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Klaus Behrndt

Publications and source records attributed to Klaus Behrndt.

57 records · Page 4Linked to original sources

F & H Monopoles

Supersymmetric monopoles of the heterotic string theory associated with arbitrary non-negative number of the left moving modes of the string states are presented. They include H monopoles and their T dual partners F monopoles (ALE instantons). Massive F = H monopoles are T self-dual. Solutions include also an infinite tower of generic T duality covariant non-singular in stringy frame F\&H monopoles with the bottomless throat geometry. The massless F = -H monopoles are invariant under combined T duality and charge conjugation converting a monopole into anti monopole. All F\&H monopoles can be promoted to the exact supersymmetric solutions of the heterotic string theory since the holonomy group is the compact $SO(9)$. The sigma models for ${\bf M}^8$ monopoles, which admit constant complex structures, have enhanced world-sheet supersymmetry: (4,1) in general and (4,4) for the left-right symmetric monopoles. The space-time supersymmetric GS light-cone action in monopole background is directly convertible into the world-sheet supersymmetric NSR action.

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O(6,22) BPS Configurations of the Heterotic String

We present a static multi-center magnetic solution of toroidally compactified heterotic string theory, which is T-duality covariant. The space-time geometry depends on the mass M and on the O(6,22)-norm N of the magnetic charges. For different range of parameters (M,N)-solution includes 1) two independent positive parameters extremal magnetic black holes with non-singular geometry in stringy frame ($a=1$ black holes included), 2) $a=\sqrt 3$ extremal black holes, 3) singular massive and massless magnetic white holes (repulsons). The electric multi-center solution is also given in an O(6,22)-symmetric form.

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The 10-D chiral null model and the relation to 4-D string solutions

The chiral null model is a generalization of the fundamental string and gravitational wave background. It is an example of a conformally invariant model in all orders in $α'$ and has unbroken supersymmetries. In a Kaluza--Klein approach we start in 10 dimensions and reduce the model down to 4 dimensions without making any restrictions. The 4-D field content is given by the metric, torsion, dilaton, a moduli field and 6 gauge fields. This model is self-dual and near the singularities asymptotically free. The relation to known IWP, Taub-NUT and rotating black hole solutions is discussed.

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