Related papers: Particle creation in a toroidal universe
The global topology of the Universe could, in principle, affect quantum systems through boundary condition constraints. We investigate this connection by analyzing how compact, flat, cosmologically inspired topologies, specifically the…
In this paper we present an exact solution to the spectrum of massless particle creation for a power law expansion of the scale factor of the form $t^{2n/3}$ for real scalar particles in a flat and matter dominated universe. Such an…
In this paper, we investigate cosmological particle production using quantum field theory (QFT). We will consider how production of scalar particles can occur in an expanding universe. By introducing a time-dependent energy parameter…
The spectrum of created particles during the tunneling process, leading to the decay of a false vacuum state, is studied numerically in the thick-wall approximation. It is shown that in this case the particle production is very intensive…
We calculate the average numbers of closed, flat, and open universes spontaneously created from nothing in third quantization. The creation of universes is exponentially suppressed for large values of the kinetic energy of the inflaton,…
A model of an emergent universe is formulated using the mechanism of particle creation. Here the universe is considered as a non-equilibrium thermodynamical system with dissipation due to particle creation mechanism. The universe is chosen…
The Universe evolution during the radiation-dominated epoch in the R^2-extended gravity theory is considered. The equations of motion for R and H are solved analytically and numerically. The particle production rate by the oscillating…
We study particle production in infrared-modified gravitational theories in the contemporary universe. It is shown that in astronomical systems with rising mass density, the curvature scalar may oscillate with very high frequency. These…
The particle creation by the so-called peak electric field is considered. The latter field is a combination of two exponential parts, one exponentially increasing and another exponentially decreasing. We find exact solutions of the Dirac…
We propose a modified form of the spontaneous birth of the universe by quantum tunneling. It proceeds through topology change and inflation, to eventually become a universe with closed spatial sections of negative curvature and nontrivial…
Using squeezed vacuum state formalism of quantum optics, an approximate solution to the semiclassical Einstein equation is obtained in Bianchi type-I universe. The phenomena of nonclassical particle creation is also examined in the…
We analyze the creation of particles in two dimensions under the action of conformal transformations. We focus our attention on Mobius transformations and compare the usual approach, based on the Bogolubov coefficients, with an alternative…
We construct models of universe with a generalized equation of state $p=(\alpha \rho+k\rho^{1+1/n})c^2$ having a linear component and a polytropic component. In this paper, we consider positive indices $n>0$. In that case, the polytropic…
We have obtained analytical exact solutions of the Dyer-Roeder equation in a cosmological model where creation of particles occurs at the expenses of the gravitational field. We discussed the influences of inhomogeneities in the path of a…
We calculate the probability of creation of a universe with space topology $S^{1}\times T_{g}$, where $S^{1}$ is the circle and $T_{g}$ is a compact hyperbolic surface of genus $g\geq 2$. We use the method of path integrals as applied to…
In this work an update of the cosmological role and place of the chiral tensor particles in the Universe history is provided. We discuss an extended model with chiral tensor particles. The influence of these particles on the early Universe…
A model for the Universe is proposed where it is considered as a mixture of scalar and matter fields. The particle production is due to an irreversible transfer of energy from the gravitational field to the matter field and represented by a…
The newly developed "void expansion method" allows for an efficient generation of porous packings of spherical particles over a wide range of volume fractions using the discrete element method. Particles are randomly placed under addition…
In the present paper, we solve the Dirac equation in the 2+1 dimensional exponentially expanding magnetized by uniform magnetic field and non-magnetized universes, separately. Asymptotic behaviors of the solutions are determined. Using…
With the help of a conformal, timelike Killing-vector we define generalized equilibrium states for cosmological fluids with particle production. For massless particles the generalized equilibrium conditions require the production rate to…