  Four lectures on holography and the AdS/CFT correspondence applied to
condensed matter systems. The first lecture introduces the concept of a quantum
phase transition. The second lecture discusses linear response theory and Ward
identities. The third lecture presents transport coefficients derived from
AdS/CFT that should be applicable in the quantum critical region associated to
a quantum phase transition. The fourth lecture builds in the physics of a
superconducting or superfluid phase transition to the simple holographic model
of the third lecture.

High Energy Physics - Theory;Strongly Correlated Electrons