Penrose limits and maximal supersymmetry

TL;DR

The authors show that maximally supersymmetric Hpp-waves in M-theory and type IIB supergravity arise as Penrose limits of AdS×S backgrounds, and they classify the resulting geometries and fluxes, including the associated symmetry contractions. They further connect these limits to a large tension regime for brane probes in AdS×S, revealing that the probe dynamics reduces to either Minkowski space or an Hpp-wave background with a tractable, exactly quantizable string theory in the Hpp-wave case. The work provides explicit metric and flux mappings (including Rosen to Brinkman form) and demonstrates how the AdS×S isometry algebras contract to Heisenberg-type algebras, offering a unifying picture of AdS×S and pp-wave backgrounds. These results explain the origin and structure of the Hpp-waves and establish a framework for exact analyses of strings and branes in their plane-wave limits.

Abstract

We show that the maximally supersymmetric pp-waves of IIB superstring and M-theories can be obtained as a Penrose limit of the supersymmetric AdS x S solutions. In addition we find that in a certain large tension limit, the geometry seen by a brane probe in an AdS x S background is either Minkowski space or a maximally supersymmetric pp-wave.