scholarly journals Quantum gravity without vacuum dispersion

2017 ◽  
Vol 26 (10) ◽  
pp. 1750119 ◽  
Author(s):  
D. N. Coumbe
Keyword(s):  
Quantum Gravity ◽  
Quantum Correction ◽  
Functional Form ◽  
Geodesic Distance ◽  
Generalized Uncertainty Principle ◽  
Scale Transformation ◽  
Area Spectrum ◽  
Time Interval ◽  
Speed Of Light ◽  
Dynamical Triangulation

A generic prediction of quantum gravity is the vacuum dispersion of light, and hence that a photon’s speed depends on its energy. We present further numerical evidence for a scale-dependent speed of light in the causal dynamical triangulation (CDT) approach to quantum gravity. We show that the observed scale-dependent speed of light in CDT can be accounted for by a scale-dependent transformation of geodesic distance, whose specific functional form implies a discrete equidistant area spectrum. We make two nontrivial tests of the proposed scale transformation: a comparison with the leading-order quantum correction to the gravitational potential and a comparison with the generalized uncertainty principle. In both cases, we obtain the same functional form. However, contrary to the widespread prediction of vacuum dispersion in quantum gravity, numerous experiments have now definitively ruled out linear vacuum dispersion beyond Planckian energy scales [Formula: see text], and have even constrained quadratic dispersion at the level [Formula: see text]. Motivated by these experimental constraints, we seek to reconcile quantum gravity with the absence of vacuum dispersion. We point out that given a scale-dependent geodesic distance, a scale-dependent time interval becomes essential to maintaining an invariant speed of light. We show how a particular scale-dependent time interval allows a photon’s speed to remain independent of its energy.

scholarly journals Remarks on Remnants by Fermions’ Tunnelling from Black Strings

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Deyou Chen ◽  
Zhonghua Li
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Uncertainty Principle ◽  
Final Stage ◽  
Generalized Uncertainty Principle ◽  
Black Hole Evaporation ◽  
Quantum Numbers ◽  
Black Strings

Hawking’s calculation is unable to predict the final stage of the black hole evaporation. When effects of quantum gravity are taken into account, there is a minimal observable length. In this paper, we investigate fermions’ tunnelling from the charged and rotating black strings. With the influence of the generalized uncertainty principle, the Hawking temperatures are not only determined by the rings, but also affected by the quantum numbers of the emitted fermions. Quantum gravity corrections slow down the increases of the temperatures, which naturally leads to remnants left in the evaporation.

scholarly journals QUANTUM CORRECTIONS TO GRAVITY AND THEIR IMPLICATIONS FOR COSMOLOGY AND ASTROPHYSICS

2012 ◽  
Vol 14 ◽  
pp. 73-87 ◽  
Author(s):  
JULIO C. FABRIS ◽  
PAULO L. C. DE OLIVEIRA ◽  
DAVI C. RODRIGUES ◽  
ALAN M. VELASQUEZ-TORIBIO ◽  
ILYA L. SHAPIRO
Keyword(s):  
Cosmological Constant ◽  
Free Parameter ◽  
Quantum Correction ◽  
Functional Form ◽  
Quantum Corrections ◽  
Inflationary Cosmology ◽  
Gravitational Action ◽  
Higher Derivative ◽  
Hilbert Action

The quantum contributions to the gravitational action are relatively easy to calculate in the higher derivative sector of the theory. However, the applications to the post-inflationary cosmology and astrophysics require the corrections to the Einstein-Hilbert action and to the cosmological constant, and those we can not derive yet in a consistent and safe way. At the same time, if we assume that these quantum terms are covariant and that they have relevant magnitude, their functional form can be defined up to a single free parameter, which can be defined on the phenomenological basis. It turns out that the quantum correction may lead, in principle, to surprisingly strong and interesting effects in astrophysics and cosmology .

