arXiv subjects

M. R. Setare

Publications and source records attributed to M. R. Setare.

214 records · Page 12Linked to original sources

arXiv2002

Holographic Thermodynamic on the Brane in Topological Reissner-Nordström de Sitter Space

We consider the brane universe in the bulk background of the topological Reissner-Nordström de Sitter black holes. We show that the thermodynamic quantities (including entropy) of the dual CFT take usual special forms expressed in terms of Hubble parameter and its time derivative at the moment, when the brane crosses the black hole horizon or the cosmological horizon. We obtain the generalized Cardy-Verlinde formula for the CFT with an charge and cosmological constant, for any values of the curvature parameter $k$ in the Friedmann equations.

hep-th↗

arXiv2002

The Cardy-Verlinde formula and entropy of Topological Reissner-Nordström black holes in de Sitter spaces

In this paper we discuss the question of whether the entropy of cosmological horizon in Topological Reissner-Nordström- de Sitter spaces can be described by the Cardy-Verlinde formula, which is supposed to be an entropy formula of conformal field theory in any dimension. Furthermore, we find that the entropy of black hole horizon can also be rewritten in terms of the Cardy-Verlinde formula for these black holes in de Sitter spaces, if we use the definition due to Abbott and Deser for conserved charges in asymptotically de Sitter spaces. Our result is in favour of the dS/CFT correspondence.

hep-th↗

arXiv2002

Cosmological Particle Creation and Dynamical Casimir Effect

In this paper we have considered the particle creation in the spatially closed Robertson-Walker space-time. We considered a real massive scalar field which conformally coupled to the Robertson-Walker background. With the dependence of the scale factor on time, the case under consideration is a dynamical Casimir effect with moving boundaries.

hep-th↗

arXiv2002

Casimir stress for cylindrical shell in de-Sitter space

The Casimir stress on cylinderical shell in de Sitter background for massless scalar field satisfying Dirichlet boundary conditions on the cylinder is calculated. The metric is written in conformally flat form to make maximum use of the Minkowski space calculations. Different cosmological constants are assumed for the space inside and outside the cylinder to have general results applicable to the case of cylindrical domain wall formations in the early universe.

hep-th↗

arXiv2002

Inhomogenous Poisson Networks and Random Cellular Structures

we study the statistical properties of inhomogenous Poisson networks. we perform a detailed analysis of the statistical properties of Poisson networks and show that the topological properties of random cellular structures, can be derived from these models of random networks. we study both two and three dimensional networks with non uniform density and show that with a class of symmetric distribution $P(λ_{1}, λ_{2}, ..., λ_{N})$ Lewis and Aboav-Weaire laws are obeyed in these networks.

cond-mat.stat-mech↗

arXiv2002

More on Phase Structure of Nonlocal 2D Generalized Yang-Mills Theories (nlgYM$_2$'s)

We study the phase structure of nonlocal two dimensional generalized Yang - Mills theories (nlgYM$_2$) and it is shown that all order of $ϕ^{2k}$ model of these theories has phase transition only on compact manifold with $g = 0$(on sphere), and the order of phase transition is 3. Also it is shown that the $ϕ^2 + \frac{2α}{3}ϕ^3$ model of nlgYM$_2$ has third order phase transition on any compact manifold with $1 < g < 1+ \frac{\hat{A}}{|η_c|}$, and has no phase transition on sphere.

hep-th↗

arXiv2002

Casimir energy for self-interacting scalar field in a spherical shell

In this paper we calculate the Casimir energy for spherical shell with massless self-interacting scalar filed which satisfying Dirichlet boundary conditions on the shell. Using zeta function regularization and heat kernel coefficients we obtain the divergent contributions inside and outside of Casimir energy. The effect of self-interacting term is similar with existing of mass for filed. In this case some divergent part arises. Using the renormalization procedure of bag model we can cancel these divergent parts.

hep-th↗

arXiv2002

Effective Action for Self-Interacting Scalar Field in 3-dimensional Ball

In this paper we have considered the renormalized one-loop effective action for massless self-interacting scalar field in the 3-dimensional ball. The scalar field satisfies Dirichlet boundary condition on the ball. Using heat kernel expansion method we calculate the divergent part of effective action, then by bag model renormalization procedure we obtain the renormalized one-loop effective action.

