Suppression of Quantum Fluctuations in a Josephson Junction Coupled to a Nanomechanical Resonator

POSTER

Abstract

The behavior of a Josephson junction (JJ) in parallel with a nanomechanical resonator was studied. The JJ was treated as a particle trapped in a quadratic potential well, and the problem could thus be characterized as two coupled harmonic oscillators. The Feynman path integral technique was used to find the density matrix and partition function for the system. When coupled to the resonator, the square of the uncertainty in the position of the JJ particle was suppressed, i.e. quantum fluctuations of the JJ were reduced by the resonator. The uncertainty principle was obeyed in that the square of the uncertainty in the JJ's momentum was enhanced with resonator coupling. We also included the effects of environmental damping. Damping the junction enhanced the suppression of quantum fluctuations beyond that due to resonator coupling alone. Damping the resonator, however, weakened the effect of JJ-resonator coupling and thus resulted in less suppression of quantum fluctuations. Preliminary results for the effects on quantum fluctuations of a weak nonlinear term in the JJ's potential energy have also been obtained.

Authors

  • Yaser Helal

    Ohio Wesleyan University

  • William H. Rauckhorst

    Gothenburg University, Denison University, Bowling Green State University, NASA Glenn Research Center, Ohio Wesleyan University, Nitronex Corporation, 2305 Presidential Drive, Durham, NC, AFRL/MLPS, Wright-Patterson AFB, OH, Miami University, Ursinus College, Purdue University Calumet, GSI, Florida State University, Carnegie Mellon University, Dept. of Health Sciences, Cleveland State University, Physics Dept., Cleveland State University, University of Rochester, OMI College of Applied Science, University of Cincinnati, Davis and Elkins College, WV, Schlumberger-Doll, Korea Institute of Science and Technology, University of Cincinnati, Lock Haven University of Pennsylvania, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372, Albion College, Albion, MI 49224, University of Toledo, Toledo, OH 43606, Youngstown State University, Joint Institute for Nuclear Research (Dubna), Naval Research Laboratory, ManTech SRS Technologies, Inc., Ecopulse, Inc., Army Research Laboratory, University of Surrey, The Ohio State University, Univ. Akron, Owens Community College, Toledo, OH

  • William H. Rauckhorst

    Gothenburg University, Denison University, Bowling Green State University, NASA Glenn Research Center, Ohio Wesleyan University, Nitronex Corporation, 2305 Presidential Drive, Durham, NC, AFRL/MLPS, Wright-Patterson AFB, OH, Miami University, Ursinus College, Purdue University Calumet, GSI, Florida State University, Carnegie Mellon University, Dept. of Health Sciences, Cleveland State University, Physics Dept., Cleveland State University, University of Rochester, OMI College of Applied Science, University of Cincinnati, Davis and Elkins College, WV, Schlumberger-Doll, Korea Institute of Science and Technology, University of Cincinnati, Lock Haven University of Pennsylvania, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372, Albion College, Albion, MI 49224, University of Toledo, Toledo, OH 43606, Youngstown State University, Joint Institute for Nuclear Research (Dubna), Naval Research Laboratory, ManTech SRS Technologies, Inc., Ecopulse, Inc., Army Research Laboratory, University of Surrey, The Ohio State University, Univ. Akron, Owens Community College, Toledo, OH