Penrose limits, supergravity and brane dynamics

TL;DR

This paper studies the Penrose limits of supergravity and string/M-theory backgrounds, demonstrating symmetry preservation, classifying limits for key solutions, and exploring implications for brane dynamics and cosmological models.

Contribution

It provides a comprehensive classification of Penrose limits for various supergravity solutions and reveals their interpretation as large tension limits for branes.

Findings

Symmetries do not decrease in Penrose limits.

Complete classification of Penrose limits for AdS x S and brane solutions.

Penrose limit as a large tension limit for branes.

Abstract

We investigate the Penrose limits of classical string and M-theory backgrounds. We prove that the number of (super)symmetries of a supergravity background never decreases in the limit. We classify all the possible Penrose limits of AdS x S spacetimes and of supergravity brane solutions. We also present the Penrose limits of various other solutions: intersecting branes, supersymmetric black holes and strings in diverse dimensions, and cosmological models. We explore the Penrose limit of an isometrically embedded spacetime and find a generalisation to spaces with more than one time. Finally, we show that the Penrose limit is a large tension limit for all branes including those with fields of Born--Infeld type.