scholarly journals SOLUTIONS TO COSMOLOGICAL PROBLEMS WITH ENERGY CONSERVATION AND VARYING c, G AND Λ

2001 ◽  
Vol 16 (15) ◽  
pp. 957-961 ◽  
Author(s):  
P. GOPAKUMAR ◽  
G. V. VIJAYAGOVINDAN
Keyword(s):  
Energy Conservation ◽  
Cosmological Constant ◽  
Coupling Strength ◽  
Cosmological Parameter ◽  
Gravitational Coupling ◽  
Speed Of Light ◽  
Present Solution ◽  
Previous Solution ◽  
Flatness Problem

The flatness and cosmological constant problems are solved with varying speed of light c, gravitational coupling strength G and cosmological parameter Λ, by explicitly assuming energy conservation of observed matter. The present solution to the flatness problem is the same as a previous solution in which energy conservation was absent.

scholarly journals A VARYING-e BRANE WORLD COSMOLOGY

2002 ◽  
Vol 17 (03) ◽  
pp. 175-184 ◽  
Author(s):  
DONAM YOUM
Keyword(s):  
Cosmological Model ◽  
Cosmological Constant ◽  
Electric Charge ◽  
Brane World ◽  
Speed Of Light ◽  
Cosmological Constant Problem ◽  
System Of Units ◽  
Flatness Problem

We study a varying electric charge brane world cosmology in the RS2 model obtained from a varying-speed-of-light brane world cosmology by redefining the system of units. We elaborate conditions under which the flatness problem and the cosmological constant problem can be resolved by such cosmological model.

INFLATION, QUINTESSENCE PROBLEM AND VARYING SPEED OF LIGHT

2002 ◽  
Vol 17 (05) ◽  
pp. 295-302
Author(s):  
SUBENOY CHAKRABORTY
Keyword(s):  
Cosmological Constant ◽  
Accelerated Expansion ◽  
Speed Of Light ◽  
Expansion Of The Universe ◽  
The Universe

In this paper it is shown that the present accelerated expansion of the Universe can be explained only by considering variation of the speed of light, without taking into account the cosmological constant or quintessence matter.

scholarly journals COSMOLOGICAL CONSTANT AND THE SPEED OF LIGHT

2001 ◽  
Vol 10 (01) ◽  
pp. 41-48 ◽  
Author(s):  
W. R. ESPÓSITO MIGUEL ◽  
J. G. PEREIRA
Keyword(s):  
Gravitational Field ◽  
Cosmological Constant ◽  
Electromagnetic Waves ◽  
Light Propagation ◽  
Wave Optics ◽  
Speed Of Light ◽  
Positive Cosmological Constant ◽  
Velocity Of Light ◽  
Refractive Medium ◽  
The Relationship

By exploring the relationship between the propagation of electromagnetic waves in a gravitational field and the light propagation in a refractive medium, it is shown that, in the presence of a positive cosmological constant, the velocity of light will be smaller than its special relativity value. Then, restricting again to the domain of validity of geometrical optics, the same result is obtained in the context of wave optics. It is argued that this phenomenon and the anisotropy in the velocity of light in a gravitational field are produced by the same mechanism.

scholarly journals Newton's Third Law in the Framework of Special Relativity for Charged Bodies

2021 ◽  
Author(s):  
Asher Yahalom ◽  
Shailendra Rajput
Keyword(s):  
Energy Conservation ◽  
Signal Propagation ◽  
Total Force ◽  
Speed Of Light ◽  
Electrons And Ions ◽  
Finite Period ◽  
Finite Distance ◽  
The Subject ◽  
Third Law ◽  
External Forces

Abstract Newton's third law states that any action is countered by a reaction of equal magnitude but opposite direction. The total force in a system not affected by external forces is thus zero. However, according to the principles of relativity, a signal cannot propagate at speeds exceeding the speed of light. Hence the action and reaction cannot be generated at the same time due to the relativity of simultaneity. Thus, the total force cannot be null at a given time. In a previous paper \cite{MTAY1}, we have shown that Newt\-on'n third law cannot strictly hold in a distributed system, where the different parts are at a finite distance from each other. This is due to the finite speed of signal propagation, which cannot exceed the speed of light in the vacuum. A specific example of two current loops with time dependent currents demonstrated that the summing of the total force in the system does not add up to zero. This analysis led to the suggestion of a relativistic engine \cite{MTAY3,AY1}. As the system is affected by a total force for a finite period, the system acquires mechanical momentum and energy. Now the question then arises how can we accommodate the law of momentum and energy conservation. The subject of momentum conversation was discussed in \cite{MTAY4}, while preliminary results regarding energy conservation were discussed in \cite{AY2,RY,RY2}. Previous analysis relied on the fact that the bodies were macroscopically natural, which means that the number of electrons and ions is equal in every volume element. Here we relax this assumption and study charged bodies, thus analyzing the consequences on a possible electric relativistic engine.

