  We propose a realizable architecture using one-dimensional transmission line
resonators to reach the strong coupling limit of cavity quantum electrodynamics
in superconducting electrical circuits. The vacuum Rabi frequency for the
coupling of cavity photons to quantized excitations of an adjacent electrical
circuit (qubit) can easily exceed the damping rates of both the cavity and the
qubit. This architecture is attractive both as a macroscopic analog of atomic
physics experiments and for quantum computing and control, since it provides
strong inhibition of spontaneous emission, potentially leading to greatly
enhanced qubit lifetimes, allows high-fidelity quantum non-demolition
measurements of the state of multiple qubits, and has a natural mechanism for
entanglement of qubits separated by centimeter distances. In addition it would
allow production of microwave photon states of fundamental importance for
quantum communication.
