- document
-
De Lange, G. (author), Riste, D. (author), Tiggelman, M.J. (author), Eichler, C. (author), Tornberg, L. (author), Johansson, G. (author), Wallraff, A. (author), Schouten, R.N. (author), DiCarlo, L. (author)We demonstrate the active suppression of transmon qubit dephasing induced by dispersive measurement, using parametric amplification and analog feedback. By real-time processing of the homodyne record, the feedback controller reverts the stochastic quantum phase kick imparted by the measurement on the qubit. The feedback operation matches a model...journal article 2014
- document
-
Groen, J.P. (author), Riste, D. (author), Tornberg, L. (author), Cramer, J. (author), De Groot, P.C. (author), Picot, T. (author), Johansson, G. (author), DiCarlo, L. (author)We realize indirect partial measurement of a transmon qubit in circuit quantum electrodynamics by interaction with an ancilla qubit and projective ancilla measurement with a dedicated readout resonator. Accurate control of the interaction and ancilla measurement basis allows tailoring the measurement strength and operator. The tradeoff between...journal article 2013
- document
-
Riste, D. (author), Bultink, C.C. (author), Tiggelman, M.J. (author), Schouten, R.N. (author), Lehnert, K.W. (author), DiCarlo, L. (author)The tunnelling of quasiparticles across Josephson junctions in superconducting quantum circuits is an intrinsic decoherence mechanism for qubit degrees of freedom. Understanding the limits imposed by quasiparticle tunnelling on qubit relaxation and dephasing is of theoretical and experimental interest, particularly as improved understanding of...journal article 2013
- document
-
Riste, D. (author), Bultink, C.C. (author), Lehnert, K.W. (author), DiCarlo, L. (author)We demonstrate feedback control of a superconducting transmon qubit using discrete, projective measurement and conditional coherent driving. Feedback realizes a fast and deterministic qubit reset to a target state with 2.4% error averaged over input superposition states, and allows concatenating experiments more than 10 times faster than by...journal article 2012
- document
-
Riste, D. (author), Van Leeuwen, J.G. (author), Ku, H.S. (author), Lehnert, K.W. (author), DiCarlo, L. (author)We demonstrate initialization by joint measurement of two transmon qubits in 3D circuit quantum electrodynamics. Homodyne detection of cavity transmission is enhanced by Josephson parametric amplification to discriminate the two-qubit ground state from single-qubit excitations nondestructively and with 98.1% fidelity. Measurement and...journal article 2012
- document
-
Wang, Z.H. (author), De Lange, G. (author), Riste, D. (author), Hanson, R. (author), Dobrovitski, V.V. (author)We perform a detailed theoretical-experimental study of the dynamical decoupling (DD) of the nitrogen-vacancy (NV) center in diamond. We investigate the DD sequences applied to suppress the dephasing of the electron spin of the NV center induced by the coupling to a spin bath composed of the substitutional nitrogen atoms. The decoupling...journal article 2012