FAST TRACK COMMUNICATION: A simple test of quantumness for a single system
Abstract
We propose a simple test of quantumness which can decide whether for a given set of accessible experimental data the classical model is insufficient. Take two observables A, B such that for all states ψ their mean values satisfy 0 <= langψ|A|ψrang <= langψ|B|ψrang <= 1. If there exists a state phi such that the second moments fulfill the inequality langphi|A2|phirang > langphi|B2|phirang then the system cannot be described by a classical probabilistic scheme. An example of an optimal triple (A, B, phi) in the case of a qubit is given.
- Publication:
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Journal of Physics A Mathematical General
- Pub Date:
- February 2008
- DOI:
- 10.1088/1751-8113/41/6/062001
- arXiv:
- arXiv:0704.1962
- Bibcode:
- 2008JPhA...41f2001A
- Keywords:
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- Quantum Physics
- E-Print:
- 3 pages, no figures, corrected typos, text essentially amended