scholarly journals Measuring quantum gravity

2018 ◽  
Vol 96 (4) ◽  
pp. 366-378
Author(s):  
Arundhati Dasgupta
Keyword(s):  
General Relativity ◽  
Quantum Theory ◽  
General Theory ◽  
Quantum Gravity ◽  
Gravity Waves ◽  
Experimental Tests ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Theory Of Gravity

Einstein’s theory of gravity, known as the general theory of relativity was established in 1915. The theory has survived many experimental tests, and the recent discovery of gravity waves announced in 2016 confirms yet another success. In this article we examine some results from quantum general relativity, and ask whether the new quantum theory can survive tests in the same way as its classical origins.

Einstein’s General Theory of Relativity and the Development of Modified Theories of Gravitation

2020 ◽  
Vol 29 (11) ◽  
pp. 2-9
Author(s):  
Bogeun GWAK, ◽  
Bum-Hoon LEE ◽  
Wonwoo LEE
Keyword(s):  
General Relativity ◽  
Dark Matter ◽  
Dark Energy ◽  
General Theory ◽  
Quantum Gravity ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Theory Of Gravitation ◽  
Wave Dark Matter ◽  
Theories Of Gravitation

We briefly review both Einstein’s general theory of relativity and the development of modified theories of gravitation with theoretical and observational motivations. For this, we discuss the theoretical properties and weaknesses of general relativity. We also mention attempts that have been made to develop the theory of quantum gravity. The recent detections of a gravitational wave, dark matter, and dark energy have opened new windows into astrophysics, as well as cosmology, through which tests to determine the theory of gravitation that best describes our Universe would be interesting. Most of all, note that we cannot clearly describe our Universe, including dark matter and dark energy, with standard particle models and the general theory of relativity. In these respects, we must be open-minded and study all possible aspects.

Albert Einstein’s Epistemic Virtues and Vices

2021 ◽  
Vol 58 (4) ◽  
pp. 175-195
Author(s):  
Vladimir P. Vizgin ◽  
Keyword(s):  
Field Theory ◽  
General Relativity ◽  
General Theory ◽  
Special Theory ◽  
Theory Of Relativity ◽  
Mathematical Aspect ◽  
General Theory Of Relativity ◽  
Special Theory Of Relativity ◽  
Epistemic Virtues ◽  
The Universe

The article is based on the concepts of epistemic virtues and epistemic vices and explores A. Einstein’s contribution to the creation of fundamental physical theories, namely the special theory of relativity and general theory of relativity, as well as to the development of a unified field theory on the basis of the geometric field program, which never led to success. Among the main epistemic virtues that led Einstein to success in the construction of the special theory of relativity are the following: a unique physical intuition based on the method of thought experiment and the need for an experimental justification of space-time concepts; striving for simplicity and elegance of theory; scientific courage, rebelliousness, signifying the readiness to engage in confrontation with scientific conventional dogmas and authorities. In the creation of general theory of relativity, another intellectual virtue was added to these virtues: the belief in the heuristic power of the mathematical aspect of physics. At the same time, he had to overcome his initial underestimation of the H. Minkowski’s four-dimensional concept of space and time, which has manifested in a distinctive flexibility of thinking typical for Einstein in his early years. The creative role of Einstein’s mistakes on the way to general relativity was emphasized. These mistakes were mostly related to the difficulties of harmonizing the mathematical and physical aspects of theory, less so to epistemic vices. The ambivalence of the concept of epistemic virtues, which can be transformed into epistemic vices, is noted. This transformation happened in the second half of Einstein’s life, when he for more than thirty years unsuccessfully tried to build a unified geometric field theory and to find an alternative to quantum mechanics with their probabilistic and Copenhagen interpretation In this case, we can talk about the following epistemic vices: the revaluation of mathematical aspect and underestimation of experimentally – empirical aspect of the theory; adopting the concepts general relativity is based on (continualism, classical causality, geometric nature of fundamental interactions) as fundamental; unprecedented persistence in defending the GFP (geometrical field program), despite its failures, and a certain loss of the flexibility of thinking. A cosmological history that is associated both with the application of GTR (general theory of relativity) to the structure of the Universe, and with the missed possibility of discovering the theory of the expanding Universe is intermediate in relation to Einstein’s epistemic virtues and vices. This opportunity was realized by A.A. Friedmann, who defeated Einstein in the dispute about if the Universe was stationary or nonstationary. In this dispute some of Einstein’s vices were revealed, which Friedman did not have. The connection between epistemic virtues and the methodological principles of physics and also with the “fallibilist” concept of scientific knowledge development has been noted.

