We consider dilaton gravity theories in four spacetime dimensions parametrised by a constant a, which controls the dilaton coupling, and construct new exact solutions. We first generalise theâ€¦ (More)

We present simple, analytic solutions to the Einstein-Maxwell equation, which describe an arbitrary number of charged black holes in a spacetime with positive cosmological constant Î›. In the limit Î›â€¦ (More)

We study the problem of scalar particle production after inflation by an in-flaton field which is oscillating rapidly relative to the expansion of the universe. We use the framework of the chaoticâ€¦ (More)

There exists an upper limit on the mass of black holes when the cosmological constant Î› is positive. We study the collision of two black holes whose total mass exceeds this limit. Our investigationâ€¦ (More)

The issues of scaling symmetry and critical point behavior are studied for fluctuations about extremal charged black holes. We consider the scattering and capture of the spherically symmetric mode ofâ€¦ (More)