On Penrose Limits and Gauge Theories

TL;DR

This paper explores Penrose limits of various AdS backgrounds, revealing how nonconformal deformations affect string solvability and establishing connections between string modes and field theory operators.

Contribution

It analyzes Penrose limits of conformal and nonconformal backgrounds, showing the universality of nonconformal deformations and their impact on string solvability.

Findings

Penrose limit of AdS_5 x T^{1,1} matches that of AdS_5 x S^5 for a specific angular coordinate.

Nonconformal backgrounds lead to non-solvable worldsheet theories with x-dependent mass terms.

Universal deformation form in nonconformal cases affects string theory solvability.

Abstract

We discuss various Penrose limits of conformal and nonconformal backgrounds. In AdS_5 x T^{1,1}, for a particular choice of the angular coordinate in T^{1,1} the resulting Penrose limit coincides with the similar limit for AdS_5 x S^5. In this case an identification of a subset of field theory operators with the string zero modes creation operators is possible. For another limit we obtain a light-cone string action that resembles a particle in a magnetic field. We also consider three different types of backgrounds that are dual to nonconformal field theories: The Schwarzschild black hole in AdS_5, D3-branes on the small resolution of the conifold and the Klebanov-Tseytlin background. We find that in all three cases the introduction of nonconformality renders a theory that is no longer exactly solvable and that the form of the deformation is universal. The corresponding world sheet theory in the light-cone gauge has a \tau=x^+ dependent mass term.