Ramsey-biased spectroscopy of superconducting qubits under dispersion

Abstract

We proposed a spectroscopic method that extends Ramsey's atomic spectroscopy to detect the transition frequency of a qubit fabricated on a superconducting circuit. The method uses a multi-interval train of qubit biases to implement an alternate resonant and dispersive couplings to an incident probe field. The consequent absorption spectrum of the qubit has a narrower linewidth at its transition frequency than that obtained from constantly biasing the qubit to resonance while the middle dispersive evolution incurs only a negligible shift in detected frequency. Modeling on transmon qubits, we find that the linewidth reduction reaches 23% and Ramsey fringes are simultaneously suppressed at extreme duration ratio of dispersion over resonance for a double-resonance scheme. If the scheme is augmented by an extra resonance segment, a further 37% reduction can be achieved.

References in corpus (7)

• Charge insensitive qubit design derived from the Cooper pair box
• Coupling Superconducting Qubits via a Cavity Bus
• Superconducting Circuits and Quantum Information
• Suppressing Charge Noise Decoherence in Superconducting Charge Qubits
• Dressed Collective Qubit States and the Tavis-Cummings Model in Circuit QED
• Two-Qubit State Tomography using a Joint Dispersive Read-Out
• Resonant excitations of single and two-qubit systems coupled to a tank circuit