Quantum gravity effects on scalar particle tunneling from rotating BTZ black hole

2018 ◽  
Vol 33 (12) ◽  
pp. 1850070 ◽  
Author(s):  
I. Ablu Meitei ◽  
T. Ibungochouba Singh ◽  
S. Gayatri Devi ◽  
N. Premeshwari Devi ◽  
K. Yugindro Singh
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Generalized Uncertainty Principle ◽  
Scalar Particle ◽  
Mass Energy ◽  
Btz Black Hole ◽  
Logarithmic Term ◽  
Scalar Particles ◽  
Gravity Effects ◽  
Correction Terms

Tunneling of scalar particles across the event horizon of rotating BTZ black hole is investigated using the Generalized Uncertainty Principle to study the corrected Hawking temperature and entropy in the presence of quantum gravity effects. We have determined explicitly the various correction terms in the entropy of rotating BTZ black hole including the logarithmic term of the Bekenstein–Hawking entropy [Formula: see text], the inverse term of [Formula: see text] and terms with inverse powers of [Formula: see text], in terms of properties of the black hole and the emitted particles — mass, energy and angular momentum. In the presence of quantum gravity effects, for the emission of scalar particles, the Hawking radiation and thermodynamics of rotating BTZ black hole are observed to be related to the metric element, hence to the curvature of space–time.

Gravitational analysis of neutral regular black hole in Rastall gravity

2020 ◽  
Vol 35 (27) ◽  
pp. 2050225 ◽  
Author(s):  
Riasat Ali ◽  
Muhammad Asgher ◽  
M. F. Malik
Keyword(s):  
Black Hole ◽  
Wave Equation ◽  
Quantum Gravity ◽  
Generalized Uncertainty Principle ◽  
Gravity Effect ◽  
Tunneling Radiation ◽  
Regular Black Hole ◽  
Quantum Gravity Effect ◽  
Stability And Instability ◽  
The Stability

This paper is devoted to the tunneling radiation and quantum gravity effect on tunneling radiation of neutral regular black hole in Rastall gravity. We analyzed the tunneling radiation and Hawking temperature of neutral regular black hole by applying the Hamilton-Jacobi ansatz phenomenon. Lagrangian wave equation have been investigated by generalized uncertainty principle (GUP), using the WKB-approximation and calculated the tunneling rate as well as temperature. Furthermore, we analyzed the temperature of this neutral regular black hole in the presence of gravity. The stability and instability of neutral regular black hole are also analyzed.

scholarly journals Exotic fermionic fields and minimal length

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
J. M. Hoff da Silva ◽  
D. Beghetto ◽  
R. T. Cavalcanti ◽  
R. da Rocha
Keyword(s):  
Dirac Equation ◽  
Quantum Gravity ◽  
Dirac Operator ◽  
Uncertainty Principle ◽  
Generalized Uncertainty Principle ◽  
Minimal Length ◽  
Dynamical Equations ◽  
Spacetime Manifold ◽  
Fermionic Fields

Abstract We investigate the effective Dirac equation, corrected by merging two scenarios that are expected to emerge towards the quantum gravity scale. Namely, the existence of a minimal length, implemented by the generalized uncertainty principle, and exotic spinors, associated with any non-trivial topology equipping the spacetime manifold. We show that the free fermionic dynamical equations, within the context of a minimal length, just allow for trivial solutions, a feature that is not shared by dynamical equations for exotic spinors. In fact, in this coalescing setup, the exoticity is shown to prevent the Dirac operator to be injective, allowing the existence of non-trivial solutions.

scholarly journals Towards Thermodynamics with Generalized Uncertainty Principle

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Ahmed Farag Ali ◽  
Mohamed Moussa
Keyword(s):  
Quantum Gravity ◽  
Uncertainty Principle ◽  
Generalized Uncertainty Principle ◽  
Ideal Gas ◽  
Considerable Change ◽  
Heisenberg Uncertainty Principle ◽  
Ideal Gases ◽  
Quantum Gravity Effect ◽  
Photon Gas ◽  
Heisenberg Uncertainty

Various frameworks of quantum gravity predict a modification in the Heisenberg uncertainty principle to a so-called generalized uncertainty principle (GUP). Introducing quantum gravity effect makes a considerable change in the density of states inside the volume of the phase space which changes the statistical and thermodynamical properties of any physical system. In this paper we investigate the modification in thermodynamic properties of ideal gases and photon gas. The partition function is calculated and using it we calculated a considerable growth in the thermodynamical functions for these considered systems. The growth may happen due to an additional repulsive force between constitutes of gases which may be due to the existence of GUP, hence predicting a considerable increase in the entropy of the system. Besides, by applying GUP on an ideal gas in a trapped potential, it is found that GUP assumes a minimum measurable value of thermal wavelength of particles which agrees with discrete nature of the space that has been derived in previous studies from the GUP.

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