Particle creation from vacuum in homogeneous isotropic models of the Universe

Grib, A. A.; Mamayev, S. G.; Mostepanenko, V. M.

doi:10.1007/bf00766413

Cited by 138 publications

(104 citation statements)

References 11 publications

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“…Reheating could be produced due to the gravitational particle creation in an expanding Universe [25,26]. In this case, an abrupt phase transition (a non-adiabatic transition) is needed in order to obtain sufficient particle creation that thermalizes, producing a reheating temperature that fits well with current observations.…”

Section: Introductionmentioning

confidence: 84%

An extended matter bounce scenario: current status and challenges

Haro

Cai

2015

Gen Relativ Gravit

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As an alternative to the paradigm of slow roll inflation, we propose an extended scenario of the matter bounce cosmology in which the Universe has experienced a quasi-matter contracting phase with a variable background equation of state parameter. This extended matter bounce scenario can be realized by considering a single scalar field evolving along an approximately exponential potential. Our result reveals that the rolling of the scalar field in general leads to a running behavior on the spectral index of primordial cosmological perturbations and a negative running can be realized in this model. We constrain the corresponding parameter space by using the newly released Planck data. To apply this scenario, we revisit bouncing cosmologies within the context of modified gravity theories, in particular, the holonomy corrected loop quantum cosmology and teleparallel F (T ) gravity. A gravitational process of reheating is presented in such a matter bounce scenario to demonstrate the condition of satisfying current observations. We also comment on several unresolved issues that often appear in matter bounce models.

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Section: Introductionmentioning

confidence: 84%

An extended matter bounce scenario: current status and challenges

Haro

Cai

2015

Gen Relativ Gravit

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“…In order to derive the pair creation rate we have at our disposal several methods such as the method based on vacuum to vacuum transition amplitude and Schwinger-like effective action [2,43], the Hamiltonian diagonalization technique [44,45], the Feynman path integral method [46,47] as well as the semiclassical WKB approximation [48,49] and the "in" and "out" states formalism [50,51] that we shall use in this work.…”

Section: Usual Theory Of Particle Creationmentioning

confidence: 99%

Influence of a minimal length on the creation of scalar particles

Haouat

Nouicer

2014

Phys. Rev. D

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In this paper we have studied the problem of scalar particles pair creation by an electric field in the presence of a minimal length. Two sets of exact solutions for the Klein Gordon equation are given in momentum space. Then the canonical method based on Bogoliubov transformation connecting the "in" with the "out" states is applied to calculate the probability to create a pair of particles and the mean number of created particles. The number of created particles per unit of time per unit of length, which is related directly to the experimental measurements, is calculated. It is shown that, with an electric field less than the critical value, the minimal length minimizes the particle creation. It is shown, also, that the limit of zero minimal length reproduces the known results corresponding to the ordinary quantum fields.

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“…Instead of (52), in order to calculate u k , one has to use the exact expression given by formula (27).…”

Section: Calculation Of the Power Spectrum Of Scalar Perturbations Inmentioning

confidence: 99%

Viability of the matter bounce scenario inF(T) gravity and Loop Quantum Cosmology for general potentials

Haro

Amorós

2014

J. Cosmol. Astropart. Phys.

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We consider the matter bounce scenario in F (T ) gravity and Loop Quantum Cosmology (LQC) for phenomenological potentials that at early times provide a nearly matter dominated Universe in the contracting phase, having a reheating mechanism in the expanding or contracting phase, i.e., being able to release the energy of the scalar field creating particles that thermalize in order to match with the hot Friedmann Universe, and finally at late times leading to the current cosmic acceleration. For these potentials, numerically solving the dynamical perturbation equations we have seen that, for the particular F (T ) model that we will name teleparallel version of LQC, and whose modified Friedmann equation coincides with the corresponding one in holonomy corrected LQC when one deals with the flat Friedmann-Lemaître-Robertson-Walker (FLRW) geometry, the corresponding equations obtained from the well-know perturbed equations in F (T ) gravity lead to theoretical results that fit well with current observational data. More precisely, in this teleparallel version of LQC there is a set of solutions which leads to theoretical results that match correctly with last BICEP2 data, and there is another set whose theoretical results fit well with Planck's experimental data. On the other hand, in the standard holonomy corrected LQC, using the perturbed equations obtained replacing the Ashtekar connection by a suitable sinus function and inserting some counter-terms in order to preserve the algebra of constrains, the theoretical value of the tensor/scalar ratio is smaller than in the teleparallel version, which means that there is always a set of solutions that matches with Planck's data, but for some potentials BICEP2 experimental results disfavours holonomy corrected LQC.

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Particle creation from vacuum in homogeneous isotropic models of the Universe

Cited by 138 publications

References 11 publications

An extended matter bounce scenario: current status and challenges

An extended matter bounce scenario: current status and challenges

Influence of a minimal length on the creation of scalar particles

Viability of the matter bounce scenario inF(T) gravity and Loop Quantum Cosmology for general potentials

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