Two-Dimensional Fermi Gas at Half Filling is a Luttinger Liquid

(Received 27 April 1995, accepted 6 July 1995)

Abstract
It is shown that in a model with a regular long range interaction, a 2D fermion gas at half filling of the band is a Luttinger Liquid. It is found that under certain conditions the jump in the momentum distribution of such a gas at the Fermi surface depends on the filling factor in the form , where is the range of the interaction and is a positive function of the position k on the Fermi surface. The jump vanishes when .