We review properties of theories for the variation of gravitation and fine structure 'constants'. We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that are consistent with time variation in the fine structure constant since a redshift of 3.5. The behaviour of a simple class of varying-alpha cosmologies is outlined in...

A brief review is offered of the theoretical background concerning dark energy: what is required by observations, what sort of models are being considered, and how they fit into particle physics and gravitation. Contribution to the SNAP (SuperNova Acceleration Probe) Yellow Book.

We investigate the possibility of constructing a locally supersymmetric extension of NGT (Nonsymmetric Gravitation Theory), based on the graded extension of the Poincaré group. In the framework of the simple model that we propose, we end up with a no-go result, namely the impossibility of cancelling some linear contribution in the gravitino field. This drawback seems to seriously undermine the ...

In this study, in context of general relativity we consider Einstein, Bergmann-Thomson, Møller and Landau-Lifshitz energy momentum definitions and we compute the total energy distribution (due to matter and fields including gravitation) of the universe based on Szekeres class I and class II space-times. We show that Einstein and Bergmann-Thomson definitions of the energy-momentum complexes give...

We shortly review a series of novel ideas on the physics of hadrons and nuclear matter. Despite being vastly different in scope and content, these models share a common attribute, in that they offer unconventional viewpoints on infrared QCD and nuclear phenomena. In a sense, they are reminiscent of the plethora of formulations that have been developed over the years on classical gravitation: ma...

I have reviewed the historical and contemporary experiments that guide us in choosing a post-Newtonian, relativistic gravitational theory. The foundation experiments essentially constrain gravitation theory to be a metric theory in which matter couples solely to one gravitational field, the metric field, although other cosmological gravitational fields may exist. The metric field for any metric...

We apply the principle of energy conservation to the motion of the test particle in gravitational field by requiring that its energy, gained by gravitation, has to be balanced by decrease of its rest mass. Due to the change of mass in gravitational field Newton's force law between gravitating bodies is modified, too. With this modified force law we build up the the classical field theory of gra...