  Physical implementations of qubits can be extremely sensitive to
environmental coupling, which can result in decoherence. While efforts are made
for protection, coupling to the environment is necessary to measure and
manipulate the state of the qubit. As such, the goal of having long qubit
energy relaxation times is in competition with that of achieving high-fidelity
qubit control and measurement. Here we propose a method that integrates
filtering techniques for preserving superconducting qubit lifetimes together
with the dispersive coupling of the qubit to a microwave resonator for control
and measurement. The result is a compact circuit that protects qubits from
spontaneous loss to the environment, while also retaining the ability to
perform fast, high-fidelity readout. Importantly, we show the device operates
in a regime that is attainable with current experimental parameters and provide
a specific example for superconducting qubits in circuit quantum
electrodynamics.
