title: Nonlinear single-spin spectrum analyzer.
abstract: Qubits have been used as linear spectrum analyzers of their environments. Here we solve the problem of nonlinear spectral analysis, required for discrete noise induced by a strongly coupled environment. Our nonperturbative analytical model shows a nonlinear signal dependence on noise power, resulting in a spectral resolution beyond the Fourier limit as well as frequency mixing. We develop a noise characterization scheme adapted to this nonlinearity. We then apply it using a single trapped ion as a sensitive probe of strong, non-Gaussian, discrete magnetic field noise. Finally, we experimentally compared the performance of equidistant vs Uhrig modulation schemes for spectral analysis.
authors.affiliation: Department of Physics of Complex Systems, Weizmann Institute of Science, P. O. Box 26, Rehovot 76100, Israel.
authors.forename: Shlomi
authors.initials: S
authors.lastname: Kotler
authors.affiliation: Department of Physics of Complex Systems, Weizmann Institute of Science, P. O. Box 26, Rehovot 76100, Israel.
authors.forename: Nitzan
authors.initials: N
authors.lastname: Akerman
authors.affiliation: Department of Physics of Complex Systems, Weizmann Institute of Science, P. O. Box 26, Rehovot 76100, Israel.
authors.forename: Yinnon
authors.initials: Y
authors.lastname: Glickman
authors.affiliation: Department of Physics of Complex Systems, Weizmann Institute of Science, P. O. Box 26, Rehovot 76100, Israel.
authors.forename: Roee
authors.initials: R
authors.lastname: Ozeri