Constraints on the geometry of a static spherically symmetric black hole are obtained by requiring the spacetime curvature to be analytic at the event horizon. For a zero temperature black hole further constraints are obtained by also requiring that the semiclassical trace equation be satisfied when conformally invariant fields are present. It is found that zero temperature black holes whose si...

The now-famous Majumdar-Papapetrou exact solution of the EinsteinMaxwell equations describes, in general, N static, maximally charged black holes balanced under mutual gravitational and electrostatic interaction. When N = 2, this solution defines the two-black-hole spacetime, and the relativistic two-center problem is the problem of geodesic motion on this static background. Contopoulos and a n...

We employ an effective gravitational stellar final collapse model which contains the relevant physics involved in this complex phenomena: spherical radical infall in the Schwarzschild metric of the homogeneous core of an advanced star, giant magnetic dipole moment, mag-netohydrodynamic material response and realistic equations of state (EOS). The electromagnetic pulse is computed both for mediu...

We present new static spherically-symmetric exact solutions of Einstein equations with the quintessential matter surrounding a black hole charged or not as well as for the case without the black hole. A condition of additivity and linearity in the energy-momentum tensor is introduced, which allows one to get correct limits to the known solutions for the electromagnetic static field implying the...

A unified first law of black-hole dynamics and relativistic thermodynamics is derived in spherically symmetric general relativity. This equation expresses the gradient of the active gravitational energy E according to the Einstein equation. Projecting the equation along the flow of thermodynamic matter and along the trapping horizon of a black hole yield, respectively, first laws of relativisti...

By analysing the infinite-dimensional midisuperspace of spherically symmetric dust matter universes, and applying it to collapsing dust stars, one finds that the general quantum state is a bound state. This leads to a discrete spectrum. To an outside observer, the geometry is static if the initial radius of the collapsing star is smaller then the Schwarzschild radius. In that case the discrete ...

In this paper, we consider the quantum area spectrum for a rotating and charged (Kerr-Newman) black hole. Generalizing a recent study on Kerr black holes (which was inspired by the static-black hole formalism of Barvinsky, Das and Kunstatter), we show that the quantized area operator can be expressed in terms of three quantum numbers (roughly related to the mass, charge and spin sectors). More ...

Security is an important need in wireless mesh networks to give safe and shared information between wireless non-static nodes. In wireless network nodes has ability to act correctly and route the packets. Wireless mesh networks unusual method of producing,keeping and sharing information ability of mobile objects to show spontaneous and cheap adjusting arrangement itself.There are different type...