Black Holes and Quantum Gravity

2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Aurélien Barrau

The search for a quantum theory of gravitation is considered one of the most important problems in theoretical physics. Might black holes provide a key? Researchers are beginning to think that the emergence of a true black hole astronomy based on the measurement of gravitational waves and radio interferometry could bring quantum gravity into the field of experimental or observational science.

2018 ◽  
Vol 191 ◽  
pp. 07003
Author(s):  
Xavier Calmet ◽  
Boris Latosh

We show that alongside the already observed gravitational waves, quantum gravity predicts the existence of two additional massive classical fields and thus two new massive waves. We set a limit on their masses using data from Eöt-Wash-like experiments. We point out that the existence of these new states is a model independent prediction of quantum gravity. We explain how these new classical fields could impact astrophysical processes and in particular the binary inspirals of black holes. We calculate the emission rate of these new states in binary inspirals astrophysical processes.


Author(s):  
S. A. Larin

We analyze the R + R2 model of quantum gravity where terms quadratic in the curvature tensor are added to the General Relativity action. This model was recently proved to be a self-consistent quantum theory of gravitation, being both renormalizable and unitary. The model can be made practically indistinguishable from General Relativity at astrophysical and cosmological scales by the proper choice of parameters.


2018 ◽  
Vol 191 ◽  
pp. 07002 ◽  
Author(s):  
S.A. Larin

We consider relativistic quantum gravity with the action including terms quadratic in the curvature tensor. This model is known to be renormalizable. We demonstrate that the model is also unitary. New expressions for the corresponding Lagrangian and the graviton propagator within dimensional regularization are derived. We argue that the considered model is the proper candidate for the fundamental quantum theory of gravitation.


2018 ◽  
Vol 33 (05) ◽  
pp. 1850028 ◽  
Author(s):  
S. A. Larin

Relativistic quantum gravity with the action including terms quadratic in the curvature tensor is analyzed. We derive new expressions for the corresponding Lagrangian and the graviton propagator within dimensional regularization. We argue that the considered model is a good candidate for the fundamental quantum theory of gravitation.


Universe ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 435
Author(s):  
Sergey A. Larin

We analyze the R+R2 model of quantum gravity where terms quadratic in the curvature tensor are added to the General Relativity action. This model was recently proved to be a self-consistent quantum theory of gravitation, being both renormalizable and unitary. The model can be made practically indistinguishable from General Relativity at astrophysical and cosmological scales by the proper choice of parameters.


2016 ◽  
Vol 25 (12) ◽  
pp. 1644025 ◽  
Author(s):  
Tanmay Vachaspati

Stars that are collapsing towards forming a black hole but appear frozen near their Schwarzschild horizon are termed “black stars”. The collision of two black stars leads to gravitational radiation during the merging phase followed by a delayed gamma ray burst during coalescence. The recent observation of gravitational waves by LIGO, followed by a possible gamma ray counterpart by Fermi, suggests that the source may have been a merger of two black stars with profound implications for quantum gravity and the nature of black holes.


2021 ◽  
Author(s):  
Rui feng Zheng ◽  
Jia ming Shi ◽  
Taotao Qiu

Abstract It is well known that primordial black hole (PBH) can be generated in inflation process of the early universe, especially when the inflaton field has some non-trivial features that could break the slow-roll condition. In this paper, we investigate a toy model of inflation with bumpy potential, which has one or several bumps. We found that potential with multi-bump can give rise to power spectra with multi peaks in small-scale region, which can in turn predict the generation of primordial black holes in various mass ranges. We also consider the two possibilities of PBH formation by spherical collapse and elliptical collapse. And discusses the scalar-induced gravitational waves (SIGWs) generated by the second-order scalar perturbations.


2002 ◽  
Vol 11 (10) ◽  
pp. 1537-1540 ◽  
Author(s):  
SAMIR D. MATHUR

The entropy and information puzzles arising from black holes cannot be resolved if quantum gravity effects remain confined to a microscopic scale. We use concrete computations in nonperturbative string theory to argue for three kinds of nonlocal effects that operate over macroscopic distances. These effects arise when we make a bound state of a large number of branes, and occur at the correct scale to resolve the paradoxes associated with black holes.


2021 ◽  
pp. 2150200
Author(s):  
Revaz Beradze ◽  
Merab Gogberashvili ◽  
Lasha Pantskhava

In this paper, a brief analysis of repeated and overlapped gamma-ray bursts, fast radio bursts and gravitational waves is done. These signals may not be emitted by isolated cataclysmic events and we suggest interpreting some of them within the impenetrable black hole model, as the radiation reflected and amplified by the black hole horizons.


Universe ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 25 ◽  
Author(s):  
Stanislav Alexeyev ◽  
Maxim Sendyuk

We discuss black hole type solutions and wormhole type ones in the effective gravity models. Such models appear during the attempts to construct the quantum theory of gravity. The mentioned solutions, being, mostly, the perturbative generalisations of well-known ones in general relativity, carry out additional set of parameters and, therefore could help, for example, in the studying of the last stages of Hawking evaporation, in extracting the possibilities for the experimental or observational search and in helping to constrain by astrophysical data.


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