Busch, Paul
(2003)
*Quantum States and Generalized Observables: A Simple Proof of Gleason's Theorem.*
Physical Review Letters, 91 (12/120).
pp. 1-4.
ISSN 1079-7114

## Abstract

A quantum state can be understood in a loose sense as a map that assigns a value to every observable. Formalizing this characterization of states in terms of generalized probability distributions on the set of effects, we obtain a simple proof of the result, analogous to Gleason’s theorem, that any quantum state is given by a density operator. As a corollary we obtain a von Neumann–type argument against noncontextual hidden variables. It follows that on an individual interpretation of quantum mechanics the values of effects are appropriately understood as propensities.

Item Type: | Article |
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Institution: | The University of York |

Academic Units: | The University of York > Mathematics (York) |

Depositing User: | York RAE Import |

Date Deposited: | 23 Feb 2009 15:31 |

Last Modified: | 27 Apr 2010 09:36 |

Published Version: | http://dx.doi.org/10.1103/PhysRevLett.91.120403 |

Status: | Published |

Publisher: | The American Physical Society. |

Identification Number: | 10.1103/PhysRevLett.91.120403 |

URI: | http://eprints.whiterose.ac.uk/id/eprint/7250 |