  In the last 25 years a new understanding has evolved of the role of
information in quantum mechanics. At the same time there has been tremendous
progress in atomic/optical physics and condensed matter physics, and
particularly at the interface between these two formerly distinct fields, in
developing experimental systems whose quantum states are long-lived and which
can be engineered to perform quantum information processing tasks. These
lecture notes will present a brief introduction to the basic theoretical
concepts behind this `second quantum revolution.' These notes will also provide
an introduction to `circuit QED.' In addition to being a novel test bed for
non-linear quantum optics of microwave electrical circuits which use
superconducting qubits as artificial atoms, circuit QED offers an architecture
for constructing quantum information processors.
