Enhanced estimation of quantum evolution parameters with entangled states

ORAL

Abstract

Quantum estimation considers the issue of estimating parameters associated with the description of a quantum state or of the evolution of a quantum state when only a finite number of copies of the quantum system are available. The accuracy of any estimation scheme is limited by both standard statistical sampling issues as well as the inherent statistical nature of measurement outcomes for quantum systems. We consider rotations of a spin-1/2 particle about a fixed axis and which are parametrized by a rotation angle, which is to be estimated. We use the quantum Fisher information to establish optimal bounds on the variance in any estimator of this parameter in scenarios involving one use of the rotation upon each of a collection of spin-1/2 particles. We show that optimal estimation occurs when all spin-1/2 particles are entangled and present exact analytical results for the bound that is generated and the required input state. We show that this offers a significant advantage over the use of unentangled states.

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Authors

  • John Poate

    Brigham Young University, Los Alamos National Laboratory, Department of Physics and Astronomy, University of Utah, USA, MV Systems, Inc., USA, Helmholtz-Zentrum Berlin fuer Materialien und Energie, Abteilung Silizium-Photovoltaik, Germany, Colorado School of Mines, Department of Physics, USA, Georgia Institute of Technology, Arizona State University, Physics Department of Babolsar University, Iran, Physics Department, New Mexico State University, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287-1604, USA, Department of Electrical Engineering, University of Arkansas, Fayetteville, AR 72701, USA, Department of Physics, Arizona State University, Tempe, AZ, 85287-1504, USA, Colorado State University, University of Wisconsin, NSF ERC for Extreme Ultraviolet Science and Technology, Colorado State University, BYU-Provo, Michigan Technical University and Pierre Auger Collaboration, University of Colorado, Colorado School of Mines, Department of Physics, Colorado State University, Department of Physics, Cornell University, NASA, University of Massachusetts at Amherst, University of Massachusetss at Amherst, APS President, Harvard University, Society of Physics Students, Duke University, Computer Science, Brigham Young University, Chemistry \& Biochemistry, Brigham Young University, University of Arizona, University of Utah, Kansas State Univ., Bethel University, University of New Mexico, Stanford University, JILA, University of Colorado at Boulder, NIST, JILA, University of Colorado at Boulder, National Renewable Energy Laboratory, University of Denver, University of Colorado, Boulder, NREL, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287- 1604, USA, DU, ERI, Eleanor Roosevelt Institute (ERI), Cerro Tololo Interamerican Observatory, Utah State University, Center for Atmospheric and Space Sciences, Sciprint.org, University of Colorado at Boulder, JILA and University of Colorado, Kirchhoff Institute for Physics, University of Heidelberg, Utah Valley University, University of New South Wales, San Francisco State University, Weber State University, Cambridge University, Department of Physics and Astronomy, University of Utah, Kansas State University, Columbia University, NY, University of Colorado/JILA, Vice-President for Research and Technology Transfer, Colorado School of Mines

  • John Poate

    Brigham Young University, Los Alamos National Laboratory, Department of Physics and Astronomy, University of Utah, USA, MV Systems, Inc., USA, Helmholtz-Zentrum Berlin fuer Materialien und Energie, Abteilung Silizium-Photovoltaik, Germany, Colorado School of Mines, Department of Physics, USA, Georgia Institute of Technology, Arizona State University, Physics Department of Babolsar University, Iran, Physics Department, New Mexico State University, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287-1604, USA, Department of Electrical Engineering, University of Arkansas, Fayetteville, AR 72701, USA, Department of Physics, Arizona State University, Tempe, AZ, 85287-1504, USA, Colorado State University, University of Wisconsin, NSF ERC for Extreme Ultraviolet Science and Technology, Colorado State University, BYU-Provo, Michigan Technical University and Pierre Auger Collaboration, University of Colorado, Colorado School of Mines, Department of Physics, Colorado State University, Department of Physics, Cornell University, NASA, University of Massachusetts at Amherst, University of Massachusetss at Amherst, APS President, Harvard University, Society of Physics Students, Duke University, Computer Science, Brigham Young University, Chemistry \& Biochemistry, Brigham Young University, University of Arizona, University of Utah, Kansas State Univ., Bethel University, University of New Mexico, Stanford University, JILA, University of Colorado at Boulder, NIST, JILA, University of Colorado at Boulder, National Renewable Energy Laboratory, University of Denver, University of Colorado, Boulder, NREL, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287- 1604, USA, DU, ERI, Eleanor Roosevelt Institute (ERI), Cerro Tololo Interamerican Observatory, Utah State University, Center for Atmospheric and Space Sciences, Sciprint.org, University of Colorado at Boulder, JILA and University of Colorado, Kirchhoff Institute for Physics, University of Heidelberg, Utah Valley University, University of New South Wales, San Francisco State University, Weber State University, Cambridge University, Department of Physics and Astronomy, University of Utah, Kansas State University, Columbia University, NY, University of Colorado/JILA, Vice-President for Research and Technology Transfer, Colorado School of Mines