Spontaneous symmetry restoration in a field theory at finite chemical   potential in a toroidal topology
  We consider the massive vector $N$-component $(\lambda\varphi^{4})_{D}$ theory defined on a Euclidean space with a toroidal topology. Using recently developed methods to perform a compactification of a $d$-dimensional subspace at finite chemical potential, we treat jointly the effects of temperature and spatial boundaries, setting forth grounds for an analysis of spontaneous symmetry restoration driven by temperature and spatial boundaries as a function of the chemical potential. We restrict ourselves to d=2, which corresponds to the heated system confined between two parallel planes (separation $L$) in dimensions D=3 and D=4. We present results, in the large-$N$ limit, which exhibit how finite size and chemical potential affect spontaneous symmetry restoration. 
C. A. Linhares, A. P. C. Malbouisson, J. M. C. Malbouisson, I. Roditi
hep-th cond-mat.stat-mech hep-ph math-ph math.MP