Research Papers (JVN)

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Conformal quantization and space-time singularity
(World Scientiﬁc Publishing group, 1986-06-06) Joshi, P. S.; Narlikar, J. V.
This work generalizes earlier results of conformal quantization that within the full range of space-times conformal to any singular space-time satisfying Einstein's field equations for minimally coupled matter, the singular solutions form a set of zero-probability measure. A wider definition of space-time singularity that includes the curvature singularity assumed in the earlier work (op. cit.) is adapted and it is shown that the previous conclusion stands even when the present state of the universe is defined by wave functionals that are not necessarily wave packets. Within the present framework of quantum gravity therefore it seems extremely unlikely that the universe had a singular origin.
Black hole physics in globally hyperbolic space-times
(Indian Academy of Sciences, 1982-02-16) Joshi, P. S.; Narlikar, J. V.
The usual definition of a black hole is modified to make it applicable in a globally hyperbolic space-time. It is shown that in a closed globally hyperbolic universe the surface area of a black hole must eventually decrease. The implications of this breakdown of the black hole area theorem are discussed in the context of thermodynamics and cosmology. A modified definition of surface gravity is also given for non-stationary universes. The limitations of these concepts are illustrated by the explicit example of the Kerr-Vaidya metric.