<i>The Theoretical Significance of Experimental Relativity</i>

Dicke, R. H.; Malamud, Herbert

doi:10.1063/1.3047551

Cited by 45 publications

(21 citation statements)

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“…Because the solution (23) should describe light emitted by our atom we require that at the time of emission it behave as exp(ik 0 η), where k 0 is any of the frequencies in eq. (19). Under the assumption of slowly varying B F this condition fixes the length of the wave vector k, ω em ≡ ω k (η em ) ≈ k 0 (η em ).…”

Section: Atomic Spectramentioning

confidence: 99%

“…Then, the atomic clock frequencies ω clock are still given by eq. (19), but the different factors have to be evaluated at the time of observation, ω clock = k 0 (η arr ). The observer determines the ratio of the frequency of the incoming photon to the frequency of the photon emitted by the clock to be…”

Section: Atomic Spectramentioning

confidence: 99%

“…Our derivation is rather to be regarded as a conservative attempt to delimit a basic, but still quite general reasonable set of theories to focus on. In fact, the action (8) is general enough to accommodate scalar-tensor theories of gravity [3], Bekenstein's theory of varying α and its revivals [4,19], and even the longwavelength limit of bimetric theories [5]. Finally, let us point out that the arguably only known "ultraviolet-complete" theory of quantum gravity, string theory, is expected to have an action of the form (8) as its low-energy limit [8].…”

Section: The Low Energy Effective Actionmentioning

confidence: 99%

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Predictions and observations in theories with varying couplings

Armendariz-Picon

2002

Phys. Rev. D

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We consider a toy universe containing conventional matter and an additional real scalar field, and discuss how the requirements of gauge and diffeomorphism invariance essentially single out a particular set of theories which might describe such a world at low energies. In these theories, fermion masses and g-factors, as well as the electromagnetic coupling turn to be scalar field dependent; fermion charges and the gravitational coupling might be assumed to be constant. We then proceed to study the impact of a time variation of the scalar field on measurements of atomic spectra at high redshifts. Light propagation is not affected by a sufficiently slow change of the fine structure constant, but changes of the latter as well as variations of fermion masses and g-factors do affect the observed atomic spectra. Finally, we prove the independence of these predictions on the chosen conformal frame, in a further attempt to address differing views about the subject expressed in the literature. * Electronic address: armen@oddjob.uchicago.edu

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Section: Atomic Spectramentioning

confidence: 99%

Section: Atomic Spectramentioning

confidence: 99%

Section: The Low Energy Effective Actionmentioning

confidence: 99%

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Predictions and observations in theories with varying couplings

Armendariz-Picon

2002

Phys. Rev. D

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“…Among the existing theories, the ensuing field equations of general relativity (GR) are perhaps the simplest. Since in GR, torsion, the antisymmetric combination of connection coefficients is identically zero, and since GR has withstood numerous precise experimental tests [1,2], introduction of torsion has seemed superfluous except in the presence of matter with intrinsic spin as in Einstein-Cartan formulations [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Metric theory of gravity with torsion in an extra dimension

2012

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We consider a theory of gravity with a hidden extra-dimension and metric-dependent torsion. A set of physically motivated constraints are imposed on the geometry so that the torsion stays confined to the extra-dimension and the extra-dimension stays hidden at the level of four dimensional geodesic motion. At the kinematic level, the theory maps on to General Relativity, but the dynamical field equations that follow from the action principle deviate markedly from the standard Einstein equations. We study static spherically symmetric vacuum solutions and homogeneous-isotropic cosmological solutions that emerge from the field equations. In both cases, we find solutions of significant physical interest. Most notably, we find positive mass solutions with naked singularity that match the well known Schwarzschild solution at large distances but lack an event horizon. In the cosmological context, we find oscillatory scenario in contrast to the inevitable singular big bang of the standard cosmology.

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“…In 1961, the Brans-Dicke theory was formulated. In this formalism, an additional scalar field φ besides the metric tensor g µν and a dimensionless coupling constant ω were introduced in order to describe the gravitational interaction (Brans & Dicke 1961;Brans 1962;Brans & Dicke 1962;Dicke 1962;Dicke 1964). Brans-Dicke theory recovers the results of GR for large value of the coupling constant ω, that is for ω > 500.…”

Section: Introductionmentioning

confidence: 99%

Exact scalar-tensor cosmological solutions via Noether symmetry

Belinchón

Harkó

Mak

2016

Astrophys Space Sci

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In this paper, we investigate the Noether symmetries of a generalized scalar-tensor, Brans-Dicke type cosmological model, in which we consider explicit scalar field dependent couplings to the Ricci scalar, and to the scalar field kinetic energy, respectively. We also include the scalar field self-interaction potential into the gravitational action. From the condition of the vanishing of the Lie derivative of the gravitational cosmological Lagrangian with respect to a given vector field we obtain three cosmological solutions describing the time evolution of a spatially flat Friedman-RobertsonWalker Universe filled with a scalar field. The cosmological properties of the solutions are investigated in detail, and it is shown that they can describe a large variety of cosmological evolutions, including models that experience a smooth transition from a decelerating to an accelerating phase.

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The Theoretical Significance of Experimental Relativity

Cited by 45 publications

References 0 publications

Predictions and observations in theories with varying couplings

Predictions and observations in theories with varying couplings

Metric theory of gravity with torsion in an extra dimension

Exact scalar-tensor cosmological solutions via Noether symmetry

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