Relationship between the 1-D fermi gas model and other models

Jenő Sólyom

Brian K Tanner

Joachim Alexander Maruhn, P.‐G. Reinhard, E. Suraud

Jenő Sólyom

The Fermi gas model of one-dimensional conductors is reviewed. The exact solutions known for particular values of the coupling constants in a single chain problem (Tomonaga model, Luther-Emery model) are discussed. Renormalization group arguments are used to extend these solutions to arbitrary values of the couplings. The instabilities and possible ground states are studied by investigating the behaviour of the response functions. The relationship between this model and others is discussed and is used to obtain further information about the behaviour of the system. The model is generalized to a set of coupled chains to describe quasi-one-dimensional systems. The crossover from one-dimensional to three-dimensional behaviour and the type of ordering are discussed.

Hanoch Gutfreund

A.E. Delsante, Norman E. Frankel

A simple relationship between the pressure, internal energy, and Fermi energy of an ideal ultradegenerate Fermi gas is derived in two ways. The conditions for its validity and its use in simplifying calculations are discussed.