54629664
A unified quantum theory I: Gravity interacting with a Yang-Mills field
Using the results and techniques of a previous paper where we proved the quantization of gravity we extend the former result by adding a Yang-Mills functional and a Higgs term to the Einstein-Hilbert action.
14951562
The mass of a Lorentzian manifold
We define a physically reasonable mass for an asymptotically Robertson-Walker (ARW) manifold which is uniquely defined in the case of a normalized representation.
15442219
Quantum cosmological Friedman models with a massive Yang–Mills field
We prove the existence of a spectral resolution of the Wheeler–DeWitt equation when the matter field is provided by a massive Yang–Mills field. The resolution is achieved by first solving the free eigenvalue problem for the gravitational field and then the constrained eigenvalue problem for the Yang–Mills field. In the latter case, the mass of the Yang–Mills field assumes the role of the eigenvalue.
9548206
On the foliation of space-time by constant mean curvature hypersurfaces
We prove that the mean curvature $\tau$ of the slices given by a constant mean curvature foliation can be used as a time function, i.e. $\tau$ is smooth with non-vanishing gradient.
14259478
Transition from big crunch to big bang in brane cosmology
We consider branes N = I × S0, where S0 is an n–dimensional space form, not necessarily compact, in a Schwarzschild-AdS(n+2) bulk N . The branes have a big crunch singularity. If a brane is an ARW space, then, under certain conditions, there exists a smooth natural transition flow through the singularity to a reflected brane N , which has a big bang singularity and which can be viewed as a brane in a reflected Schwarzschild-AdS(n+2) bulk N . The joint branes N ∪ N can thus be naturally embedded in R × S0, hence there exists a second possibility of defining a smooth transition from big crunch to big bang by requiring that N ∪ N forms a C∞-hypersurface in R × S0. This last notion of a smooth transition also applies to branes that are not ARW spaces, allowing a wide range of possible equations of state.
14435367
The inverse mean curvature flow in cosmological spacetimes
We prove that the leaves of an inverse mean curvature flow provide a foliation of a future end of a cosmological spacetime $N$ under the necessary and sufficent assumptions that $N$ satisfies a future mean curvature barrier condition and a strong volume decay condition. Moreover, the flow parameter $t$ can be used to define a new physically important time function.
123586923
A resonance analysis of electroproduction data
We determinedN* electromagnetic transition form factors using π- and η-electroproduction data in the resonance region published till December, 1978. We discuss problems with the results obtained by various experimental groups. The method of analysis is a modification of the procedure used by Devenish and Lyth. Using the new photoproduction results of Barbour and Crawford and the δ- and η-data published till 1978, we are able to parametrise all multipoles in a unique way and to describe the background without further high energy input. Thus a better description of the data with less assumptions is achieved. However, it is still not possible to determine more multipoles than previously.