Any probe which crosses the horizon of a black hole should be absorbed. In M(atrix) theory, for 0-brane probes of Schwarzschild black holes, we argue that the relevant absorption mechanism is a tachyon instability which sets in at the horizon. We give qualitative arguments, and some quantitative large-N calculations, in support of this claim. The tachyon instability provides an attractive mecha...

A family of black-hole solutions in the model with 1-component perfect fluid is obtained. The metric of any solution contains (n − 1) Ricci-flat “internal space” metrics and for certain equations of state (pi = ±ρ) coincides with the metric of black brane (or black hole) solution in the model with antisymmetric form. Certain examples (e.g. imitating M2 and M5 black branes) are considered. The p...

We present spherically symmetric black hole solutions for Einstein gravity coupled to anisotropic matter. We show that these black holes have arbitrarily short hair, and argue for stability by showing that they can arise from dynamical collapse. We also show that a recent ‘no short hair’ theorem does not apply to these solutions. Pacs numbers: 04.20.Jb, 04.40.Nr, 04.70.Bw Typeset using REVTEX

We study correlation functions of coset constructions by utilizing the method of gauge dressing. As an example we apply this method to the minimal models and to the Witten 2D black hole. We exhibit a striking similarity between the latter and the gravitational dressing. In particular, we look for logarithmic operators in the 2D black hole. e-mail: [email protected] e-mail: a.lewis1@...

We examine the dynamics of extended branes, carrying lower dimensional brane charges, wrapping black holes and black hole microstates in M and Type II string theory. We show that they have a universal dispersion relation typical of threshold bound states with a total energy equal to the sum of the contributions from the charges. In near-horizon geometries of black holes, these are BPS states, a...

We present spherically symmetric black hole solutions for Einstein gravity coupled to anisotropic matter. We show that these black holes have arbitrarily short hair, and argue for stability by showing that they can arise from dynamical collapse. We also show that a recent ‘no short hair’ theorem does not apply to these solutions. Pacs numbers: 04.20.Jb, 04.40.Nr, 04.70.Bw Typeset using REVTEX

– We show, by studying in detail the market prices of options on liquid markets, that the market has empirically corrected the simple, but inadequate Black-Scholes formula to account for two important statistical features of asset fluctuations: “fat tails” and correlations in the scale of fluctuations. These aspects, although not included in the pricing models, are very precisely reflected in t...

This paper will derive the Black-Scholes pricing model of a European option by calculating the expected value of the option. We will assume that the stock price is log-normally distributed and that the universe is riskneutral. Then, using Ito’s Lemma, we will justify the use of the risk-neutral rate in these initial calculations. Finally, we will prove put-call parity in order to price European...

We start by pointing out that certain Riemann surfaces appear rather naturally in the context of wave equations in the black hole background. For a given black hole there are two closely related surfaces. One is the Riemann surface of complexified “tortoise” coordinate. The other Riemann surface appears when the radial wave equation is interpreted as the Fuchsian differential equation. We study...

In this paper we try to answer the main question: what is a quantum black hole?