Félix Beaudoin, Jay M. Gambetta, et al.
Physical Review A - AMO
We study bifurcation measurement of a multilevel superconducting qubit using a nonlinear resonator biased in the straddling regime, where the resonator frequency sits between two qubit transition frequencies. We find that high-fidelity bifurcation measurements are possible because of the enhanced qubit-state-dependent pull of the resonator frequency, the behavior of qubit-induced nonlinearities, and the reduced Purcell decay rate of the qubit that can be realized in this regime. Numerical simulations find up to a threefold improvement in qubit readout fidelity when operating in, rather than outside of, the straddling regime. High-fidelity measurements can be obtained at much smaller qubit-resonator couplings than current typical experimental realizations, reducing spectral crowding and potentially simplifying the implementation of multiqubit devices. © 2012 American Physical Society.
Félix Beaudoin, Jay M. Gambetta, et al.
Physical Review A - AMO
Antonio D. Córcoles, Abhinav Kandala, et al.
Proceedings of the IEEE
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npj Quantum Information
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Applied Physics Letters