Interaction-Free Measurement of a Quantum Object: On the Breeding of “Schrödinger Cats”

  • Paul G. Kwiat
  • Harald Weinfurter
  • Anton Zeilinger

Abstract

The possibility of an “interaction-free” determination of the presence of an object was first discussed by Renninger and by Dicke,1 who examined the effect on a quantum system due to the non-observation of a particular result (e.g., the non-scattering of a photon). Elitzur and Vaidman extended these ideas, so that the presence of an object modified the interference of a photon, even though the photon and object need not have interacted.2 In the best case, their method works only 50% of the time. We have recently reported a different technique,3 based on the quantum Zeno effect,4 which allows the fraction of interaction-free measurements (IFMs) to be arbitrarily close to 1. As a result, one even has the possibility to employ multi-photon pulses for the interrogation. When the object being observed is in a quantum superposition state, one can prepare superpositions and entanglements of these macroscopic states of light.

Keywords

Coherent State Entangle State Quantum Object Macroscopic State Coupling Path 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1996

Authors and Affiliations

  • Paul G. Kwiat
    • 1
  • Harald Weinfurter
    • 1
  • Anton Zeilinger
    • 1
  1. 1.Institut für ExperimentalphysikUniversität InnsbruckInnsbruckAustria

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