Heuristics of String Theory

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The logical positivists would have considered string theory as a speculative metaphysics. The instrumentalist aspect of logical positivism does not correspond with the opinions of string theorists. From the point of view of Popper’s falsifiability, [1] we clearly distinguish between … Read More

Epistemology of String Theory in Quantum Gravity

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In quantum field theory, the main obstacle is the occurrence of the untreatable infinities in the interactions of the particles due to the possibility of arbitrary distances between the point particles. Strings, as extended objects, provide a better framework, which … Read More

Epistemology of Canonical Quantum Gravity – Loop Quantum Gravity

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In the interpretation of canonical quantum gravity (CQG), gravity appears as a geometric pseudoforce, is reduced to spacetime geometry and becomes a simple effect of spacetime curvature. [1] (Maudlin[2]). Lehmkuhl[3] argues that canonical formalism does not confirm this interpretation. General … Read More

Heuristics and Tests of Quantum Gravity

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Heuristics of quantum gravity For the attempt to create a gravitational quantum theory, there are several research programs, some of which became obsolete over time due to the higher heuristic power of other programs. J. Butterfield thus distinguishes three major … Read More

Epistemology of Quantum Gravity

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Recent decades indicate “a blurring of distinction between physical science and mathematical abstraction … [reflecting] a growing tendency to accept, and in some cases ignore, serious testability problems.” [1] Oldershaw lists dozens of major non-testing issues in the pre-instrumentalist era. … Read More

Anomalies of General Relativity

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Over time, the general theory of relativity has accumulated several anomalies and discrepancies, indicating the need for a better theory about gravity or other approaches: Stars in galaxies have a distribution of increasing speeds from the center to the periphery, … Read More

Cosmological Tests of Gravity

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The current cosmological models are built based on general relativity. The solutions of the specific equations, Friedmann-Lemaître-Robertson-Walker, [1] allow to model the evolution of the universe starting from the Big Bang.[2] Some of the parameters of the universe have been … Read More

Strong Field Gravitational Tests

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When the density of the body becomes large enough, general relativity predicts the formation of a black hole. The neutron stars of about 1.4 solar masses and the black holes are the final stage for the evolution of the massive … Read More

Modern Tests of Relativistic Gravitational Theories

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Dicke and Schiff established a framework for testing general relativity, [1] including through null experiments and using the physics of space exploration, electronics and condensed matter, such as the Pound-Rebka experiment and laser interferometry. The gravitational lens tests and the … Read More

Classic gravitational tests of post-Einsteinian theories

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With the help of PPN formalism, gravity theories are confronted with the results of experiments in the solar system. The γ parameter in this formalism highlights the light deflection and the light delay. By calculations according to PPN, light deflection … Read More

Testing the relativistic theories of gravity

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Clifford M. Will describes, in Theory and Experiment in Gravitational Physics, [1] the emergence of a new era for general relativity, testing and checking at very high levels of accuracy. In 1959, scientists at Lincoln Laboratories in Massachusetts bombarded the … Read More

Evaluation of post-Einsteinian gravitational theories through parameterized post-Newtonian formalism

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Proliferation of post-Einsteinian gravitational theories Right after the elaboration and success of general relativity (GR), alternative theories for gravity began to appear, which can fall into four broad categories: [1] Bifurcated theories (with the Lakatosian[2] hard core identical or very … Read More

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