Related papers: Effective Potential of $\lambda\phi^{4}_{1+3}$ at …
We compute the free energy of helium-4 near the lambda transition based on an exact renormalization-group equation. An approximate solution permits the determination of universal and nonuniversal thermodynamic properties starting from the…
The decay properties of the one-particle Green function in real space and imaginary time are systematically studied for solids. I present an analytic solution for the homogeneous electron gas at finite and at zero temperature as well as…
Scalar field theory with an asymmetric potential is studied at zero temperature and high-temperature for phi^4 theory with both phi and phi^3 symmetry breaking. The equations of motion are solved numerically to obtain O(4) symmetric and…
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 a $\phi^4$-theory at finite temperature in a finite volume. Quantum, thermal and volume fluctuations are treated with the functional renormalisation group. Specifically, we focus on the interplay of temperature and length scales…
The logarithmic sigma model describes the interactions between quarks via sigma and pion exchanges. The effective mesonic potential is extended to the finite temperature and it is numerically calculated using n-midpoint rule. Meson…
Dimensional reduction of finite temperature quantum field theories can be improved with help of continous renormalisation group steps. The method is applied to the integration of the lowest non-static ($n=\pm 1$) modes of the finite…
The renormalization group is used to improve the effective potential of massive ${\rm O}(N)$ symmetric $\phi^4$ theory. Explicit results are given at the two-loop level.
In this paper we discuss a disordered $d$-dimensional Euclidean $\lambda\varphi^{4}$ model. The dominant contribution to the average free energy of this system is written as a series of the replica partition functions of the model. In each…
Results of investigations of the O(4) spin model at finite temperature using anisotropic lattices are presented. In both the large $N$ approximation and the numerical simulations using the Wolff cluster algorithm we find that the ratio of…
We discuss the chiral symmetry restoration at high temperature and chemical potential for a four-fermion interaction theory in arbitrary dimensions ($2\leq D<4$). To investigate the ground state of the theory we calculate the effective…
We have proven the general relations between the gap equations obeyed by dynamical fermion mass and corresponding effective potentials at finite temperature and chemical potential in D dimensional four-fermion interaction models. This gives…
The restoration of spontaneous symmetry breaking for a scalar field theory for an accelerated observer is discussed by the one-loop effective potential calculation and by considering the effective potential for composite operators. Above a…
We investigate the impact of a uniform spin density on the critical temperature of the chiral phase transition in finite-temperature QCD in the scope of the linear sigma model. We demonstrate that at a finite spin potential $\mu_\Sigma$,…
We directly calculate spectral functions in the O(N)-model at finite temperature within the framework of the Functional Renormalization group. Special emphasis is put on a fully numerical framework involving four-dimensional regulators…
We make a Monte Carlo study of the coupled two-scalar $\lambda\phi^2_1\phi^2_2$ model in four dimensions at finite temperature. We find no trace of Inverse Symmetry Breaking for values of the renormalized parameters for which perturbation…
The decay rate for a particle in a metastable cubic potential is investigated in the quantum regime by the Euclidean path integral method in semiclassical approximation. The imaginary time formalism allows one to monitor the system as a…
Through two loop effective potential we demonstrate that the $\bar{MS}$ scheme of dimensional regularization and Jackiw's prescription in cut-off regularization allow for the dynamical breaking solution in massless $\lambda\phi^4$ theory,…
We evaluate the gauge invariant effective potential for the composite field $\sigma=2\Phi^{\dagger}\Phi$ in the SU(2)-Higgs model at finite temperature. Symmetric and broken phases correspond to the domains $\sigma\leq T^2/3$ and $\sigma >…
Many physical systems including lattices near structural phase transitions, glasses, jammed solids, and bio-polymer gels have coordination numbers that place them at the edge of mechanical instability. Their properties are determined by an…