2014/04/26 by M. Bordag, Bordag, M., V. Skalozub +2
Physics and Astronomy · #Black Holes and Theoretical Physics #FOS: Physical sciences #High Energy Physics - Theory (hep-th) #Physics of Superconductivity and Magnetism #Quantum Chromodynamics and Particle Interactions #hep-th
paper · pdf · doi:10.48550/arxiv.1404.6658
16 pages, 4 figures
arxiv created 2014/04/26 · openalex publication_date 2014/04/26 · arxiv updated 2014/04/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We investigate the type of the temperature phase transition in the N component \la ϕ4 (O(N)) model of scalar fields. Actual calculations are carried out in the beyond-super-daisy approximation (BSDA). The cases N = 1 and larger N are considered separately. Using the solutions of gap equations we show that the character of the phase transition depends on the account for graphs BSDA. The role of different kinds of diagrams (especially the "sunset" one) is clarified. It is shown in a perturbation theory in the effective expansion parameter N- 1/3 that the kind of the phase transition depends on the value of coupling \la. It turns from a weak first-order to the second-order one for increasing \la. This is in agreement with the observation found recently for the O(1) model in Monte Carlo simulations on a lattice. Comparison with results of other authors is given.