Quantum-mechanical analogue of particle creation caused by the expansion of the universe

1973 ◽  
Vol 17 (2) ◽  
pp. 284-299 ◽  
Author(s):  
J. Audretsch
Keyword(s):  
Particle Creation ◽  
Quantum Mechanical ◽  
Mechanical Analogue ◽  
Expansion Of The Universe ◽  
The Universe

scholarly journals Creation of mass dimension one fermionic particles in asymptotically expanding universe

2017 ◽  
Vol 26 (12) ◽  
pp. 1730028 ◽  
Author(s):  
S. H. Pereira ◽  
Rodrigo C. Lima
Keyword(s):  
Dark Matter ◽  
Scalar Field ◽  
Particle Creation ◽  
Analytic Solutions ◽  
Coupling Case ◽  
Mass Dimension ◽  
Fermionic Fields ◽  
Expansion Of The Universe ◽  
Dimension One ◽  
The Universe

In the present work we study the process of particle creation for mass dimension one fermionic fields (sometimes named Elko) as a consequence of expansion of the universe. We study the effect driven by an expanding background that is asymptotically Minkowski in the past and future. The differential equation that governs the time mode function is obtained for the conformal coupling case and, although its solution is nonanalytic, within an approximation that preserves the characteristics of the terms that break analyticity, analytic solutions are obtained. Thus, by means of Bogolyubov transformations technique, the number density of particles created is obtained, which can be compared to exact solutions already present in literature for scalar and Dirac particles. The spectrum of the created particles was obtained and it was found that it is a generalization of the scalar field case, which converges to the scalar field one when the specific terms concerning the Elko field are dropped out. We also found that lighter Elko particles are created in larger quantities than the Dirac fermionic particles. By considering the Elko particles as candidate to the dark matter in the universe, such result shows that there are more light dark matter (Elko) particles created by the gravitational effects in the universe than baryonic (fermionic) matter, in agreement to the standard model.

scholarly journals QUANTUM-TO-CLASSICAL TRANSITION FOR FLUCTUATIONS IN THE EARLY UNIVERSE

1998 ◽  
Vol 07 (03) ◽  
pp. 455-462 ◽  
Author(s):  
CLAUS KIEFER ◽  
DAVID POLARSKI ◽  
ALEXEI A. STAROBINSKY
Keyword(s):  
Early Universe ◽  
Field Amplitude ◽  
Quantum Mechanical ◽  
Gravitational Effects ◽  
Inflationary Scenario ◽  
Classical Transition ◽  
Expansion Of The Universe ◽  
Hubble Radius ◽  
The Universe ◽  
Specific Quantum

According to the inflationary scenario for the very early Universe, all inhomogeneities in the Universe are of genuine quantum origin. On the other hand, looking at these inhomogeneities and measuring them, clearly no specific quantum mechanical properties are observed. We show how the transition from their inherent quantum gravitational nature to classical behavior comes about — a transition whereby none of the successful quantitative predictions of the inflationary scenario for the present-day universe is changed. This is made possible by two properties. First, the quantum state for the spacetime metric perturbations produced by quantum gravitational effects in the early Universe becomes very special (highly squeezed) as a result of the expansion of the Universe (as long as the wavelength of the perturbations exceeds the Hubble radius). Second, decoherence through the environment distinguishes the field amplitude basis as being the pointer basis. This renders the perturbations presently indistinguishable from stochastic classical inhomogeneities.

Black Hole Universe: a grand cosmic recycler and Big Bang generator?

2019 ◽  
Author(s):  
Matheus Pereira Lobo
Keyword(s):  
Black Hole ◽  
Big Bang ◽  
Subsequent Increase ◽  
Expansion Of The Universe ◽  
The Universe

We propose the discussion of a highly speculative idea for the scenario where black hole collisions and their subsequent increase in sizes exceed the expansion of the universe.

Cosmological constant

2018 ◽  
Author(s):  
Michael Kachelriess
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Accelerated Expansion ◽  
Vacuum Fluctuations ◽  
Present Epoch ◽  
Modify Gravity ◽  
Expansion Of The Universe ◽  
The Universe

The contribution of vacuum fluctuations to the cosmological constant is reconsidered studying the dependence on the used regularisation scheme. Then alternative explanations for the observed accelerated expansion of the universe in the present epoch are introduced which either modify gravity or add a new component of matter, dubbed dark energy. The chapter closes with some comments on attempts to quantise gravity.

scholarly journals Mixed fluid cosmological model in f(R, T) gravity

2020 ◽  
Vol 98 (11) ◽  
pp. 1015-1022 ◽  
Author(s):  
Parbati Sahoo ◽  
Barkha Taori ◽  
K.L. Mahanta
Keyword(s):  
Cosmological Model ◽  
Bianchi Type ◽  
Type I ◽  
Time Varying ◽  
Eos Parameter ◽  
Barotropic Fluid ◽  
Rotationally Symmetric ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Mixed Fluid

We construct a locally rotationally symmetric (LRS) Bianchi type-I cosmological model in f(R, T) theory of gravity when the source of gravitation is a mixture of barotropic fluid and dark energy (DE) by employing a time-varying deceleration parameter. We observe through the behavior of the state finder parameters (r, s) that our model begins from the Einstein static era and goes to ΛCDM era. The equation of state (EOS) parameter (ωd) for DE varies from the phantom (ω < –1) phase to quintessence (ω > –1) phase, which is consistent with observational results. It is found that the discussed model can reproduce the current accelerating phase of the expansion of the universe.

scholarly journals IMPLICATIONS OF A QUANTUM MECHANICAL TREATMENT OF THE UNIVERSE

1998 ◽  
Vol 13 (05) ◽  
pp. 347-351 ◽  
Author(s):  
MURAT ÖZER
Keyword(s):  
Quantum Mechanics ◽  
Wave Packet ◽  
Early Universe ◽  
Mechanical Treatment ◽  
Correspondence Principle ◽  
Scale Factor ◽  
Quantum Mechanical ◽  
Quantum Mechanical Treatment ◽  
The Standard Model ◽  
The Universe

We attempt to treat the very early Universe according to quantum mechanics. Identifying the scale factor of the Universe with the width of the wave packet associated with it, we show that there cannot be an initial singularity and that the Universe expands. Invoking the correspondence principle, we obtain the scale factor of the Universe and demonstrate that the causality problem of the standard model is solved.

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