Higher–dimensional theories imply that some constants, such as the gravitational constant and the strength of the gauge–couplings, are not fundamental constants. Instead they are related to the sizes of the extra–dimensional space, which are moduli fields in the four– dimensional effective theory. We study the cosmological evolution of the moduli fields appearing in brane world scenarios and di...

According to the Brans–Dicke theory, the value of the gravitational constant G which we measure at present is determined by the value of the Brans–Dicke scalar field φ at the end of inflation. However, due to quantum fluctuations of the scalar fields produced during inflation, the gravitational constant G(φ) may take different values in different exponentially large parts of the Universe. We in...

The basic motivation of this work is to attempt to explain the rapid primordial inflation and the observed slow late-time inflation by using the BransDicke theory of gravity. We show that the ratio of these two inflation parameters is proportional to the square root of the Brans-Dicke parameter ω (ω ≫ 1). We also calculate the Hubble parameter H and the time variation of the time dependent Newt...

We study theoretically the quantum motion of a neutron in a horizontal wave-guide in the gravitational field of the Earth. The wave-guide in question is equipped with a mirror below and a rough surface absorber above. We show that such a system acts as a quantum filter, i.e. it effectively absorbs quantum states with sufficiently high transversal energy but transmits low-energy states. The stat...

Participants judged the perceived center of three-dot displays at different orientations. In Experiment 1, the dots formed an equilateral triangle. The direction of the response distribution aligned with the largest dot, along axes of reflectional symmetry and with the gravitational down. In Experiment 2, we created isosceles triangles where the distance between one of the dot pairs was varied....

Equations of light, propagating from quasar to observer on earth, are integrated in the time-dependent gravitational field of the solar system by making use of either retarded or advanced solutions of the Einstein field equations. This technique allows to separate explicitly the effects associated with the propagation of gravity from those associated with light in the integral expression for th...

The quantum state of a wormhole can be represented by a path integral over all asymptotically Euclidean four-geometries and all matter fields which have prescribed values, the arguments of the wave function, on a three-surface S which divides the spacetime manifold into two disconnected parts. The ground-state wave function is picked out by requiring that there be no matter excitations in the a...

Introduction and main result Laboratory experiments on gravitation are usually performed with objects of constant density, so that the analysis of the forces concerns only the geometry of their shape. In an ideal experiment, the shapes of the constituent parts will be optimised to meet certain mathematical criteria, which ensure that the experiment has maximal sensitivity. Using this idea, the ...

Spontaneous emission of graviton rates for the quantum bouncer states are evaluated. The quantum problem of a ball bouncing above a ideal mirror was considered a long time ago, however just as a mere exercise of elementary quantum mechanics. Things did change since the quantization of energy of Ultra Cold Neutrons (UCN) bouncing above a mirror in the Earth’s gravitational field had been demonst...