Quantum theory in external electromagnetic and gravitational fields: A comparison of some conceptual issues

Pramana ◽  
1991 ◽  
Vol 37 (3) ◽  
pp. 179-233 ◽  
Author(s):  
T Padmanabhan
Keyword(s):  
Quantum Theory ◽  
Gravitational Fields

Matvei Bronstein 1936, quantum theory of weak gravitational fields.

2012 ◽  
pp. 325-345
Author(s):  
Andrzej Krasiński ◽  
George F. R. Ellis ◽  
Malcolm A. H. MacCallum
Keyword(s):  
Quantum Theory ◽  
Gravitational Fields

scholarly journals Can We Detect the Quantum Nature of Weak Gravitational Fields?

Universe ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 414
Author(s):  
Francesco Coradeschi ◽  
Antonia Micol Frassino ◽  
Thiago Guerreiro ◽  
Jennifer Rittenhouse West ◽  
Enrico Junior Schioppa
Keyword(s):  
General Relativity ◽  
Quantum Theory ◽  
Quantum Gravity ◽  
Gravitational Wave ◽  
Experimental Evidence ◽  
Theoretical Framework ◽  
Holy Grail ◽  
Gravitational Fields ◽  
Quantum Nature ◽  
Quantization Of Gravity

A theoretical framework for the quantization of gravity has been an elusive Holy Grail since the birth of quantum theory and general relativity. While generations of scientists have attempted to find solutions to this deep riddle, an alternative path built upon the idea that experimental evidence could determine whether gravity is quantized has been decades in the making. The possibility of an experimental answer to the question of the quantization of gravity is of renewed interest in the era of gravitational wave detectors. We review and investigate an important subset of phenomenological quantum gravity, detecting quantum signatures of weak gravitational fields in table-top experiments and interferometers.

Einstein, Albert (1879–1955)

2018 ◽  
Author(s):  
Arthur Fine ◽  
Don Howard ◽  
John D. Norton
Keyword(s):  
Quantum Theory ◽  
Albert Einstein ◽  
Later Life ◽  
Special Theory ◽  
Theoretical Concepts ◽  
Gravitational Fields ◽  
Prominent Scientist ◽  
Dimensional Spacetime ◽  
Theory Of Gravitation ◽  
Geometric Formulation

Albert Einstein was a German-born Swiss and American naturalized physicist and the twentieth century’s most prominent scientist. He produced the special and general theories of relativity, which overturned the classical understanding of space, time and gravitation. According to the special theory (1905), uniformly moving observers with different velocities measure the same speed for light. From this he deduced that the length of a system shrinks and its clocks slow at speeds approaching that of light. The general theory (completed 1915) proceeds from Hermann Minkowski’s geometric formulation of special relativity as a four-dimensional spacetime. Einstein’s theory allows, however, that the geometry of spacetime may vary from place to place. This variable geometry or curvature is associated with the presence of gravitational fields. Acting through geometrical curvature, these fields can slow clocks and bend light rays. Einstein made many fundamental contributions to statistical mechanics and quantum theory, including the demonstration of the atomic character of matter and the proposal that light energy is organized in spatially discrete light quanta. In later life, he searched for a unified theory of gravitation and electromagnetism as an alternative to the quantum theory developed in the 1920s. He complained resolutely that this new quantum theory was not complete. Einstein’s writings in philosophy of science developed a conventionalist position, stressing our freedom to construct theoretical concepts; his later writings emphasized his realist tendencies and the heuristic value of the search for mathematically simple laws.

scholarly journals Is the Wheeler–DeWitt equation more fundamental than the Schrödinger equation?

2018 ◽  
Vol 27 (06) ◽  
pp. 1841004 ◽  
Author(s):  
Tatyana P. Shestakova
Keyword(s):  
Quantum Theory ◽  
Schrödinger Equation ◽  
Schrodinger Equation ◽  
Degrees Of Freedom ◽  
Symmetric Model ◽  
Extended Phase ◽  
Gravitational Fields ◽  
Quantization Of Gravity ◽  
Theory Of Gravity ◽  
Spherically Symmetric Model

The Wheeler–DeWitt equation was proposed 50 years ago and until now it is the cornerstone of most approaches to quantization of gravity. One can find in the literature, the opinion that the Wheeler–DeWitt equation is even more fundamental than the basic equation of quantum theory, the Schrödinger equation. We still should remember that we are in the situation when no observational data can confirm or reject the fundamental status of the Wheeler–DeWitt equation, so we can give just indirect arguments in favor of or against it, grounded on mathematical consistency and physical relevance. I shall present the analysis of the situation and comparison of the standard Wheeler–DeWitt approach with the extended phase space approach to quantization of gravity. In my analysis, I suppose, first, that a future quantum theory of gravity must be applicable to all phenomena from the early universe to quantum effects in strong gravitational fields, in the latter case, the state of the observer (the choice of a reference frame) may appear to be significant. Second, I suppose that the equation for the wave function of the universe must not be postulated but derived by means of a mathematically consistent procedure, which exists in path integral quantization. When applying this procedure to any gravitating system, one should take into account features of gravity, namely, nontrivial spacetime topology and possible absence of asymptotic states. The Schrödinger equation has been derived early for cosmological models with a finite number of degrees of freedom, and just recently it has been found for the spherically symmetric model which is a simplest model with an infinite number of degrees of freedom. The structure of the Schrödinger equation and its general solution appears to be very similar in these cases. The obtained results give grounds to say that the Schrödinger equation retains its fundamental meaning in constructing quantum theory of gravity.

Consistent Quantum Theory

2001 ◽  
Author(s):  
Robert B. Griffiths
Keyword(s):  
Quantum Theory

Quantum theory of light in nonlinear media with dispersion and absorption

1998 ◽  
Vol 45 (2) ◽  
pp. 377-402 ◽  
Author(s):  
EDUARD SCHMIDT , JOHN JEFFERS , STEPHEN M.
Keyword(s):  
Quantum Theory ◽  
Nonlinear Media
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