VARIABLE SPEED OF LIGHT THEORIES: A THERMODYNAMIC ANALYSIS OF PLANETARY AND WHITE DWARF PHENOMENA

2011 ◽  
Vol 20 (05) ◽  
pp. 805-820
Author(s):  
PABLO D. SISTERNA
Keyword(s):  
Scalar Field ◽  
Time Variation ◽  
Equations Of State ◽  
Structure Constant ◽  
Hydrostatic Equilibrium ◽  
Fine Structure Constant ◽  
Variable Speed ◽  
Speed Of Light ◽  
Modified Equations ◽  
Scalar Contribution

The thermodynamics of a scalar field interacting with a perfect fluid is studied, and observable consequences of the covariant variable speed of light (VSL) theory proposed by J. Magueijo are obtained. The first law of thermodyamics is modified as the scalar field becomes an additional thermodynamical variable. A recipe to obtain the modified equations of state is also obtained. After discussing the Newtonian limit and the non-relativistic hydrostatic equilibrium equation for the theory, the time-variation of the radius of Mercury induced by the variability of the speed of light (c), and the scalar contribution to the luminosity of white dwarfs are found. Using a bound for the change of that radius and combining it with an upper limit for the variation of the fine-structure constant, a bound on the time-variation of c is set. An independent bound is obtained from luminosity estimates for Stein 2015B.

BOUND ON THE TIME VARIATION OF THE FINE STRUCTURE CONSTANT DRIVEN BY QUINTESSENCE

2005 ◽  
Vol 14 (02) ◽  
pp. 335-343 ◽  
Author(s):  
DA-SHIN LEE ◽  
WOLUNG LEE ◽  
KIN-WANG NG
Keyword(s):  
Fine Structure ◽  
Scalar Field ◽  
Time Variation ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Fifth Force

The bound on the time variation of the fine structure constant (α) driven by the dynamics of quintessence scalar field which is coupled to electromagnetism is discussed using phenomenological quintessential models constrained by SNIa and CMB observations. We find that those models allowing early quintessence give the largest variation Δα at the decoupling epoch. Furthermore, the fifth force experiments imply that Δα/α is less than about 0.1%.

scholarly journals BIMETRIC GRAVITY THEORY, VARYING SPEED OF LIGHT AND THE DIMMING OF SUPERNOVAE

2003 ◽  
Vol 12 (02) ◽  
pp. 281-298 ◽  
Author(s):  
J. W. MOFFAT
Keyword(s):  
Scalar Field ◽  
Structure Constant ◽  
Friedmann Equation ◽  
Gravitational Theory ◽  
Fine Structure Constant ◽  
Speed Of Light ◽  
Dark Energy Component ◽  
Bimetric Gravity ◽  
Physical Consequences ◽  
The Universe

In the bimetric scalar–tensor gravitational theory there are two frames associated with the two metrics ĝμν and gμν, which are linked by the gradients of a scalar field ϕ. The choice of a comoving frame for the metric ĝμν or gμν has fundamental physical consequences for local observers in either metric spacetimes, while maintaining diffeomorphism invariance. If the metric gμν is chosen to be associated with comoving coordinates, then the speed of light varies in the frame with the metric ĝμν. Observers in this frame see the dimming of supernovae because of the increase of luminosity distance versus red shift, due to an increasing speed of light in the past universe. Moreover, in this frame the scalar field ϕ describes a dark energy component in the Friedmann equation for the cosmic scale without acceleration. If we choose ĝμν to be associated with comoving coordinates, then an observer in the gμν metric frame will observe the universe to be accelerating and the supernovae will appear to be farther away. The theory predicts that the gravitational constant G can vary in spacetime, while the fine-structure constant α = e2/ℏc does not vary. The problem of cosmological horizons as viewed in the two frames is discussed.

LIMIT ON THE TIME VARIATION OF THE FINE STRUCTURE CONSTANT DRIVEN BY QUINTESSENCE

2004 ◽  
Vol 19 (13n16) ◽  
pp. 1089-1092 ◽  
Author(s):  
WOLUNG LEE ◽  
KIN-WANG NG ◽  
DA-SHIN LEE
Keyword(s):  
Fine Structure ◽  
Dark Energy ◽  
Scalar Field ◽  
Time Variation ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Fifth Force

We study the time variation of the fine structure constant driven by quintessential dark energy which is coupled to electromagnetism. By employing phenomenological quintessential models which provide the scalar field with maximal dynamics and satisfy the constraints from SNIa observations and the WMAP, we show that the fifth force experiments restrict the variation of the value of α at the decoupling epoch with respect to the present-day value from being less than about 0.1%.

A FIVE DIMENSIONAL MODEL OF EFFECTIVE GRAVITATIONAL AND FINE-STRUCTURE CONSTANTS

2002 ◽  
Vol 17 (29) ◽  
pp. 4317-4323 ◽  
Author(s):  
J. P. MBELEK ◽  
M. LACHIÈZE-REY
Keyword(s):  
Fine Structure ◽  
Scalar Field ◽  
Gravitational Constant ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Five Dimensional Model ◽  
Bulk Scalar Field ◽  
Structure Constants ◽  
Good Agreement ◽  
Kaluza Klein

It is shown that the coupling of the Kaluza-Klein (KK) internal scalar field both to an external stabilizing bulk scalar field and to the geomagnetic field may explain the observed dispersion in laboratory measurements of the (effective) gravitational constant. Except the PTB 95 value, the predictions are found in good agreement with all of the experimental data. The cosmological variation of the fine-structure constant is also addressed.

scholarly journals Accelerating universe and the time-dependent fine-structure constant

2009 ◽  
Vol 5 (H15) ◽  
pp. 302-302
Author(s):  
Yasunori Fujii
Keyword(s):  
Fine Structure ◽  
Scalar Field ◽  
Structure Constant ◽  
Theoretical Background ◽  
Point Of View ◽  
Fine Structure Constant ◽  
Time Variability ◽  
Accelerating Universe ◽  
Tensor Theory ◽  
The Right

I start with assuming a gravitational scalar field as the dark-energy supposed to be responsible for the accelerating universe. Also from the point of view of unification, a scalar field implies a time-variability of certain “constants” in Nature. In this context I once derived a relation for the time-variability of the fine-structure constant α: Δα/α =ζ Ƶ(α/π) Δσ, where ζ and Ƶ are the constants of the order one, while σ on the right-hand side is the scalar field in action in the accelerating universe. I use the reduced Planckian units with c=ℏ =MP(=(8π G)−1/2)=1. I then compared the dynamics of the accelerating universe, on one hand, and Δα/α derived from the analyses of QSO absorption lines, Oklo phenomenon, also different atomic clocks in the laboratories, on the other hand. I am here going to discuss the theoretical background of the relation, based on the scalar-tensor theory invented first by Jordan in 1955.

scholarly journals Implications of gauge unification for time variation of the fine structure constant

2002 ◽  
Vol 528 (1-2) ◽  
pp. 121-128 ◽  
Author(s):  
Paul Langacker ◽  
Gino Segrè ◽  
Matthew J. Strassler
Keyword(s):  
Fine Structure ◽  
Time Variation ◽  
Structure Constant ◽  
Fine Structure Constant
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