Effect of noise and enhancement of nonlocality in on/off photodetection
- Dipartimento di Fisica dell'Universita degli Studi, Milan (Italy)
Nonlocality of two-mode states of light is addressed by means of Clauser-Horne-Shimony-Holt (CHSH) inequality based on displaced on/off photodetection. Effects due to nonunit quantum efficiency and nonzero dark counts are taken into account. Nonlocality of both balanced and unbalanced superpositions of few photon-number states, as well as that of multiphoton twin beams, is investigated. We find that unbalanced superpositions show larger nonlocality than balanced ones when noise affects the photodetection process. De-Gaussification by means of (inconclusive) photon subtraction is shown to enhance nonlocality of twin beams in the low-energy regime. We also show that when the measurement is described by a positive operator-valued measure, rather than a set of projectors, the maximum achievable value of the Bell parameter in the CHSH inequality is decreased, and is no longer given by the Cirel'son bound.
- OSTI ID:
- 20718685
- Journal Information:
- Physical Review. A, Vol. 72, Issue 4; Other Information: DOI: 10.1103/PhysRevA.72.042105; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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