title: Direct Wigner tomography of a superconducting anharmonic oscillator.
abstract: The analysis of wave-packet dynamics may be greatly simplified when viewed in phase space. While harmonic oscillators are often used as a convenient platform to study wave packets, arbitrary state preparation in these systems is more challenging. Here, we demonstrate a direct measurement of the Wigner distribution of complex photon states in an anharmonic oscillator--a superconducting phase circuit, biased in the small anharmonicity regime. We apply our method on nondispersive wave packets to explicitly show phase locking in states prepared by a frequency chirp. This method requires a simple calibration, and is easily applicable in our system out to the fifth level.
authors.affiliation: Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Yoni
authors.initials: Y
authors.lastname: Shalibo
authors.forename: Roy
authors.initials: R
authors.lastname: Resh
authors.forename: Ofer
authors.initials: O
authors.lastname: Fogel
authors.forename: David
authors.initials: D
authors.lastname: Shwa
authors.forename: Radoslaw
authors.initials: R
authors.lastname: Bialczak
authors.forename: John M
authors.initials: JM
authors.lastname: Martinis
authors.forename: Nadav
authors.initials: N
authors.lastname: Katz