Autori: E. Prodan and P. Nordlander

Editorial: J. Math. Phys., 42, p.3424-3438, 2001.

Rezumat:

We consider a one dimensional fermionic gas confined on a circle of finite length. At finite temperatures, in the absence of any background potential, one can show that a constant density of particles is a solution to the Hartree equation, regardless of the type of interparticle interaction. Moreover, at finite temperatures and small coupling constants, our previous analysis shows that this is the only solution of the Hartree equations. We show in this paper that, at zero temperature, there is another solution, which has an asymptotic expansion: n(x)=n0(1+ct.cos2k_{F}x)+o(lamda), where lamda is the coupling constant. Moreover, this solution is stable while the trivial solution become unstable at zero temperature.

Cuvinte cheie: many-body, continuous symmetry breaking