title: Current to frequency conversion in a Josephson circuit.
abstract: The voltage oscillations which occur in an ideally current-biased Josephson junction were proposed to make a current standard for metrology. We demonstrate similar oscillations in a more complex Josephson circuit derived from the Cooper pair box: the quantronium. When a constant current I is injected in the gate capacitor of this device, oscillations develop at the frequency f(B)=I/2e, with e the electron charge. We detect these oscillations through the sidebands induced at multiples of f(B) in the spectrum of a microwave signal reflected on the circuit, up to currents I exceeding 100 pA. We discuss the potential interest of this current-to-frequency conversion experiment for metrology.
authors.affiliation: Quantronics Group, Service de Physique de l'Etat Condensé (CNRS URA 2464), DSM/DRECAM/SPEC, CEA-Saclay, 91191 Gif-sur-Yvette, France.
authors.forename: F
authors.initials: F
authors.lastname: Nguyen
authors.forename: N
authors.initials: N
authors.lastname: Boulant
authors.forename: G
authors.initials: G
authors.lastname: Ithier
authors.forename: P
authors.initials: P
authors.lastname: Bertet
authors.forename: H
authors.initials: H
authors.lastname: Pothier
authors.forename: D
authors.initials: D
authors.lastname: Vion
authors.forename: D
authors.initials: D
authors.lastname: Esteve