  We propose a superconducting qubit design, based on a tunable RF-SQUID and
nanowire kinetic inductors, which has a dramatically reduced transverse
electromagnetic coupling to its environment, so that its excited state should
be metastable. If electromagnetic interactions are in fact responsible for the
current excited-state decay rates of superconducting qubits, this design should
result in a qubit lifetime orders of magnitude longer than currently possible.
Furthermore, since accurate manipulation and readout of superconducting qubits
is currently limited by spontaneous decay, much higher fidelities may be
realizable with this design.