scholarly journals Prediction for the cosmological constant and constraints on SUSY GUTs in resummed quantum gravity

2018 ◽  
Vol 33 (29) ◽  
pp. 1830028
Author(s):  
B. F. L. Ward
Keyword(s):  
General Theory ◽  
Quantum Gravity ◽  
Cosmological Constant ◽  
Uncertainty Principle ◽  
Planck Scale ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Heisenberg Uncertainty Principle ◽  
Heisenberg Uncertainty

Working in the context of the Planck scale cosmology formulation of Bonanno and Reuter, we use our resummed quantum gravity approach to Einstein’s general theory of relativity to estimate the value of the cosmological constant as [Formula: see text]. We show that SUSY GUT models are constrained by the closeness of this estimate to experiment. We also address various consistency checks on the calculation. In particular, we use the Heisenberg uncertainty principle to remove a large part of the remaining uncertainty in our estimate of [Formula: see text].

The mechanics of general relativity

1959 ◽  
Vol 251 (1264) ◽  
pp. 55-65 ◽  
Keyword(s):  
General Relativity ◽  
General Theory ◽  
Equations Of Motion ◽  
Stress Singularity ◽  
Theory Of Relativity ◽  
General Theory Of Relativity

It is shown how to obtain, within the general theory of relativity, equations of motion for two oscillating masses at the ends of a spring of given law of force. The method of Einstein, Infeld & Hoffmann is used, and the force in the spring is represented by a stress singularity. The detailed calculations are taken to the Newtonian order.

scholarly journals Fine Structure Constant derived from Principle Theory.

2021 ◽  
Author(s):  
Manfred Geilhaupt
Keyword(s):  
General Relativity ◽  
Fine Structure ◽  
General Theory ◽  
Rest Mass ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
The Standard Model ◽  
Principle Theory

Abstract Derivation of mass (m), charge (e) and fine structure constant (FSC) from theory are unsolved problems in physics up to now. Neither the Standard Model (SM) nor the General theory of Relativity (GR) has provided a complete explanation for mass, charge and FSC. The question “of what is rest mass” is therefore still essentially unanswered. We will show that the combination of two Principle Theories, General Relativity and Thermodynamics (TD), is able to derive the restmass of an electron (m) which surprisingly depends on the (Sommerfeld) FSC (same for the charge (e)).

scholarly journals Wormhole modeling in R2 gravity with linear trace term

2020 ◽  
Vol 35 (08) ◽  
pp. 2050045
Author(s):  
Nisha Godani ◽  
Gauranga C. Samanta
Keyword(s):  
General Relativity ◽  
General Theory ◽  
Significant Contribution ◽  
Shape Function ◽  
Exotic Matter ◽  
Geometric Configuration ◽  
Energy Conditions ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Traversable Wormholes

Morris and Thorne1 proposed traversable wormholes, hypothetical connecting tools, using the concept of Einstein’s general theory of relativity. In this paper, the modification of general relativity (in particular [Formula: see text] theory of gravity defined by Harko et al.2) is considered, to study the traversable wormhole solutions. The function [Formula: see text] is considered as [Formula: see text], where [Formula: see text] and [Formula: see text] are controlling parameters. The shape and redshift functions appearing in the metric of wormhole structure have significant contribution in the development of wormhole solutions. We have considered both variable and constant redshift functions with a logarithmic shape function. The energy conditions are examined, geometric configuration is analyzed and the radius of the throat is determined in order to have wormhole solutions in absence of exotic matter.

scholarly journals Relativistic redshift of the star S0-2 orbiting the Galactic Center supermassive black hole

