q2/4mS(Q) but also supports an important conclusion of Price that S(0) should have zero value for quantum fluids, and (ii) Feynman's energy of excitations E(Q)Fyn = ℏ2Q2/2mS(Q) equals approximately to 2E(Q)exp even at low Q. Three problems with the Feynman's inference that E(Q)Fyn has good agreement with E(Q)exp at low Q are identified. It is argued that the theory can also be used to understand similar spectrum of the BEC state of a dilute gas reported by O'Dell et al.