Generating branes via sigma-models

الأصل · EN

Starting with the D-dimensional Einstein-dilaton-antisymmetric form equations and assuming a block-diagonal form of a metric we derive a (D-d)-dimensional σ-model with the target space SL(d,R)/SO(d) × SL(2,R)/SO(2) × R or its non-compact form. Various solution-generating techniques are developed and applied to construct some known and some new p-brane solutions. It is shown that the Harrison transformation belonging to the SL(2,R) subgroup generates black p-branes from the seed Schwarzschild solution. A fluxbrane generalizing the Bonnor-Melvin-Gibbons-Maeda solution is constructed as well as a non-linear superposition of the fluxbrane and a spherical black hole. A new simple way to endow branes with additional internal structure such as plane waves is suggested. Applying the harmonic maps technique we generate new solutions with a non-trivial shell structure in the transverse space (`matrioshka' p-branes). It is shown that the p-brane intersection rules have a simple geometric interpretation as conditions ensuring the symmetric space property of the target space. Finally, a Bonnor-type symmetry is used to construct a new magnetic 6-brane with a dipole moment in the ten-dimensional IIA theory.