`c' is the speed of light, isn't it?

Abstract

Theories proposing a varying speed of light have recently been widely promoted under the claim that they offer an alternative way of solving the standard cosmological problems. Recent observational hints that the fine structure constant may have varied during over cosmological scales also has given impetus to these models. In theoretical physics the speed of light, $c$, is hidden in almost all equations but with different facets that we try to distinguish. Together with a reminder on scalar-tensor theories of gravity, this sheds some light on these proposed varying speed of light theories.

14 pages, Latex

References in corpus (6)

• Limits on the time variation of the electromagnetic fine-structure constant in the low energy limit from absorption lines in the spectra of distant quasars
• New varying speed of light theories
• `c' is the speed of light, isn't it?
• Spherically symmetric spacetimes in massive gravity
• Variation of the speed of light due to non-minimal coupling between electromagnetism and gravity
• Comment on "Black holes constrain varying constants"

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