The Functional Forms of S (k) and E(k) in He II As Determined by Scattering Experiments

Abstract

The detailed form of the dispersion relation in He II has recently been the subject of intense interest.^1–5 The present discussion* was motivated by the work of Molinari and Regge² in which they suggested that the dispersion curve in He II might possess a term quadratic in the momentum. Their work was based on theoretical efforts as well as on computer fits to the data of Cowley and Woods¹ as shown in Fig. 1. In the work we shall describe here we have carried out fits to the data of Cowley and Woods, but in our case we have restricted attention to the small-angle data (k ≦ 1.0Å⁻¹).

Supported in part by the National Science Foundation and the University Computation Center of the University of Massachusetts.