Related papers: String Theory in a Pinch: Resolving the Gregory-La…
We present a number of qualitative arguments which strongly suggest that extremal dyonic black holes in the 4--dimensional low energy, classical field theory limit of toroidally compactified heterotic string theory represent largely…
We investigate the conformal string $\sigma $-model corresponding to a general five-dimensional non-extremal black hole solution. In the horizon region the theory reduces to an exactly solvable conformal field theory. We determine the…
We briefly review the present status of string theory from the viewpoint of its implications on the short-distance space-time structure and black hole physics. Special emphases are given on two closely related issues in recent developments…
Plenty of efforts have been made to explore the black string and its instability, but the fate of the black strings with fewer extra dimensions is still inconclusive. Now starting from the 5D uniform black string, we show that the EHT…
We describe new numerical methods to solve the static axisymmetric vacuum Einstein equations in more than four dimensions. As an illustration, we study the compactified non-uniform black string phase connected to the uniform strings at the…
We consider black hole production at the LHC in a generic scenario with many extra dimensions where the Standard Model fields are confined to a brane. With $\sim 20$ dimensions the hierarchy problem is shown to be naturally solved without…
The holographic solution is a new exact solution to the Einstein field equations. It describes a compact self-gravitating object with properties similar to a black hole. Its entropy and temperature at infinity are proportional to the…
We construct numerically static non-uniform black string solutions in six dimensions by using pseudo-spectral methods. An appropriately designed adaptation of the methods in regard of the specific behaviour of the field quantities in the…
We investigate (2+1)-dimensional black strings in the Kaluza-Klein spacetime. The system is classically stable as long as the horizon size is much larger than the size of the compact space. Semiclassically, however, the horizon size shrinks…
This thesis investigates two main topics concerning black holes in extensions of general relativity inspired by string theory. First, the structure of the equations of motion underlying black hole solutions is considered, in theories of…
We present the static, spherically symmetric solutions of the low energy $d = 4$ string. They form a simple generalisation of the Schwarzschild solution and describe the gravitational field of a spherical star in perturbative string theory.…
We derive a class of solutions to the string sigma-model equations for the closed bosonic string. The tachyon field is taken to form a constant condensate and the beta-function equations at one-loop level are solved for the evolution of the…
Black branes and strings are generally unstable against a certain sector of gravitational perturbations. This is known as the Gregory-Laflamme instability. It has been recently argued that there exists another general instability affecting…
We find all the classical solutions (minimal surfaces) of open or closed strings in {\it any} two dimensional curved spacetime. As examples we consider the SL(2,R)/R two dimensional black hole, and any 4D black hole in the Schwarzschild…
We study the time evolution of a $3+1$ dimensional spacetime, where space is a large three-sphere, due to small perturbations of the background fields. We focus on two classes of deformations. One corresponds on the worldsheet to…
We investigate the black hole - string transition in the two-dimensional Lorentzian black hole system from the exact boundary states that describe the rolling D-brane falling down into the two-dimensional black hole. The black hole - string…
Four-dimensional homogeneous static and rotating black strings in dynamical Chern-Simons modified gravity, with and without torsion, are presented. Each solution is supported by a scalar field that depends linearly on the coordinate that…
We analyze the origin of separability for rotating black holes in string theory, considering both massless and massive geodesic equations as well as the corresponding wave equations. We construct a conformal Killing-Stackel tensor for a…
We show that spacetime curvature alone can classically stabilize black strings. Working within a consistent five-dimensional dilaton-gravity system with a flat brane, we find that sufficiently large black strings are classically stable when…
Two dimensional classical string theory is solved in any curved spacetime. The complete spacetime required to describe the classical string motions turns out to be larger than the global space required by complete particle geodesics. The…