scholarly journals Newton's Third Law in the Framework of Special Relativity for Charged Bodies

2021 ◽  
Author(s):  
Asher Yahalom ◽  
Shailendra Rajput
Keyword(s):  
Energy Conservation ◽  
Signal Propagation ◽  
Total Force ◽  
Speed Of Light ◽  
Electrons And Ions ◽  
Finite Period ◽  
Finite Distance ◽  
The Subject ◽  
Third Law ◽  
External Forces

Newton's third law states that any action is countered by a reaction of equal magnitude but opposite direction. The total force in a system not affected by external forces is thus zero. However, according to the principles of relativity, a signal cannot propagate at speeds exceeding the speed of light. Hence the action and reaction cannot be generated at the same time due to the relativity of simultaneity. Thus, the total force cannot be null at a given time. In a previous paper \cite{MTAY1}, we have shown that Newt\-on'n third law cannot strictly hold in a distributed system, where the different parts are at a finite distance from each other. This is due to the finite speed of signal propagation, which cannot exceed the speed of light in the vacuum. A specific example of two current loops with time dependent currents demonstrated that the summing of the total force in the system does not add up to zero. This analysis led to the suggestion of a relativistic engine \cite{MTAY3,AY1}. As the system is affected by a total force for a finite period, the system acquires mechanical momentum and energy. Now the question then arises how can we accommodate the law of momentum and energy conservation. The subject of momentum conversation was discussed in \cite{MTAY4}, while preliminary results regarding energy conservation were discussed in \cite{AY2,RY,RY2}. Previous analysis relied on the fact that the bodies were macroscopically natural, which means that the number of electrons and ions is equal in every volume element. Here we relax this assumption and study charged bodies, thus analyzing the consequences on a possible electric relativistic engine.

scholarly journals THE NON-RELATIVISTIC LIMIT OF THE EULER–NORDSTRÖM SYSTEM WITH COSMOLOGICAL CONSTANT

2009 ◽  
Vol 21 (07) ◽  
pp. 821-876 ◽  
Author(s):  
JARED SPECK
Keyword(s):  
Sobolev Space ◽  
Cosmological Constant ◽  
Singular Limit ◽  
Poisson System ◽  
Speed Of Light ◽  
Relativistic Limit ◽  
Sobolev Estimates ◽  
Space Launch ◽  
The Family ◽  
Energy Currents

In this paper, we study the singular limit c → ∞ of the family of Euler–Nordström systems indexed by the parameters κ2 and c[Formula: see text], where κ2 > 0 is the cosmological constant and c is the speed of light. Using Christodoulou's techniques to generate energy currents, we develop Sobolev estimates that show initial data belonging to an appropriate Sobolev space launch unique solutions to the [Formula: see text] system that converge to corresponding unique solutions of the Euler–Poisson system with the cosmological constant κ2 as c tends to infinity.

scholarly journals Gravitational coupling and the cosmological constant

2018 ◽  
Vol 27 (08) ◽  
pp. 1850086
Author(s):  
Yousef Bisabr
Keyword(s):  
Cosmological Constant ◽  
Equivalence Principle ◽  
Weak Equivalence ◽  
Gravitational Coupling ◽  
Dynamical Mechanism ◽  
Metric Tensor ◽  
Weak Equivalence Principle ◽  
Gravitational Model ◽  
Expansion Of The Universe ◽  
The Universe

We deal with a dynamical mechanism in which a large cosmological constant, as suggested by inflationary scenarios, decays due to expansion of the universe. This mechanism has its origin in the gravitational coupling of the vacuum density. We assume that the vacuum couples anomalously to gravity that is the metric tensor that appears the gravitational part is not the same as that appears the matter part as suggested by weak equivalence principle. Instead, the two metric tensors are taken to be conformally related. We show that this provides a dynamical mechanism which works during expansion of the universe. We also consider some observational consequences of such a gravitational model.

GRAVITATIONAL COUPLING FUNCTION IN SCALAR–TENSOR THEORIES

1998 ◽  
Vol 13 (22) ◽  
pp. 3915-3927 ◽  
Author(s):  
B. MODAK ◽  
S. KAMILYA
Keyword(s):  
Cosmological Constant ◽  
Coupling Function ◽  
Asymptotic Region ◽  
Gravitational Coupling ◽  
Exit Problem ◽  
Cosmological Solutions ◽  
Gravity Theories

We present the gravitational coupling function ω(φ) in scalar tensor gravity theories as allowed by the Nöther symmetry. Some exact cosmological solutions have been presented in the scalar tensor gravity theories including cosmological constant using the above coupling function ω(φ) in the spatially flat homogeneous and isotropic background. The solutions are exponentially expanding in the asymptotic region and these inflationary solutions has the so-called graceful exit problem.

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