Macroscopic Observables

  title={Macroscopic Observables},
  author={D. Poulin},
  journal={Physical Review A},
  • D. Poulin
  • Published 2004
  • Physics
  • Physical Review A
We study macroscopic observables defined as the total value of a physical quantity over a collection of quantum systems. We show that previous results obtained for an infinite ensemble of identically prepared systems lead to incorrect conclusions for finite ensembles. In particular, exact measurement of a macroscopic observable significantly disturbs the state of any finite ensemble. However, we show how this disturbance can be made arbitrarily small when the measurements are of finite accuracy… Expand
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