  We consider branes in refined topological strings. We argue that their
wave-functions satisfy a Schr\"odinger equation depending on multiple times and
prove this in the case where the topological string has a dual matrix model
description. Furthermore, in the limit where one of the equivariant rotations
approaches zero, the brane partition function satisfies a time-independent
Schroedinger equation. We use this observation, as well as the back reaction of
the brane on the closed string geometry, to offer an explanation of the
connection between integrable systems and N=2 gauge systems in four dimensions
observed by Nekrasov and Shatashvili.

High Energy Physics - Theory