Conformal Transformations near Naked Singularities -i

بررسی شکافتگی کوچک و دیگر تکینگی‌های آینده عالم و برقراری قانون دوم ترمودینامیک در نظریه

The future singularities are possible in a universe that is described by F(R) theory. In previous studies the occurrence of the singularities in F(R) theory have been considered by using a special function for the Hubble parameter and calculating the F(R) function for each of the singularities. Using the specified Hubble parameter causes some difficulties in the study of the second law of therm...

On Infinitesimal Conformal Transformations of the Tangent Bundles with the Generalized Metric

Let  be an n-dimensional Riemannian manifold, and  be its tangent bundle with the lift metric. Then every infinitesimal fiber-preserving conformal transformation  induces an infinitesimal homothetic transformation on .  Furthermore,  the correspondence   gives a homomorphism of the Lie algebra of infinitesimal fiber-preserving conformal transformations on  onto the Lie algebra of infinitesimal ...

Black holes and singularities in string theory

This is a summary of a lecture I gave at the workshop on dynamics and thermodynamics of black holes and naked singularities at Politecnico Milano. It is directed to a non-expert audience and reviews several ways in which string theory accounts for black hole microstates. In particular, I give an elementary introduction to the correspondence principle by Horowitz/Polchinski, to the state countin...

A Characterization of the Infinitesimal Conformal Transformations on Tangent Bundles

Gravitational Collapse, Black Holes and Naked Singularities

This article gives an elementary review of gravitational collapse and the cosmic censorship hypothesis. Known models of collapse resulting in the formation of black holes and naked singularities are summarized. These models, when taken together, suggest that the censorship hypothesis may not hold in classical general relativity. The nature of the quantum processes that take place near a naked s...