Nonlinear resonant behavior of the dispersive readout scheme for a superconducting flux qubit

Abstract

A nonlinear resonant circuit comprising a SQUID magnetometer and a parallel capacitor is studied as a readout scheme for a persistent-current (PC) qubit. The flux state of the qubit is detected as a change in the Josephson inductance of the SQUID magnetometer, which in turn mediates a shift in the resonance frequency of the readout circuit. The nonlinearity and resulting hysteresis in the resonant behavior are characterized as a function of the power of both the input drive and the associated resonance peak response. Numerical simulations based on a phenomenological circuit model are presented which display the features of the observed nonlinearity.

9 pages, 9 figures

References in corpus (5)

• Approaching Unit Visibility for Control of a Superconducting Qubit with Dispersive Readout
• Coherent Quasiclassical Dynamics of a Persistent Current Qubit
• High-contrast dispersive readout of a superconducting flux qubit using a nonlinear resonator
• Low-frequency measurement of the tunneling amplitude in a flux qubit
• Coherent control of a flux qubit by phase-shifted resonant microwave pulses

Cited by in corpus (7)

• Large-amplitude driving of a superconducting artificial atom: Interferometry, cooling, and amplitude spectroscopy
• Fabrication and measurements of hybrid Nb/Al Josephson junctions and flux qubits with pi-shifters
• Quantum analysis of a nonlinear microwave cavity-embedded dc SQUID displacement detector
• Dynamical tunneling in macroscopic systems
• Weak and strong measurement of a qubit using a switching-based detector
• Displacement Detection with a Vibrating RF SQUID: Beating the Standard Linear Limit
• Thermal conductance of Nb thin films at sub-kelvin temperatures