Ambiguous measurements, signaling, and violations of Leggett-Garg inequalities

Emary, Clive

Abstract

Ambiguous measurements do not reveal complete information about the system under test. Their quantum-mechanical counterparts are semiweak (or in the limit, weak) measurements and here we discuss their role in tests of the Leggett-Garg inequalities. We show that, while ambiguous measurements allow one to forgo the usual noninvasive measurability assumption, to derive a Leggett-Garg inequality that may be violated, we are forced to introduce another assumption that equates the invasive influence of ambiguous and unambiguous detectors. Based on this assumption, we derive signaling conditions that should be fulfilled for the plausibility of the Leggett-Garg test. We then propose an experiment on a three-level system with a direct quantum-optics realization that satisfies all signaling constraints and violates a Leggett-Garg inequality.

Citation

Emary, C. (2017). Ambiguous measurements, signaling, and violations of Leggett-Garg inequalities. Physical Review A, 96(4), Article 042102. https://doi.org/10.1103/PhysRevA.96.042102

• Journal Article Type: Article
• Acceptance Date: Apr 2, 2016
• Online Publication Date: Oct 4, 2017
• Publication Date: Oct 4, 2017
• Deposit Date: Jun 28, 2018
• Publicly Available Date: Jul 5, 2018
• Journal: Physical Review A
• Print ISSN: 2469-9926
• Electronic ISSN: 2469-9934
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 96
• Issue: 4
• Article Number: 042102
• DOI: https://doi.org/10.1103/PhysRevA.96.042102
• Public URL: https://hull-repository.worktribe.com/output/898303
• Publisher URL: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.96.042102
• Related Public URLs: https://eprint.ncl.ac.uk/241957