Related papers: Accelerating Branes and the String/Black Hole Tran…
An effective string theory in physically relevant cosmological and black hole space times is reviewed. Explicit computations of the quantum string entropy, partition function and quantum string emission by black holes (Schwarzschild,…
In some kinds of classical dilaton theory there exist black holes with (i) infinite horizon area $A$ or infinite $F$ (the coefficient at curvature in Lagrangian) and (ii) zero Hawking temperature $T_{H}$. For a generic static black hole,…
We study the geometry of the two dimensional string theoretic black hole under tachyonic perturbations. These perturbations are restricted to affect only the metric and the dilaton, while other string theoretic excitations (like the axion)…
We develop the effective worldvolume theory for the dynamics of black branes with charges of the kind that arise in many supergravities and low-energy limits of string theory. Using this theory, we construct numerous new rotating black…
We present a static solution for $d = 2$ critical string theory including the tachyon $T$ but not its potential $V(T)$. This solution thus incorporates tachyon back reaction and, when $T = 0$, reduces to the black hole solution. When $T…
We perform canonical quantization of the open string on a unstable D-brane in the background of the tachyon condensation. Evaluating the Polyakov path-integral on a stripe, we obtain the field theoretical propagator in the open string…
Branes are ubiquitous elements of any low-energy limit of string theory. We point out that negative tension branes violate all the standard energy conditions of the higher-dimensional spacetime they are embedded in; this opens the door to…
We further study the nonperturbative formulation of two-dimensional black holes. We find a nonlinear differential equation satisfied by the tachyon in the black hole background. We show that singularities in the tachyon field configurations…
It is well known that one-loop free energy of closed strings diverges above the Hagedorn temperature. One explanation for this divergence is that a `winding mode' in the Euclidean time direction becomes tachyonic above the Hagedorn…
We derive the wave equation for a minimally coupled scalar field in the background of a general rotating five-dimensional black hole. It is written in a form that involves two types of thermodynamic variables, defined at the inner and outer…
For most black holes in string theory, the Schwarzschild radius in string units decreases as the string coupling is reduced. We formulate a correspondence principle, which states that (i) when the size of the horizon drops below the size of…
We argue that classical $(\alpha')$ effects qualitatively modify the structure of Euclidean black hole horizons in string theory. While low energy modes experience the geometry familiar from general relativity, high energy ones see a rather…
We study physical properties and global structures of a time-dependent, spherically symmetric solution obtained via the dimensional reduction of intersecting M-branes. We find that the spacetime describes a maximally charged black hole…
We review the recent developments in superstrings. We start with a brief summary of various consistent superstring theories and discuss T-duality which necessarily leads to the presence of D-branes. The properties of D-branes are summarized…
The past year has seen enormous progress in string theory. It has become clear that all of the different string theories are different limits of a single theory. Moreover, in certain limits, one obtains a new, eleven-dimensional structure…
One interesting proposal to solve the black hole information loss paradox without modifying either general relativity or quantum field theory, is the soft hair, a diffeomorphism charge that records the anisotropic radiation in the…
The classical black hole background of two-dimensional string theory is examined after including the effect of the tachyon field. Keeping all terms upto $O(T^2)$, and making no other approximations, the only consistent classical solution to…
We discuss the semiclassical approximation to the level density of (super) strings propagating in non-compact coset manifolds $G/H$. We show that the WKB ansatz agrees with heuristic red-shift arguments with respect to the ``exact" sigma…
We revisit the physical effects of discrete $\mathbb{Z}_p$ gauge charge on black hole thermodynamics, building on the seminal work of Coleman, Preskill, and Wilczek. Realising the discrete theory from the spontaneous breaking of an Abelian…
In previous papers we have shown how strings in a two-dimensional target space reconcile quantum mechanics with general relativity, thanks to an infinite set of conserved quantum numbers, ``W-hair'', associated with topological soliton-like…