# Behavior of varying-alpha cosmologies

@article{Barrow2002BehaviorOV, title={Behavior of varying-alpha cosmologies}, author={John D. Barrow and H{\aa}vard Bunes Sandvik and Jo{\~a}o Magueijo}, journal={Physical Review D}, year={2002}, volume={65}, pages={063504} }

We determine the behaviour of a time-varying fine structure 'constant' $\alpha (t)$ during the early and late phases of universes dominated by the kinetic energy of changing $\alpha (t)$, radiation, dust, curvature, and lambda, respectively. We show that after leaving an initial vacuum-dominated phase during which $\alpha$ increases, $\alpha$ remains constant in universes like our own during the radiation era, and then increases slowly, proportional to a logarithm of cosmic time, during the… Expand

#### 95 Citations

Qualitative analysis of universes with varying alpha

- Physics
- 2002

Assuming a Friedmann universe which evolves with a power-law scale factor, a = t n, we analyse the phase space of the system of equations that describes a time-varying fine structure 'constant', α,… Expand

General Dynamics of Varying-Alpha Universes

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We introduce and study extensions of the varying alpha theory of Bekenstein-Sandvik-Barrow-Magueijo to allow for an arbitrary coupling function and self-interaction potential term in the theory. We… Expand

Constants and Variations: From Alpha to Omega

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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… Expand

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Using a gauge-invariant formalism we derive and solve the perturbed cosmological equations for the BSBM theory of varying fine structure 'constant'. We calculate the time evolution of inhomogeneous… Expand

Constants and Variations: From Alpha to Omega

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- 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… Expand

Evolution of the fine structure constant driven by dark matter and the cosmological constant

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Bekenstein's model of a scalar field $\ensuremath{\varphi}$ that affects the electromagnetic permeability (usually identified with ``changing $\ensuremath{\alpha}'')$ predicts tiny variations of the… Expand

Variations of the Fine Structure Constant in Space and Time

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- 2006

This thesis describes a detailed investigation of the effects of matter inhomogeneities on the cosmological evolution of the fine structure constant using the Bekenstein-Sandvik-Barrow-Magueijo… Expand

Dark energy and Equivalence Principle constraints from astrophysical tests of the stability of the fine-structure constant

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Astrophysical tests of the stability of fundamental couplings, such as the fine-structure constant $\alpha$, are becoming an increasingly powerful probe of new physics. Here we discuss how these… Expand

Time variation of the fine structure constant in the early universe and the Bekenstein model

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- 2008

Aims. We calculate the bounds on the variation in the fine structure constant at the time of primordial nucleosynthesis and at the time of neutral hydrogen formation. We used these bounds and other… Expand

Cosmological constants and variations

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We review properties of theories for the variation of the gravitation and fine structure 'constants'. We highlight some general features of the cosmological models that exist in these theories with… Expand

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