Varying G and Other Constants
نویسنده
چکیده
We review recent progress in the study of varying constants and attempts to explain the observed values of the fundamental physical constants. We describe the variation of G in Newtonian and relativistic scalar-tensor gravity theories. We highlight the behaviour of the isotropic Friedmann solutions and consider some striking features of primordial black hole formation and evaporation if G varies. We discuss attempts to explain the values of the constants and show how we can incorporate the simultaneous variations of several ’constants’ exactly by using higher-dimensional unified theories. Finally, we describe some new observational limits on possible space or time variations of the fine structure constant.
منابع مشابه
Density functional explorations of quadrupole coupling constants for BN, BP, AlN, and AlP graphene–like structures
Stabilizations and atomic level quadrupole coupling constant (CQ) properties have been investigated for graphene–like monolayers (G–monolayers) of boron nitride (BN), boron phosphide (BP), aluminum nitride (AlN), and aluminum phosphide (AlP) structures. To this aim, density functional theory (DFT) calculations have been performed to optimize the model structures and also to evaluate the CQ para...
متن کاملDensity functional explorations of quadrupole coupling constants for BN, BP, AlN, and AlP graphene–like structures
Stabilizations and atomic level quadrupole coupling constant (CQ) properties have been investigated for graphene–like monolayers (G–monolayers) of boron nitride (BN), boron phosphide (BP), aluminum nitride (AlN), and aluminum phosphide (AlP) structures. To this aim, density functional theory (DFT) calculations have been performed to optimize the model structures and also to evaluate the CQ para...
متن کاملQuantum Cosmology and Varying Physical Constants
The main task of this review is to discuss quantum cosmology minisuperspace models based on the Wheeler–DeWitt equation, which apart from the standard matter and 3-geometry configuration degrees of freedom, allow those related to the variability of physical constants—varying speed of light (VSL) c and varying gravitational constant G. The tunneling probability of the universe “from nothing” to ...
متن کاملCosmology with Varying Constants from a Thermodynamic Viewpoint
We study the variation of fundamental constants in cosmology while dealing with thermodynamic aspects of gravity. We focus on the variation of the speed of light, c, and Newton’s gravitational constant, G, with respect to cosmic time. We find the constraints on the possible variation of these constants by comparing varying constants of cosmological models with the latest observational data.
متن کاملFull Causal Bulk Viscous Lrs Bianchi I with Time Varying Constants
In this paper we study the evolution of a LRS Bianchi I Universe, filled with a bulk viscous cosmological fluid in the presence of time varying constants " but " taking into account the effects of a c-variable into the curvature tensor. We find that the only physical models are those which " constants " G and c are growing functions on time t, while the cosmological constant Λ is a negative dec...
متن کامل