We present a microscopic index formula for the degeneracy of dyons in four-dimensional N = 4 string theory. This counting formula is manifestly symmetric under the duality group, and its asymptotic growth reproduces the macroscopic Bekenstein-Hawking entropy. We give a derivation of this result in terms of the type II five-brane compactified on K3, by assuming that its fluctuations are describe...

We have designed, prototyped, and evaluated the Legend file system, which exploits the ability to regenerate lost files to improve reliability. Unlike RAID-5 and RAID-6, Legend degrades gracefully as the number of failed storage devices increases. Legend also mitigates the high storage capacity overhead imposed by n-way replications. Combined with existing methods, Legend can form another line ...

Hisakazu Minakata, Hiroshi Nunokawa, Stephen Parke 1 Department of Physics, Tokyo Metropolitan University 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan [email protected] 2 Instituto de F́ısica Teórica, Universidade Estadual Paulista Rua Pamplona 145, 01405-900 São Paulo, SP Brazil [email protected] 3 Theoretical Physics Department, Fermi National Accelerator Laboratory P.O.Box ...

Symbolic perturbation by innnitely small values removes degeneracies in geometric algorithms and enables programmers to handle only generic cases: there are a few such cases, whereas there are an overwhelming number of degenerate cases. Current perturbation schemes have limitations, presented below. To overcome them, this paper proposes to use an-arithmetic, i.e. to represent in an explicit way...

Finding the exact, quantum corrected metric on the hypermultiplet moduli space in Type II string compactifications on Calabi-Yau threefolds is an outstanding open problem. We address this issue by relating the quaternionic-Kähler metric on the hypermultiplet moduli space to the complex contact geometry on its twistor space. In this framework, Euclidean D-brane instantons are captured by contact...

W e quantify the observation by Kender and Freudenstein [6] that degenerate views occupy a significant fraction of the viewing sphere surrounding an object. This demonstrates that systems for recognition must explicitly account f o r the possibility of view degeneracy. W e show that view degeneracy cannot be detected f rom a single camera viewpoint. As a result, systems designed to recognize ob...

Over the past few years the understanding of the microscopic theory of black hole entropy has made important conceptual progress by recognizing that the degeneracies are encoded in partition functions which are determined by higher rank automorphic representations, in particular in the context of Siegel modular forms of genus two. In this brief review some of the elements of this framework are ...