# Cosmology: Black holes constrain varying constants

@article{Davies2002CosmologyBH, title={Cosmology: Black holes constrain varying constants}, author={Paul C. W. Davies and Tamara M. Davis and C. Lineweaver}, journal={Nature}, year={2002}, volume={418}, pages={602-603} }

There is evidence to suggest that the fine-structure constant, α — a measure of the strength of the electromagnetic interaction between photons and electrons — is slowly increasing over cosmological timescales. As α = e2/[planck]c (where e is the electronic charge, [planck] is Planck's constant and c is the speed of light), this would call into question which of these fundamental quantities are truly constant. Here we consider black-hole thermodynamics as a test of which constants might…

## 47 Citations

Cosmology (communication arising): Do black holes constrain varying constants?

- PhysicsNature
- 2003

Tentative observations of shifted spectral lines in distant quasars have rekindled interest in Dirac's old idea that the fundamental 'constants' of physics may vary over time. Davies et al. have…

Varying fine structure constant and black-hole physics

- Physics
- 2003

Recent astrophysical observations suggest that the value of fine structure constant α = e2/c may be slowly increasing with time. This may be due to an increase of e or a decrease of c, or both. In…

c is the speed of light, isn’t it?

- Physics
- 2005

Theories for a varying speed of light have been proposed as an alternative way of solving several standard cosmological problems. Recent observational hints that the fine structure constant may have…

Constants and Variations: From Alpha to Omega

- Physics
- 2003

We review some of the history and properties of theories for the variation of the gravitation and fine structure ‘constants’. We highlight some general features of the cosmological models that exist…

Cosmology with relativistically varying physical constants

- Physics
- 2020

We have shown that the varying physical constant model is consistent with the recently published variational approach wherein Einstein equations are modified to include the variation of the speed of…

Varying Constants, Gravitation and Cosmology

- Physics, MedicineLiving reviews in relativity
- 2011

The relations between the constants, the tests of the local position invariance and of the universality of free fall are detailed, and the unification mechanisms and the relation between the variation of different constants are described.

Comment on Time-variation of Fundamental Constants 1 Black Holes and Varying Constants

The possible time variation of dimensionless fundamental constants of nature, such as the fine-structure constant α, is a legitimate subject of physical enquiry. are merely human constructs whose…

Matter non-conservation in the universe and dynamical dark energy

- Physics
- 2012

In an expanding universe, the vacuum energy density ρΛ is expected to be a dynamical quantity. In quantum field theory in curved spacetime, ρΛ should exhibit a slow evolution, determined by the…

Cosmology with Relativistically Varying Physical Constants

- Physics
- 2020

We have shown that the varying physical constant model is consistent with the recently published variational approach wherein Einstein equations are modified to include the variation of the speed of…

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