Counting string theory standard models

DEVELOPMENT IN STRING THEORY

The string theory is a fast moving subject, both physics wise and in the respect of mathematics. In order to keep up with the discipline it is important to move with new ideas which are being stressed. Here I wish to give extracts from new papers of ideas which I have recently found interesting. There are six papers which are involved: I ."Strings formulated directly in 4 dimensions " A. N...

Counting Dyons in N = 4 String Theory

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 en-tropy. We give a derivation of this result in terms of the type II ve-brane compactiied on K3, by assuming that its uctuations are described by...

Bulk viscous string cosmological models in Saez – Ballester theory of gravitation

Spatially homogeneous Bianchi type-II, VIII and IX anisotropic, as well as isotropic cosmological models can be obtained in a scalar tensor theory of gravitation proposed by Saez and Ballester (1986) when the source for energy momentum tensor is a bulk viscous fluid containing one-dimensional cosmic strings. All the models obtained and presented here are expanding, non-rotating and accelerating...

Counting String /

We report on some recent work with M. R. Douglas and B. Shiffman on vacuum statistics for flux compactifications in string/M theory.

Complex geometry and vacua: Counting universes in string theory