Quantum relativity: An essay

WORLD SCIENTIFIC eBooks, 2006

A brief history of quantum gravity is sketched. While familiarity with basic ideas and notions of contemporary physics is assumed, technicalities are kept to a minimum and use of equations is avoided. Rather, the emphasis is on providing a coherent picture of the evolution of ideas and the current status of the subject.

Iconic Research and Engineering Journals, 2019

Quantum gravity is a field of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics, and where quantum effects cannot be ignored, as almost compact astrophysical objects where gravity effects are strong. The current understanding of gravity is based on Albert Einstein's general theory of relativity, which is formulated within the framework of classical physics. On the other hand, the other three fundamental forces of physics are described within the framework of quantum mechanics and quantum field theory, radically different formalisms for describing physical phenomena. It is sometimes argued that a description of quantum gravity is necessary based on the fact that a classical system cannot be consistently coupled with a quantum system. Although a quantum theory of gravity may be necessary to reconcile general relativity with the principles of quantum mechanics, difficulties arise when applying the usual prescriptions of quantum field theory to the force of gravity via gravitational bosons. Indexed Terms-gravity, quantum, and general relativity.

A theory's equations are designed to model physical behavior that reflects the nature of physical reality. Einstein's nonlinear gravity equation is 'linearized' in the 'weak field limit' by ignoring nonlinear terms. This can be misinterpreted as affecting the nature of the field. Linearization is a mathematical artifice making equations easier to solve, having zero effect on the physical nature of the field itself. Thus it is false to say that the weak gravitational field is not self-interacting. Nor is the weak gravitational field based on mass; the field equation is based on mass density. These aspects of gravity are investigated by replacing curved space-time with mass density in flat space. A novel quantum gravity relation is derived and related to quantum mechanics.

The Routledge Companion to Philosophy of Physics, 2021

Although general relativity is a predictively successful theory, it treats matter as classical rather than as quantum. For this reason, it will have to be replaced by a more fundamental quantum theory of gravity. Attempts to formulate a quantum theory of gravity suggest that such a theory may have radical consequences for the nature, and indeed the fate, of spacetime. The present article articulates what this problem of spacetime is and traces it three approaches to quantum gravity taking general relativity as their vantage point: semi-classical gravity, causal set theory, and loop quantum gravity.

Springer Proceedings in Physics, 2014

The goal of this work is to contribute to the development of a background-independent, non-perturbative approach to quantization of the gravitational field based on the conformal and projective structures of space-time. But first I attempt to dissipate some mystifications about the meaning of quantization, and foster an ecumenical, non-competitive approach to the problem of quantum gravity (QG), stressing the search for relations between different approaches in any overlapping regions of validity. Then I discuss some problems raised by the approach we call unimodular conformal and projective relativity (UCPR).

2014

Our present concept about gravity is related with the mass and distance of the object. Still we are following the Newtonian concepts of gravity to measure the gravity of objects. Albert Einstein has made a great work on the concept of gravity, after Newton. But still we are trying to know more about gravity. According to me gravity is the property of energy. One must have to explain gravity on the basis of energy. I am agreeing that mass is also a form of energy. But I prefer to find gravity in accordance with the total energy of a system. Here I am making an attempt on this field. I am sure that I am on the right track. I am not placing any new equations here. I am using the existing equations in physics to find the gravity through my thoughts. The way which I am using these equations are may be strange. Sometimes I am thinking in reverse order, first I have found the gravity with the concept of energy. For that I am applying a constant ''A'' and I am getting the value of ''A'' from the last part of equations. Because the value of gravity is still with Newtonian concepts.

Philosophy of Science, 2001

I argue that all current research programs in quantum gravity conform to the 17th century hypothetico-deductive model of scientific inquiry, perhaps of necessity given the current state of technology. In so far as they do not recognize and advertise the shortcomings of the research method they use, they do a disservice to the integrity of science, for the method admits of far less certainty accruing to its products than one would be led to believe by the pronouncements of researchers in the area.

2020

A nonstandard viewpoint to quantum gravity is discussed. General relativity and quantum mechanics are to be related as two descriptions of the same, e.g. as Heisenberg's matrix mechanics and Schrödinger's wave mechanics merged in the contemporary quantum mechanics. From the viewpoint of general relativity one can search for that generalization of relativity implying the invariance "within-out of" of the same system.

Journal of Modern Physics, 2021

Quantum gravitational theory, based on the hypothesis of the absolute reference system, reveals the function of the effects of the gravitational field at the microscopic and macroscopic scale. The quantum nature of gravitational potential, and the dynamics and kinetic energy of photons and elementary particles under the influence of the gravitational field are studied, and a quantum interpretation of gravitational redshift is given. There is also a complete agreement of this quantum gravitational theory with the existing experimental data.

2015

Quantum gravity effects modify the Heisenberg's uncertainty principle to the generalized uncertainty principle (GUP). Earlier work showed that the GUP-induced corrections to the Schrödinger equation, when applied to a non-relativistic particle in a one-dimensional box, led to the quantization of length. Similarly, corrections to the Klein-Gordon and the Dirac equations, gave rise to length, area and volume quantizations. These results suggest a fundamental granular structure of space. This thesis investigates how spacetime curvature and gravity might influence this discreteness of space. In particular, by adding a weak background gravitational field to the above three quantum equations, it is shown that quantization of lengths, areas and volumes continue to hold. Although the nature of this new quantization is quite complex, under proper limits, it reduces to cases without gravity. These results indicate the universality of quantum gravity effects. I am thankful to my supervisor Dr. Saurya Das for his inspiring guidance, constructive criticism, friendly advice and academic as well as non-academic support throughout the research project. I would like to express my gratitude to my committee members Dr. Mark Walton and Dr. Kent Peacock for all the valuable suggestions and comments they provided. I would also like to thank my family and friends for their help and encouragement. v Contents List of Figures viii vi 3.6.1 Case 1 : Length quantization along x axis .