On the consequences of a cosmological model with a time-dependent cosmological «constant» and the relationship between Einstein equivalence principle, Mach's principle and dirac's principle

1985 ◽  
Vol 87 (2) ◽  
pp. 148-156 ◽  
Author(s):  
Jung-Jeng Huang
Keyword(s):  
Cosmological Model ◽  
Cosmological Constant ◽  
Equivalence Principle ◽  
Time Dependent ◽  
Mach's Principle ◽  
Mach’S Principle ◽  
The Relationship

scholarly journals The Large Number Hypothesis and Einstein's Theory of Gravitation

1985 ◽  
Vol 38 (4) ◽  
pp. 547 ◽  
Author(s):  
Yun-Kau Lau
Keyword(s):  
Cosmological Model ◽  
Cosmological Constant ◽  
Matter Density ◽  
Time Dependent ◽  
Field Equations ◽  
Large Number Hypothesis ◽  
Theory Of Gravitation ◽  
The Mean ◽  
Limiting Case ◽  
The Universe

In an attempt to reconcile the large number hypothesis (LNH) with Einstein's theory of gravitation, a tentative generalization of Einstein's field equations with time-dependent cosmological and gravitational constants is proposed. A cosmological model consistent with the LNH is deduced. The coupling formula of the cosmological constant with matter is found, and as a consequence, the time-dependent formulae of the cosmological constant and the mean matter density of the Universe at the present epoch are then found. Einstein's theory of gravitation, whether with a zero or nonzero cosmological constant, becomes a limiting case of the new generalized field equations after the early epoch.

scholarly journals Gravitational Lagrangians, Mach’s Principle, and the Equivalence Principle in an Expanding Universe

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Hanno Essén
Keyword(s):  
Long Range ◽  
Equivalence Principle ◽  
Critical Density ◽  
Tensor Interaction ◽  
Expansion Velocity ◽  
Expanding Universe ◽  
Mach's Principle ◽  
Mach’S Principle ◽  
Long Range Interactions ◽  
Hubble Radius

Gravitational Lagrangians as derived by Fock for the Einstein-Infeld-Hoffmann approach, and by Kennedy assuming only a fourth rank tensor interaction, contain long range interactions. Here we investigate how these affect the local dynamics when integrated over an expanding universe out to the Hubble radius. Taking the cosmic expansion velocity into account in a heuristic manner it is found that these long range interactions imply Mach’s principle, provided the universe has the critical density, and that mass is renormalized. Suitable higher order additions to the Lagrangians make the formalism consistent with the equivalence principle.

scholarly journals A NEW COSMOLOGICAL CONSTANT MODEL

1996 ◽  
Vol 11 (01) ◽  
pp. 1-7 ◽  
Author(s):  
JORGE L. LOPEZ ◽  
D.V. NANOPOULOS
Keyword(s):  
Cosmological Model ◽  
Cosmological Constant ◽  
Hubble Parameter ◽  
Particle Physics ◽  
Time Dependent ◽  
Low Density ◽  
Universe Model ◽  
Planck Time ◽  
Age Of The Universe ◽  
The Universe

We propose a new cosmological model with a time-dependent cosmological constant (Λ∝1/t2), which starting at the Planck time as [Formula: see text], evolves to the present-day allowed value of [Formula: see text]. This scenario is supported by noncritical string theory considerations. We compute the age of the Universe and the time dependence of the scale factor in this model, and find general agreement with recent determinations of the Hubble parameter for substantial values of ΩΛ. This effectively low-density open Universe model differs from the traditional cosmological constant model, and has observable implications for particle physics and cosmology.

scholarly journals Deformation of the quintom cosmological model and its consequences

2018 ◽  
Vol 27 (03) ◽  
pp. 1850025 ◽  
Author(s):  
J. Sadeghi ◽  
B. Pourhassan ◽  
Z. Nekouee ◽  
M. Shokri
Keyword(s):  
Dark Energy ◽  
Phase Space ◽  
Cosmological Model ◽  
Cosmological Constant ◽  
Cosmological Parameters ◽  
Time Dependent ◽  
Noether Symmetry ◽  
Noncommutative Phase Space ◽  
Deformation Parameters ◽  
Noncommutative Parameter

In this paper, we investigate the effects of noncommutative phase-space on the quintom cosmological model. In that case, we discuss about some cosmological parameters and show that they depend on the deformation parameters. We find that the noncommutative parameter plays important role which helps to re-arrange the divergency of cosmological constant. We draw time-dependent scale factor and investigate the effect of noncommutative parameters. Finally, we take advantage from noncommutative phase-space and obtain the deformed Lagrangian for the quintom model. In order to discuss some cosmological phenomena as dark energy and inflation, we employ Noether symmetry.

scholarly journals Global versus local — Mach’s principle versus the equivalence principle

2016 ◽  
Vol 25 (12) ◽  
pp. 1644009 ◽  
Author(s):  
Douglas Singleton ◽  
Steve Wilburn
Keyword(s):  
General Relativity ◽  
Thermodynamic Properties ◽  
Equivalence Principle ◽  
Quantum Effects ◽  
Conceptual Basis ◽  
Quantum Fields ◽  
Mach's Principle ◽  
Mach’S Principle ◽  
Nonlocal Structure

The equivalence principle is the conceptual basis for general relativity. In contrast, Mach’s principle, although said to have been influential on Einstein in his formulation of general relativity, has not been shown to be central to the structure of general relativity. In this paper, we suggest that the quantum effects of Hawking and Unruh radiation are a manifestation of a thermal Mach’s principle, where the local thermodynamic properties of the system are determined by the nonlocal structure of the quantum fields which determine the vacuum of a given spacetime. By comparing Hawking and Unruh temperatures for the same local acceleration we find a violation of the Einstein elevator version of the equivalence principle, which vanishes in the limit that the horizon is approached.

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