title: Direct observation of coherent population trapping in a superconducting artificial atom.
abstract: The phenomenon of coherent population trapping (CPT) of an atom (or solid state "artificial atom"), and the associated effect of electromagnetically induced transparency (EIT), are clear demonstrations of quantum interference due to coherence in multilevel quantum systems. We report observation of CPT in a superconducting phase qubit by simultaneously driving two coherent transitions in a Lambda-type configuration, utilizing the three lowest lying levels of a local minimum of a phase qubit. We observe 60(+/-7)% suppression of the excited state population under conditions of CPT resonance. We present data and matching theoretical simulations showing the development of CPT in time. Finally, we used the observed time dependence of the excited state population to characterize quantum dephasing times of the system.
authors.affiliation: Raytheon BBN Technologies, Cambridge, Massachusetts 02138, USA. wkelly@bbn.com
authors.forename: William R
authors.initials: WR
authors.lastname: Kelly
authors.forename: Zachary
authors.initials: Z
authors.lastname: Dutton
authors.forename: John
authors.initials: J
authors.lastname: Schlafer
authors.forename: Bhaskar
authors.initials: B
authors.lastname: Mookerji
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Ohki
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Kline
authors.forename: David P
authors.initials: DP
authors.lastname: Pappas