title: Time-resolved measurement of dissipation-induced decoherence in a Josephson junction.
abstract: We determined the dissipation-induced decoherence time (DIDT) of a superconducting Josephson tunnel junction by time-resolved measurements of its escape dynamics. Double-exponential behavior of the time-dependent escape probability was observed, suggesting the occurrence of a two-level decay-tunneling process in which energy relaxation from the excited to the ground level significantly affects the escape dynamics of the system. The observation of temporal double-exponential dependence enables direct measurements of the DIDT, a property critical to the study of quantum dynamics and the realization of macroscopic quantum coherence and quantum computing. We found that the DIDT was tau(d) > 11 micros at T = 0.55 K, demonstrating good prospects for implementing quantum computing with Josephson devices.
authors.affiliation: Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045, USA. han@ku.edu
authors.forename: S
authors.initials: S
authors.lastname: Han
authors.forename: Y
authors.initials: Y
authors.lastname: Yu
authors.forename: X
authors.initials: X
authors.lastname: Chu
authors.forename: S I
authors.initials: SI
authors.lastname: Chu
authors.forename: Z
authors.initials: Z
authors.lastname: Wang