Variational Study of the Phase Transition at Finite T in the $\lambda {\varphi }^4$-Theory

G. Palma, J. C. Rojas

Assuming triviality of the 4-dimensional $\lambda {\varphi }^4$-theory we compute the effective potential by means of a self consistent Feynman-Bogoliubov method. This potential $U_{eff}^{FB}$ dep…