title: Decoherence dynamics of complex photon states in a superconducting circuit.
abstract: Quantum states inevitably decay with time into a probabilistic mixture of classical states due to their interaction with the environment and measurement instrumentation. We present the first measurement of the decoherence dynamics of complex photon states in a condensed-matter system. By controllably preparing a number of distinct quantum-superposed photon states in a superconducting microwave resonator, we show that the subsequent decay dynamics can be quantitatively described by taking into account only two distinct decay channels: energy relaxation and pure dephasing. Our ability to prepare specific initial quantum states allows us to measure the evolution of specific elements in the quantum density matrix in a very detailed manner that can be compared with theory.
authors.affiliation: Department of Physics, University of California, Santa Barbara, California 93106, USA.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Hofheinz
authors.forename: M
authors.initials: M
authors.lastname: Ansmann
authors.forename: R C
authors.initials: RC
authors.lastname: Bialczak
authors.forename: Erik
authors.initials: E
authors.lastname: Lucero
authors.forename: M
authors.initials: M
authors.lastname: Neeley
authors.forename: A D
authors.initials: AD
authors.lastname: O'Connell
authors.forename: D
authors.initials: D
authors.lastname: Sank
authors.forename: M
authors.initials: M
authors.lastname: Weides
authors.forename: J
authors.initials: J
authors.lastname: Wenner
authors.forename: A N
authors.initials: AN
authors.lastname: Cleland
authors.forename: John M
authors.initials: JM
authors.lastname: Martinis