hep-th↗

arXiv2001

Particle creation in an oscillating spherical cavity

We study the creation of massless scalar particles from the quantum vacuum due to the dynamical Casimir effect by spherical shell with oscillating radius. In the case of a small amplitude of the oscillation, to solve the infinite set of coupled differential equations for the instantaneous basis expansion coefficients we use the method based on the time-dependent perturbation theory of the quantum mechanics. To the first order of the amplitude we derive the expressions for the number of the created particles for both parametric resonance and non-resonance cases.

hep-th↗

arXiv2001

Particle creation by moving spherical shell in the dynamical Casimir effect

The creation of massless scalar particles from the quantum vacuum by spherical shell with time varying radius is studied. In the general case of motion the equations are derived for the instantaneous basis expansion coefficients. The examples are considered when the mean number of particles can be explicitly evaluated in the adiabatic approximation.

hep-th↗

arXiv2001

Casimir stress for concentric spheres in de Sitter space

The Casimir stress on two concentric spherical shell in de Sitter background for massless scalar field is calculated. The scalar field satisfies Dirichlet boundary conditions on the spheres. The metric is written in conformally flat form to make maximum use of Minkowski space calculations. Then the Casimir stress is calculated for inside and outside of the shell with different backgrounds. This model may be used to study the effect of the Casimir stress on the dynamics of the domain wall formation in inflationary models of early universe.

hep-th↗

arXiv2001

Casimir stress on parallel plates in de Sitter space

The Casimir stress on two parallel plates in de Sitter background for massless scalar field satisfying Robin boundary conditions on the plates is calculated. The metric is written in conformally flat form to make maximum use of the Minkowski space calculations. Different cosmological constants are assumed for the space between and outside of the plates to have general results applicable to the case of domain wall formations in the early universe.

hep-th↗

arXiv2001

Trace anomaly and Casimir effect

The Casimir energy for scalar field of two parallel conductor in two dimensional domain wall background, with Dirichlet boundary conditions, is calculated by making use of general properties of renormalized stress tensor.We show that vacuum expectation values of stress tensor contain two terms which come from the boundary conditions and the gravitational background. In two dimensions the minimal coupling reduces to the conformal coupling and stress tensor can be obtained by the local and non-local contribution of the anomalous trace. This work shows that there exists a subtle relation between Casimir effect and trace anomaly in curved space time.

hep-th↗

arXiv2000

Casimir Effect, Hawking Radiation and Trace Anomaly

The Casimir energy for massless scalar field of two parallel conductor, in two dimensional Schwarzchild black hole background, with Dirichlet boundary conditions is calculated by making use of general properties of renormalized stress tensor. We show that vacuum expectation value of stress tensor can be obtain by Casimir effect, trace anomaly and Hawking radiation. Four-dimensional of this problem, by this method, is under progress by this author.

hep-th↗

arXiv2000

Casimir Effect for Spherical Shell in de Sitter Space

The Casimir stress on a spherical shell in de Sitter background for massless scalar field satisfying Dirichlet boundary conditions on the shell is calculated. The metric is written in conformally flat form. Although the metric is time dependent no particles are created. The Casimir stress is calculated for inside and outside of the shell with different backgrounds corresponding to different cosmological constants. The detail dynamics of the bubble depends on different parameter of the model. Specifically, bubbles with true vacuum inside expand if the difference in the vacuum energies is small, otherwise they collapse.

gr-qc↗

arXiv2000

Casimir Effect in Background of Static Domain Wall

In this paper we investigate the vacuum expectation values of energy- momentum tensor for conformally coupled scalar field in the standard parallel plate geometry with Dirichlet boundary conditions and on background of planar domain wall case. First we calculate the vacuum expectation values of energy-momentum tensor by using the mode sums, then we show that corresponding properties can be obtained by using the conformal properties of the problem. The vacuum expectation values of energy-momentum tensor contains two terms which come from the boundary conditions and the the gravitational background. In the Minkovskian limit our results agree with those obtained in [3].

hep-th↗