Eur. Phys. J. B 71, 7-14 (2009)
https://doi.org/10.1140/epjb/e2009-00261-9

The normal liquid ³He one-body momentum distribution at zero and finite temperature

¹ Physics Department, University of Tehran, North-Kargar Ave., 1439955961, Tehran, Iran
² Physics Department, Shahid Rajaei Teacher Training University, 16788, Tehran, Iran

Corresponding author: ^a mmodares@ut.ac.ir

Received: 18 February 2009
Revised: 7 June 2009
Published online: 21 July 2009

Abstract

The normal liquid helium 3 one-body momentum distribution, n(k), at zero and finite temperature is evaluated by using the cluster expansion theory for the occupation probability of Ristig-Clark formalism. The lowest order constrained variational (LOCV) and the extended LOCV (ELOCV) method are used to calculate the correlation functions at zero and finite temperatures. The input inter-atomic potential is the familiar 6–12 Lennard-Jones interaction. The gap in n(k) at the Fermi surface is found to be about 0.41 comparing to 1.0 (0.72) for the noninteracting (dilute hard-sphere) Fermi gas model at zero temperature and it decreases by increasing the temperature. It is also demonstrated that the high-momentum tail of n(k) gets larger as we increase the temperature and finally, we find a good agreement between present calculated n(k) and those coming from more sophisticated approaches such as Diffusion and Green-function Monte Carlo techniques.