Quantum trajectory approach to circuit QED: Quantum jumps and the Zeno effect

Jay Gambetta, Alexandre Blais, M. Boissonneault, A. A. Houck, D. I. Schuster, S. M. Girvin

Research output: Contribution to journalArticle

170 Scopus citations

Abstract

We present a theoretical study of a superconducting charge qubit dispersively coupled to a transmission line resonator. Starting from a master equation description of this coupled system and using a polaron transformation, we obtain an exact effective master equation for the qubit. We then use quantum trajectory theory to investigate the measurement of the qubit by continuous homodyne measurement of the resonator out field. Using the same polaron transformation, a stochastic master equation for the conditional state of the qubit is obtained. From this result, various definitions of the measurement time are studied. Furthermore, we find that in the limit of strong homodyne measurement, typical quantum trajectories for the qubit exhibit a crossover from diffusive to jumplike behavior. Finally, in the presence of Rabi drive on the qubit, the qubit dynamics is shown to exhibit quantum Zeno behavior.

Original languageEnglish (US)
Article number012112
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume77
Issue number1
DOIs
StatePublished - Jan 25 2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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