The exact description of NS5-branes in the Penrose limit

TL;DR

This paper constructs and analyzes exact plane wave backgrounds derived from NS5-branes with broken symmetry, connecting them to a five-dimensional Logarithmic CFT and solving string spectra explicitly.

Contribution

It provides a detailed construction of time-dependent plane wave backgrounds from NS5-branes and identifies their exact CFT description as a Logarithmic Conformal Field Theory.

Findings

Exact plane wave backgrounds with broken symmetry are constructed.

The corresponding Logarithmic CFT is identified and analyzed.

String spectra are explicitly solved in the light-cone gauge.

Abstract

We construct plane wave backgrounds with time-dependent profiles corresponding to Penrose limits of NS5-branes with transverse space symmetry group broken from SO(4) to SO(2)\times Z_N. We identify the corresponding exact theory as the five-dimensional Logarithmic Conformal Field Theory (CFT) arising from the contraction of the SU(2)_{N'}/U(1)\times SL(2,R)_{-N} exact CFT, times R^5. We study several general aspects and construct the free field representation in this theory. String propagation and spectra are also considered and explicitly solved in the light-cone gauge.