Temperature phase transition and an effective expansion parameter in the O(N)-model

Abstract

The temperature phase transition in the N-component scalar field theory with spontaneous symmetry breaking is investigated in the perturbative approach. The second Legendre transform is used together with the consideration of the gap equations in the extrema of the free energy. Resummations are performed on the super daisy level and beyond. The phase transition turns out to be weakly of first order. The diagrams beyond the super daisy ones which are calculated correspond to next-to-next-to-leading order in 1/N. It is shown that these diagrams do not alter the phase transition qualitatively. In the limit N goes to infinity the phase transition becomes second order. A comparison with other approaches is done.

28 pages, 5 figures, corrected for some misprints, unnecessary section removed

References in corpus (2)

• Phase transition in scalar ${\varphi }^4$-theory beyond the super daisy resummations
• On Symmetry Restoration at Finite Temperature (Scalar Case)

Cited by in corpus (3)

• Thermodynamics and phase transition of the O(N) model from the two-loop Phi-derivable approximation
• The O(N)-model within the Phi-derivable expansion to order lambda^2: on the existence, UV and IR sensitivity of the solutions to self-consistent equations
• Tachyon condensation in a chromomagnetic background field and the groundstate of QCD