The spatially flat Friedmann equation for early rainbow universe

2015 ◽  
Vol 30 (31) ◽  
pp. 1550165
Author(s):  
Han Siong Ch’ng ◽  
Geri Gopir ◽  
Shahidan Radiman
Keyword(s):  
Early Universe ◽  
Quantum Cosmology ◽  
Gravitational Constant ◽  
Friedmann Equation ◽  
Late Time ◽  
Friedmann Equations ◽  
Bohm Interpretation ◽  
The One ◽  
Canonical Quantum ◽  
De Broglie Bohm

We derive the spatially flat rainbow-Friedmann equation from de Broglie–Bohm interpretation in canonical quantum cosmology. Our result shows that the spatially flat rainbow-Friedmann equations of early and late-time universe are having different forms. The spatially flat rainbow-Friedmann equation of early universe which is obtained in this paper is quite different from the one which was initially derived by Magueijo and Smolin [Class. Quantum Grav. 21, 1725 (2004)]. However, the spatially flat rainbow-Friedmann equation for late-time universe obtained in this paper is found to be the same as the one derived by Magueijo and Smolin (for the case [Formula: see text] and Newton’s gravitational constant [Formula: see text]. The new spatially flat rainbow-Friedmann equation obtained in this paper could provide an alternative way in understanding the evolution of the early rainbow universe.

QUANTUM COSMOLOGY: SUSY'S STAGE

2013 ◽  
Vol 22 (04) ◽  
pp. 1330006 ◽  
Author(s):  
PAULO VARGAS MONIZ
Keyword(s):  
Early Universe ◽  
Quantum Cosmology ◽  
Quantum Effects ◽  
The Other ◽  
Parallel Session ◽  
Other Hand ◽  
Recent Developments ◽  
The One

This report comprises two parts. On the one hand, I will, based on the talks at the CM4 parallel session "Quantum Cosmology and Quantum Effects in the Early Universe" which I chaired, point to interesting recent developments in quantum cosmology. On the other hand, some of the basics of supersymmetric quantum cosmology are briefly reviewed, pointing to promising lines of research to explore. I will start with the latter, finishing the report with the former.

scholarly journals Friedmann equations for deformed entropic gravity

2020 ◽  
Vol 29 (06) ◽  
pp. 2050042
Author(s):  
Salih Kibaroğlu ◽  
Mustafa Senay
Keyword(s):  
Early Universe ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Frw Universe ◽  
Friedmann Equations ◽  
Entropic Gravity ◽  
The One ◽  
Two Parameters ◽  
Friedmann Robertson Walker

In this study, we investigate the effects of the one- and two-parameters deformed systems on the Friedmann equations of the Friedmann–Robertson–Walker (FRW) universe by using the entropic gravity approach in the framework of the early universe era. We give simplified forms for the deformed Unruh temperature and Einstein field equations for three different deformed systems. Based on these compact equations, we derive the Friedmann equations with the effective gravitational and cosmological terms.

scholarly journals DE BROGLIE–BOHM INTERPRETATION FOR WAVE FUNCTION OF REISSNER–NORDSTRÖM–DE SITTER BLACK HOLE

2000 ◽  
Vol 15 (14) ◽  
pp. 2059-2075 ◽  
Author(s):  
MASAKATSU KENMOKU ◽  
HIROTO KUBOTANI ◽  
EIICHI TAKASUGI ◽  
YUKI YAMAZAKI
Keyword(s):  
Black Hole ◽  
Wave Function ◽  
Spherically Symmetric ◽  
De Sitter ◽  
Semiclassical Gravity ◽  
Symmetric Geometry ◽  
Bohm Interpretation ◽  
Canonical Quantum ◽  
Ordinary Quantum ◽  
De Broglie Bohm

We study the canonical quantum theory of the spherically symmetric geometry with the cosmological constant and the electromagnetic field. We obtain a solution of the Wheeler–DeWitt equation for the geometrical variables and investigate the wave function from a viewpoint of the de Broglie–Bohm interpretation of the ordinary quantum mechanics. The de Broglie–Bohm interpretation introduces deterministic rigid trajectories on the minisuperspace without any outside observers nor the collapse of the wave function. It is shown that the wave function does not only correspond to the classical Reissner–Nordström–de Sitter black hole in the semiclassical region, but it also represents quantum geometrical fluctuations near the black hole horizon and the cosmological one. The result suggests that the semiclassical gravity on which the Hawking radiation is based is broken near the horizons.

scholarly journals The asymptotic behavior of bouncing cosmological models in F(𝒢) gravity theory

