A Penrose limit for type IIB $AdS_6$ solutions

TL;DR

This paper constructs a Penrose limit for type IIB $AdS_6$ solutions, revealing a universal pp-wave spacetime and enabling the calculation of string excitation spectra in a novel supergravity context.

Contribution

It introduces a new Penrose limit for $AdS_6$ solutions, providing explicit string spectra and a universal pp-wave background in this setting.

Findings

Derived a universal pp-wave spacetime from $AdS_6$ solutions.

Obtained the string excitation spectrum in the light cone gauge.

Identified the extremal point on the Riemann surface for the limit.

Abstract

In this paper a Penrose limit is constructed for type IIB $AdS_6\times S^2\times \Sigma$ supergravity solutions. These solutions are dual to five dimensional SCFTs related to (p,q) five brane webs, which can often be described in terms of long quiver gauge theories. The null geodesic from which the Penrose limit is constructed is localized at a unique point on the two dimensional Riemann surface $\Sigma$, where the $AdS_6$ and $S^2$ metric factors are extremal. The resulting pp-wave spacetime takes a universal form. The world sheet action of the Green-Schwarz string is quadratic in the light cone gauge and the spectrum of string excitations is obtained.