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.

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.

String inspired cosmological models through Lagrangian invariance

2020 ◽  
Vol 17 (06) ◽  
pp. 2050085
Author(s):  
José Antonio Belinchón ◽  
Danae Polychroni
Keyword(s):  
Perfect Fluid ◽  
Power Law ◽  
Matter Field ◽  
Scale Factor ◽  
Cosmological Models ◽  
De Sitter ◽  
Text Field ◽  
Duality Property ◽  
Constant Potential ◽  
Variable Potential

We study a string inspired cosmological with variable potential through the Lagrangian invariance method in order to determine the form of the potential. We have studied four cases by combining the different fields, that is, the dilaton [Formula: see text] the potential [Formula: see text] the [Formula: see text]-field and the matter field (a perfect fluid). In all the studied cases, we found that the potential can only take two possible forms: [Formula: see text] and [Formula: see text] where [Formula: see text] and [Formula: see text] are numerical constants. We conclude that when we take into account the Kalb–Ramond field, i.e. the [Formula: see text]-field, then it is only possible to get a constant potential, [Formula: see text] Nevertheless, if this field is not considered, then we get two possible solutions for the potential: [Formula: see text] and [Formula: see text] In all the cases, if the potential is constant, [Formula: see text] then we get a de Sitter like solution for the scale factor of the metric, [Formula: see text], which verifies the [Formula: see text]-duality property, while if the potential varies, then we get a power-law solution for the scale factor, [Formula: see text] [Formula: see text]

scholarly journals AN EARLY UNIVERSE MODEL WITH STIFF MATTER AND A COSMOLOGICAL CONSTANT

2011 ◽  
Vol 03 ◽  
pp. 254-265 ◽  
Author(s):  
G. OLIVEIRA-NETO ◽  
G. A. MONERAT ◽  
E. V. CORRÊA SILVA ◽  
C. NEVES ◽  
L. G. FERREIRA FILHO
Keyword(s):  
Cosmological Constant ◽  
Perfect Fluid ◽  
Scale Factor ◽  
Initial Singularity ◽  
Discrete Energy ◽  
Classical Level ◽  
Stiff Matter ◽  
Expectation Value ◽  
Variational Formalism ◽  
Friedmann Robertson Walker

In the present work, we study the quantum cosmology description of a Friedmann-Robertson-Walker model in the presence of a stiff matter perfect fluid and a negative cosmological constant. We work in the Schutz's variational formalism and the spatial sections have constant negative curvature. We quantize the model and obtain the appropriate Wheeler-DeWitt equation. In this model the states are bounded therefore we compute the discrete energy spectrum and the corresponding eigenfunctions. In the present work, we consider only the negative eigenvalues and their corresponding eigenfunctions. This choice implies that the energy density of the perfect fluid is negative. A stiff matter perfect fluid with this property produces a model with a bouncing solution, at the classical level, free from an initial singularity. After that, we use the eigenfunctions in order to construct wave packets and evaluate the time-dependent expectation value of the scale factor. We find that it oscillates between maximum and minimum values. Since the expectation value of the scale factor never vanishes, we confirm that this model is free from an initial singularity, also, at the quantum level.

QUANTUM POTENTIAL INTERPRETATION OF THE WHEELER-DeWITT EQUATION

1994 ◽  
Vol 09 (16) ◽  
pp. 1429-1443 ◽  
Author(s):  
TSUTOMU HORIGUCHI
Keyword(s):  
Quantum Cosmology ◽  
Canonical Formalism ◽  
Quantum Potential ◽  
Forbidden Region ◽  
Quantum Geometrodynamics

We apply Bohm’s quantum potential interpretation to quantum cosmology. We study closed, flat and open minisuperspace models by introducing “extended” Robertson-Walker time which exists not only in classically allowed region but also in classically forbidden region. It is shown that how the classical universe emerges from the quantum area. We also discuss briefly quantum potential interpretation of quantum geometrodynamics based on the Arnowitt-Deser-Misner canonical formalism.

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