New varying speed of light theories

By João Magueijo. 2003

274 citations recorded by the source corpus.

We review recent work on the possibility of a varying speed of light (VSL). We start by discussing the physical meaning of a varying-c, dispelling the myth that the constancy of c is a matter of logical consistency. We then summarize the main VSL mechanisms proposed so far: hard breaking of Lorentz invariance; bimetric theories (where the speeds of gravity and light are not the same); locally Lorentz invariant VSL theories; theories exhibiting a colour-dependent speed of light; varying-c induced by extra dimensions (e.g. in the brane-world scenario); and field theories where VSL results from vacuum polarization or CPT violation. We show how VSL scenarios may solve the cosmological problems usually tackled by inflation, and also how they may produce a scale-invariant spectrum of Gaussian fluctuations, capable of explaining the WMAP data. We then review the connection between VSL and theories of quantum gravity, showing how 'doubly special' relativity has emerged as a VSL effective model of quantum space?time, with observational implications for ultra-high energy cosmic rays (UHECRs) and gamma ray bursts. Some recent work on the physics of 'black' holes and other compact objects in VSL theories is also described, highlighting phenomena associated with spatial (as opposed to temporal) variations in c. Finally, we describe the observational status of the theory. The evidence is currently slim?redshift dependence in the atomic fine structure, anomalies with UHECRs, and (to a much lesser extent) the acceleration of the universe and the WMAP data. The constraints (e.g. those arising from nucleosynthesis or geological bounds) are tight but not insurmountable. We conclude with the observational predictions of the theory and the prospects for its refutation or vindication.

Subfields: Astronomy and Astrophysics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/8d738fa38b22f01df90cde35c2129d93d34ab71e

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In Astronomy and Astrophysics

In Statistical and Nonlinear Physics

Citations in the corpus

The Confrontation between General Relativity and Experiment (2005, background): “Another class of non-metric theories are included in the “varying speed of light (VSL)” theories; for a detailed review, see [178].”
c is the speed of light, isn’t it? (2003, unknown): “[50] J. Magueijo (2003), [astro-ph/0305457].”
Lorentz violation at high energy: Concepts, phenomena, and astrophysical constraints (2005, background): “A set of related ideas goes under the generic name of “varying speed of light cosmologies” (VSL), which includes numerous distinct formulations [18,19].”
Modern Tests of Lorentz Invariance (2005, methodology): “Further information on copyright is given at http://relativity.livingreviews.org/About/copyright.html For permission to reproduce the article please contact livrev@aei.mpg.de.”
Constraints on black-hole charges with the 2017 EHT observations of M87* (2021, background): “As a result, the electromagnetic Lagrangian in all of the theories considered here is the Maxwell Lagrangian (see, e.g., the discussion in [15] and compare with [20]).”
Quantum-Spacetime Phenomenology (2008, background): “[385], this alternative to inflation is rather severely constrained but still to be considered a viable alternative to inflation.”