Related papers: Instantons For Black Hole Pair Production
In this work two new families of non-singular or regular black hole solutions are displayed. These black holes behave as de Sitter space near its center and have a well defined AdS asymptotic region for negative cosmological constant. These…
The effective action for string theory which takes into account non-minimal coupling of moduli admits multi-black hole solutions. The euclidean continuation of these solutions can be interpreted as an instanton mediating the splitting and…
By reduction along the time direction, black holes in 4 dimensions yield instantons in 3 dimensions. Each of these instantons contributes individually at order $\exp(-|Q|/g_s)$ to certain protected couplings in the three-dimensional…
Using a generalized Weyl formalism, we show how stationary, axisymmetric solutions of the four-dimensional vacuum Einstein equation can be turned into static, axisymmetric solutions of five-dimensional dilaton gravity coupled to a two-form…
We study regular Schwarzschild black holes in General Relativity as an alternative to the singular counterpart. We analyze two types of solutions which are completely parameterised by the ADM mass alone. We find that both families of…
We study Einstein gravity minimally coupled to a scalar field in a static, spherically symmetric space-time in four dimensions. Black hole solutions are shown to exist for a phantom scalar field whose kinetic energy is negative. These…
The dimensional reduction of black hole solutions in four-dimensional (4D) general relativity is performed and new 3D black hole solutions are obtained. Considering a 4D spacetime with one spacelike Killing vector, it is possible to split…
In the inflationary era, black holes came into existence together with the universe through the quantum process of pair creation. We calculate the pair creation rate from the no boundary proposal for the wave function of the universe. Our…
We present exact solutions in Einstein-aether theory in a static spherically symmetric background space with a spacelike aether field, as a difference with the usual selection of timelike aether field. We assume a coupling between the…
We analyze the quantum process in which a cosmic string breaks in an anti-de Sitter (AdS) background, and a pair of charged or neutral black holes is produced at the ends of the strings. The energy to materialize and accelerate the pair…
The imaginary part of the one loop effective action in external backgrounds can be efficiently computed using worldline instantons which are closed periodic paths in spacetime. Exact solutions for nonstatic backgrounds are only known in…
Exact solutions of Einstein's equations in 2+1-dimensional anti-de Sitter space containing any number of black holes are described. In addition to the black holes these spacetimes can possess ``internal'' structure. Accordingly the generic…
We consider a generalized three-dimensional theory of gravity which is specified by two fields, the graviton and the dilaton, and one parameter. This theory contains, as particular cases, three-dimensional General Relativity and…
Previous works on black hole shadows have been primarily focused on studying shadows in asymptotically flat and anti-de Sitter space times. In the present work, we find general expressions for asymptotically de Sitter black hole shadow as…
For self-gravitating, static, spherically symmetric, minimally coupled scalar fields with arbitrary potentials and negative kinetic energy (favored by the cosmological observations), we give a classification of possible regular solutions to…
In this review I discuss various aspects of some of the recently constructed black hole and soliton solutions in string theory. I begin with the axionic instanton and related solutions of bosonic and heterotic string theory. The latter…
We propose a method of determining solutions to the constraint equations of General Relativity approximately describing binary black holes in quasi-stationary circular orbits. Black holes with arbitrary linear momenta are constructed in the…
The spontaneous creation of primordial black holes in a violently expanding Universe is a well studied phenomenon. Based on quantum gravity arguments, it has been conjectured that the early Universe might have undergone a lower dimensional…
Through two exact solution families to the Einstein equation and the one-to-one correspondence between their free parameters, we show that the ensemble of collapsars with only close-to-implementing horizon in the Schwarzschild time…
Primordial black holes are considered to be pair created quantum-mechanically during inflation. In the context of General Relativity (GR), it has been shown that the pair creation rate is exponentially decreasing during inflation.…