Dispersive magnetometry with a quantum limited SQUID parametric amplifier

By M. Hatridge, R. Vijay, D. Slichter, John Clarke, Irfan Siddiqi. 2010

250 citations recorded by the source corpus.

Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, CA 94720There is currently fundamental and technological interest in measuring and manipulatingnanoscale magnets, particularly in the quantum coherent regime. To observe the dynamics ofsuch systems one requires a magnetometer with not only exceptional sensitivity but also high gain,wide bandwidth and low backaction. We demonstrate a dispersive magnetometer consisting of atwo-junction SQUID in parallel with an integrated, lumped-element capacitor. Input ux signals areencoded as a phase modulation of the microwave drive tone applied to the magnetometer, resultingin a single quadrature voltage signal. For strong drive power, the nonlinearity of the resonatorresults in quantum limited, phase sensitive parametric ampli cation of this signal, which improvesux sensitvity at the expense of bandwidth. Depending on the drive parameters, the device per-formance ranges from an e ective ux noise of 0.29

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/18331a8daf96a75c7030357a2c2b93f74a37e139