Related papers: Symmetry breaking in nonuniform noncommutative $\l…
We discuss the nature of the finite-temperature transition in QCD with N_f massless flavors. Universality arguments show that a continuous (second-order) transition must be related to a 3-D universality class characterized by a complex N_f…
We study conformal field theories with finite group symmetries with spontaneous symmetry breaking (SSB) phases that persist at all temperatures. We work with two $\lambda \phi^4$ theories coupled through their mass terms. The two $\lambda…
We assume that the noncommutativity starts to be visible continuously from a scale $\Lambda_{NC}$. According to this assumption, a two-loop effective action is derived for noncommutative $\phi^{4}$ and $\phi^{3}$ theories from a Wilsonian…
I review the use of the 2PI effective action in nonequilibrium quantum field theory. The approach enables one to find approximation schemes which circumvent long-standing problems of non-thermal or secular (unbounded) late-time evolutions…
We calculate the explicit expression of the effective potential in a $\lambda\phi^4$ theory at finite temperature in a static universe for arbitrary spacetime dimensions (2\leq D < 5). To study the combined effects of the temperature and…
The four dimensional critical scalar theory at equilibrium with a thermal bath at temperature $T$ is considered. The thermal equilibrium state is labeled by $n$ the winding number of the vacua around the compact imaginary-time direction…
We investigate the phase structure of non-commutative scalar field theories and find evidence for ordered phases which break translation invariance. A self-consistent one-loop analysis indicates that the transition into these ordered phases…
We study the behavior of two diferent models at finite temperature in a $D$-dimensional spacetime. The first one is the $\lambda\varphi^{4}$ model and the second one is the Gross-Neveu model. Using the one-loop approximation we show that in…
We study thermal effects for a noncommutative real scalar field in 2+1 dimensions including a Grosse-Wulkenhaar term. Using a perturbative expansion for the free energy, we deduce some general properties of the corresponding contributions,…
We present a numerical study of the \lambda \phi^{4} model in three Euclidean dimensions, where the two spatial coordinates are non-commutative (NC). We first show the explicit phase diagram of this model on a lattice. The ordered regime…
We present a self-consistent calculation of the finite temperature effective potential for $\lambda \Phi^4$ theory in four dimensions using a composite operator effective action. We find that in a spontaneously broken theory not only the…
The Gaussian-time-dependent variational equations are used to explored the physics of $(\phi^4)_{3+1}$ field theory. We have investigated the static solutions and discussed the conditions of renormalization. Using these results and…
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…
We study a non-commutative non-relativistic scalar field theory in 2+1 dimensions. The theory shows the UV/IR mixing typical of QFT on non-commutative spaces. The one-loop correction to the two-point function turns out to be given by a…
We present a first numerical investigation of a non-commutative gauge theory defined via the spectral action for Moyal space with harmonic propagation. This action is approximated by finite matrices. Using Monte Carlo simulation we study…
We analyze the spontaneous $U(1)_R$ symmetry breaking at finite temperature for the simple O'Raifeartaigh-type model introduced in [1] in connection with spontaneous supersymmetry breaking. We calculate the finite temperature effective…
The quantum dynamics of the symmetry broken \lambda (\Phi^2)^2 scalar field theory in the presence of an homogeneous external field is investigated in the large N limit. We consider an initial thermal state of temperature T for a constant…
Spontaneous symmetry breaking occurs when the underlying laws of a physical system are symmetric, but the vacuum state chosen by the system is not. The (3+1)d $\phi^4$ theory is relatively simple compared to other more complex theories,…
In this work we consider the 1-component real scalar $\phi^4$ theory in 4 space-time dimensions on the lattice and investigate the finite size scaling of thermodynamic quantities to study whether the thermodynamic limit is attained. The…
A semiclassical picture of spontaneous symmetry breaking in light front field theory is formulated. It is based on a finite-volume quantization of self-interacting scalar fields obeying antiperiodic boundary conditions. This choice avoids a…