Vortex qubit based on an annular Josephson junction containing a microshort
A. N. Price, A. Kemp, D. R. Gulevich +2 more
We report theoretical and experimental work on the development of a vortex qubit based on a microshort in an annular Josephson junction. The microshort creates a potential barrier for the vortex, which produces a double-well potential under the application of an in-plane magnetic field; the field strength tunes the barrier height. A one-dimensional model for this system is presented, from which we calculate the vortex-depinning current and attempt frequency as well as the interwell coupling. Implementation of an effective microshort is achieved via a section of insulating barrier that is locally wider in the junction plane. Using a junction with this geometry we demonstrate classical state preparation and readout. The vortex is prepared in a given potential well by sending a series of ``shaker'' bias-current pulses through the junction. Readout is accomplished by measuring the vortex-depinning current.
arXiv:0807.0488•Physical Review B•Jan 8, 2010•20 citations