Science ◽  
2019 ◽  
Vol 365 (6454) ◽  
pp. 664-668 ◽  
Author(s):  
Tuan Do ◽  
Aurelien Hees ◽  
Andrea Ghez ◽  
Gregory D. Martinez ◽  
Devin S. Chu ◽  
...  
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
General Theory ◽  
Galactic Center ◽  
Statistical Significance ◽  
Gravitational Redshift ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Supermassive Black Hole ◽  
Newtonian Model

The general theory of relativity predicts that a star passing close to a supermassive black hole should exhibit a relativistic redshift. In this study, we used observations of the Galactic Center star S0-2 to test this prediction. We combined existing spectroscopic and astrometric measurements from 1995–2017, which cover S0-2’s 16-year orbit, with measurements from March to September 2018, which cover three events during S0-2’s closest approach to the black hole. We detected a combination of special relativistic and gravitational redshift, quantified using the redshift parameter ϒ. Our result, ϒ = 0.88 ± 0.17, is consistent with general relativity (ϒ = 1) and excludes a Newtonian model (ϒ = 0) with a statistical significance of 5σ.

A NEW EXTENSION OF GENERAL RELATIVISTIC THEORY

1994 ◽  
Vol 03 (02) ◽  
pp. 393-419 ◽  
Author(s):  
MASATOSHI YAZAKI
Keyword(s):  
General Relativity ◽  
General Theory ◽  
Relativistic Theory ◽  
Maxwell's Equations ◽  
Geometrical Structure ◽  
Finsler Geometry ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
General Relativistic ◽  
Einstein’S General Relativity

The possibility of a new extension of the general relativistc theory will be considered using Finsler geometry. The extension of Einstein’s general relativity can be expected to regard gravitational, electroweak, and strong interactive fields as geometrical structure of a spacetime based on Finsler geometry. Indeed, it will be shown that this theory can include the general theory of relativity under a certain special condition. In addition, Maxwell’s equations will be expressed using new metric representations of the electromagnetic vector and its tensor. Moreover, it will be suggested that this theory may include metric representations of weak and strong interactive fields.

scholarly journals GENERAL RELATIVITY AND WEYL FRAMES

2011 ◽  
Vol 03 ◽  
pp. 27-35
Author(s):  
C. ROMERO ◽  
J. B. FONSECA-NETO ◽  
M. L. PUCHEU
Keyword(s):  
General Relativity ◽  
General Theory ◽  
Riemannian Geometry ◽  
Vacuum Solution ◽  
Gravitational Theory ◽  
Mathematical Formalism ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Weyl Geometry ◽  
Starting Point

We present the general theory of relativity in the language of a non-Riemannian geometry, namely, Weyl geometry. We show that the new mathematical formalism may lead to different pictures of the same gravitational phenomena, by making use of the concept of Weyl frames. We show that, in this formalism, it is possible to construct a scalar-tensor gravitational theory that is invariant with respect to the so-called Weyl tranformations and reduces to general relativity in a particular frame, the Riemann frame. In this approach the Weyl geometry plays a fundamental role since it appears as the natural geometrical setting of the theory when viewed in an arbitrary frame. Our starting point is to build an action that is manifestly invariant with respect to Weyl transformations. When this action is expressed in more familiar terms of Riemannian geometry we find that the theory has some similarities with Brans-Dicke theory of gravity. We illustrate this point with an example in which a known Brans-Dicke vacuum solution may appear when reinterpreted in a particular Weyl frame.

The Lens of Gravity

2018 ◽  
Author(s):  
David D. Nolte
Keyword(s):  
Twentieth Century ◽  
General Relativity ◽  
General Theory ◽  
Solar Eclipse ◽  
History Of Physics ◽  
Space Time ◽  
Paradigm Shifts ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
History Of

This chapter describes how gravity provided the backdrop for one of the most important paradigm shifts in the history of physics. Prior to Albert Einstein’s general theory of relativity, trajectories were paths described by geometry. After the theory of general relativity, trajectories are paths caused by geometry. This chapter explains how Einstein arrived at his theory of gravity, relying on the space-time geometry of Hermann Minkowski, whose work he had originally harshly criticized. The confirmation of Einstein’s theory was one of the dramatic high points in twentieth-century history of physics when Arthur Eddington journeyed to an island off the coast of Africa to observe stellar deflections during a solar eclipse. If Galileo was the first rock star of physics, then Einstein was the first worldwide rock star of science.

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