The energy conservation method is based on knowledge of the state vector and measurements of nonconservative forces. This is or will be provided by CHAMP, GRACE and GOCE. Here the analysis of one month of CHAMP state vector and accelerometer data is described. The energy conservation method is used to estimate the gravity potential at satellite altitude. When doing so we consider the tidal pote...

The physics of quantum gravity is discussed within the framework of topological quantum field theory. Some of the principles are illustrated with examples taken from theories in which space-time is three dimensional.

A weak-field solution of Einstein’s equations is constructed. It is generated by a circular cosmic string externally supported against collapse. The solution exhibits a conical singularity, and the corresponding deficit angle is the same as for a straight string of the same linear energy density. This confirms the deficit-angle assumption made in the Frolov-Israel-Unruh derivation of the metric...

Abstract Scalar fields have had a long and controversial life in gravity theories, having progressed through many deaths and resurrections. The first scientific gravity theory, Newton’s, was that of a scalar potential field, so it was natural for Einstein and others to consider the possibility of incorporating gravity into special relativity as a scalar theory. This effort, though fruitless in ...

Logarithmic conformal field theories with vanishing central charge describe systems with quenched disorder, percolation or dilute self-avoiding polymers. In these theories the energy momentum tensor acquires a logarithmic partner. In this talk we address the construction of possible gravity duals for these logarithmic conformal field theories and present two viable candidates for such duals, na...

We present an alternative derivation of the gravitational field equations starting from the Newton’s law, which intrinsically brings in observer dependence in the theory. Projecting the Riemann curvature tensor appropriately as fit for an observer, taking a cue from Poisson’s equation, the Einstein’s equations immediately follow. Our derivation naturally adapts to Lovelock gravity theories wher...

We give all the exact solutions of the Einstein-Gauss-Bonnet Field Equations coupled with a scalar field in four dimensions under certain assumptions.

The vector potential is A=(μo/4π)qv/r, from which B=∇×A. Upon any acceleration of the charge, one finds a long range electric field, E=− ∂A/∂t. The range of this 1/r field far exceeds that from a charge, which goes as 1/r2 or a dipole which goes as 1/r3. This E field differs from Hertz’ solution for an oscillating charge. Hertz’ finding of TEM waves from an oscillating charge is flawed by the i...

We demonstrate that the emergence of a curved spacetime ‘effective Lorentzian geometry’ is a common and generic result of linearizing a classical scalar field theory around some non-trivial background configuration. This investigation is motivated by considering the large number of ‘analogue models’ of general relativity that have recently been developed based on condensedmatter physics, and as...

We discuss the two-dimensional dilaton gravity with a scalar field as the source matter. The coupling between the gravity and the scalar, massless, field is presented in an unusual form. We work out two examples of these couplings, and solutions with black-hole behaviour are discussed and compared with those found in the literature.