Experimental study of ballistic fluxon detectors for superconducting qubits
Final Report Abstract
The main result obtained within this project is the experimental implementation of a readout of a superconducting flux qubit by a Josephson fluxon. We believe that this demonstration of principle opens vvay to experiments with superconducting qubits controlled by RSFQ logic and, potentially, lead to a scalable quantum computer. The accompanying result on the propagating fluxon scattering on the current dipole uncovers an interesting and nontrivial problem of relativistic interaction betvreen the .Josephson vortex and inhomogeneities in long Josephson junctions. The technique of fluxon frequency detection, developed in the presented experiments, provides an excellent experimental tool to study fluxon physics. The other results on fluxon pinning in disordered Josephson arrays and on nonreciprocal microwave transmission through long Josephson junctions in flux-flow regime are also of practical interest, though they extend beyond the original focus of the project.
Publications
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Pinning of charge and flux solitons in disordered Josepkson junction arrays, Phys. Rev. B 84, 014526 (2011)
K.G. Fedorov, M.V. Fistul, A.V. Ustinov
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Nonreciprocal microwave transmission through a long Josephson junction, Phys. Rev. B 85, 184512 (2012)
K.G. Fedorov, S.V. Shitov, H. Rotzinger, A.V. Ustinov
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Fluxon readout of a superconducting qubit
K.G. Fedorov, A. Shcherbakova, M.J. Wolf, D. Beckmann, A.V. Ustinov
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Josephson vortex coupled to a flux qubit, Appl. Phys. Lett. 102, 132602 (2013)
K.G. Fedorov, A. Shcherbakova, R. Schäfer, A.V. Ustinov
