arXiv:1009.4470 · Physical Review Letters

Superconducting Qubit with Purcell Protection and Tunable Coupling

Jay Gambetta, Andrew Houck, Alexandre Blais

Published Jan 20, 2011• 128 citations

Abstract

We present a superconducting qubit for the circuit quantum electrodynamics architecture that has a tunable qubit-resonator coupling strength g. This coupling can be tuned from zero to values that are comparable with other superconducting qubits. At g = 0, the qubit is in a decoherence-free subspace with respect to spontaneous emission induced by the Purcell effect. Furthermore, we show that in this decoherence-free subspace, the state of the qubit can still be measured by either a dispersive shift on the resonance frequency of the resonator or by a cycling-type measurement.

DOI: 10.1103/physrevlett.106.030502

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