Undoing a Weak Quantum Measurement of a Solid-State Qubit

Alexander N. Korotkov and Andrew N. Jordan
Phys. Rev. Lett. 97, 166805 – Published 20 October 2006

Abstract

We propose an experiment which demonstrates the undoing of a weak continuous measurement of a solid-state qubit, so that any unknown initial state is fully restored. The undoing procedure has only a finite probability of success because of the nonunitary nature of quantum measurement, though it is accompanied by a clear experimental indication of whether or not the undoing has been successful. The probability of success decreases with increasing strength of the measurement, reaching zero for a traditional projective measurement. Measurement undoing (“quantum undemolition”) may be interpreted as a kind of quantum eraser, in which the information obtained from the first measurement is erased by the second measurement, which is an essential part of the undoing procedure. The experiment can be realized using quantum dot (charge) or superconducting (phase) qubits.

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  • Received 6 July 2006

DOI:https://doi.org/10.1103/PhysRevLett.97.166805

©2006 American Physical Society

Authors & Affiliations

Alexander N. Korotkov1 and Andrew N. Jordan2,3

  • 1Department of Electrical Engineering, University of California, Riverside, California 92521-0204, USA
  • 2Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
  • 3Institute for Quantum Studies, Texas A&M University, College Station, Texas 77843-4242, USA

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Issue

Vol. 97, Iss. 16 — 20 October 2006

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