Dispersive readout scheme for a Josephson phase qubit

Abstract

We present experimental results on a dispersive scheme for reading out a Josephson phase qubit. A capacitively shunted dc-SQUID is used as a nonlinear resonator which is inductively coupled to the qubit. We detect the flux state of the qubit by measuring the amplitude and phase of a microwave pulse reflected from the SQUID resonator. By this low-dissipative method, we reduce the qubit state measurement time down to 25 microseconds, which is much faster than using the conventional readout performed by switching the SQUID to its non-zero dc voltage state. The demonstrated readout scheme allows for reading out multiple qubits using a single microwave line by employing frequency-division multiplexing.

4 pages, 4 figures

References in corpus (4)

• Nondestructive readout for a superconducting flux qubit
• Temperature dependence of coherent oscillations in Josephson phase qubits
• Nanosecond quantum state detection in a current biased dc SQUID
• Readout for Phase Qubits without Josephson Junctions

Cited by in corpus (7)

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• Circuit QED with fluxonium qubits: theory of the dispersive regime
• Multiplexed dispersive readout of superconducting phase qubits
• Tunable-Cavity QED with Phase Qubits
• Hybrid Electron Spin Resonance and Whispering Gallery Mode Resonance Spectroscopy of Fe3+ in Sapphire
• Transitional dynamics of a phase qubit-resonator system: requirements for fast readout of a phase qubit
• Fine tuning of phase qubit parameters for optimization of fast single-pulse readout