2017 ◽  
Vol 14 (10) ◽  
pp. 1750148 ◽  
Author(s):  
Andrey N. Makarenko ◽  
Alexander N. Myagky
Keyword(s):  
Asymptotic Behavior ◽  
Early Universe ◽  
Asymptotic Expansions ◽  
Scale Factor ◽  
Cosmological Models ◽  
Gravity Theory ◽  
Late Time ◽  
Puiseux Series ◽  
Friedmann Equations

We reconstruct [Formula: see text] gravity theory with an exponential scale factor to realize the bouncing behavior in the early universe and examine the asymptotic behavior of late-time solutions in this model. We propose an approach for the construction of asymptotic expansions of solutions of the Friedmann equations on the basis of Puiseux series.

scholarly journals Creation of particles in a cyclic universe driven by loop quantum cosmology

2015 ◽  
Vol 24 (08) ◽  
pp. 1550062 ◽  
Author(s):  
Yaser Tavakoli ◽  
Júlio C. Fabris
Keyword(s):  
Scalar Field ◽  
Quantum Cosmology ◽  
Particle Production ◽  
Friedmann Equation ◽  
Big Bang ◽  
Loop Quantum Cosmology ◽  
Late Time ◽  
Background Density ◽  
The Future ◽  
The Universe

We consider an isotropic and homogeneous universe in loop quantum cosmology (LQC). We assume that the matter content of the universe is dominated by dust matter in early time and a phantom matter at late time which constitutes the dark energy component. The quantum gravity modifications to the Friedmann equation in this model indicate that the classical big bang singularity and the future big rip singularity are resolved and are replaced by quantum bounce. It turns out that the big bounce and recollapse in the herein model contribute to a cyclic scenario for the universe. We then study the quantum theory of a massive, nonminimally coupled scalar field undergoing cosmological evolution from primordial bounce towards the late time bounce. In particular, we solve the Klein–Gordon equation for the scalar field in the primordial and late time regions, in order to investigate particle production phenomena at late time. By computing the energy density of created particles at late time, we show that this density is negligible in comparison to the quantum background density at Planck era. This indicates that the effects of quantum particle production do not influence the future bounce.

Cosmology of the generalized model of LQG

2020 ◽  
Vol 35 (30) ◽  
pp. 2050247
Author(s):  
Surajit Chattopadhyay ◽  
Martiros Khurshudyan ◽  
K. Myrzakulov ◽  
Antonio Pasqua ◽  
Ratbay Myrzakulov
Keyword(s):  
Scalar Field ◽  
Quantum Cosmology ◽  
Friedmann Equation ◽  
Loop Quantum Cosmology ◽  
De Sitter ◽  
Complicated Case ◽  
Friedmann Equations ◽  
Cosmological Solutions ◽  
Text Model ◽  
Friedmann Robertson Walker

In this paper, we study the main cosmological properties of the classical Friedmann equations in the case of homogeneous and isotropic Friedmann–Robertson–Walker Universe and we also generalized the expression of the Friedmann equation in the case of Loop Quantum Cosmology (LQC). Considering the [Formula: see text]-model, we found the solutions of the equations considered for two particular cases, i.e. [Formula: see text] (i.e. the de Sitter solution) and [Formula: see text]. Moreover, we considered and studied two exact cosmological solutions of the [Formula: see text]-model, in particular the power-law and the exponential ones. Moreover, we also considered a third more complicated case and we derived the solution for an arbitrary function of the time [Formula: see text]. A scalar field description of the model is presented by constructing its self-interacting potential.

scholarly journals De Broglie–Bohm interpretation of a Hořava–Lifshitz quantum cosmology model

2018 ◽  
Vol 33 (02) ◽  
pp. 1850014 ◽  
Author(s):  
G. Oliveira-Neto ◽  
L. G. Martins ◽  
G. A. Monerat ◽  
E. V. Corrêa Silva
Keyword(s):  
Perfect Fluid ◽  
Quantum Cosmology ◽  
Scale Factor ◽  
Quantum Potential ◽  
Quantum Level ◽  
Strong Indication ◽  
Bohm Interpretation ◽  
De Broglie Bohm

In this paper, we consider the De Broglie–Bohm interpretation of a Hořava–Lifshitz quantum cosmology model in the presence of a radiation perfect fluid. We compute the Bohm’s trajectory for the scale factor and show that it never goes to zero. That result gives a strong indication that this model is free from singularities at the quantum level. We also compute the quantum potential. That quantity helps in understanding why the scale factor never vanishes.

scholarly journals Topology change in canonical quantum cosmology

1997 ◽  
Vol 56 (6) ◽  
pp. 3329-3340 ◽  
Author(s):  
Vitorio A. De Lorenci ◽  
Jéro⁁me Martin ◽  
Nelson Pinto-Neto ◽  
Ivano Damião Soares
Keyword(s):  
Quantum Cosmology ◽  
Topology Change ◽  
Canonical Quantum
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