Experimental violation of a Bell-like inequality with optical vortex beams

Optical beams with topological singularities have a Schmidt decomposition. Hence, they display features typically associated with bipartite quantum systems; in particular, these classical beams can exhibit entanglement. This classical entanglement can be quantified by a Bell inequality formulated in...

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Bibliographic Details
Authors: Stoklasa, B., Motka, L., Řeháček, J., Hradil, Z., Sánchez Soto, Luis Lorenzo, Agarwal, Girish S.
Format: article
Publication Date:2015
Country:España
Institution:Universidad Complutense de Madrid (UCM)
Repository:Docta Complutense
Language:English
OAI Identifier:oai:docta.ucm.es:20.500.14352/24324
Online Access:https://hdl.handle.net/20.500.14352/24324
Access Level:Open access
Keyword:535
Orbital angular-momentum
Quantum entanglement
Wigner function
Nonlocality
Coherence
States
Radiometry
Entropy
Fields
Space
Óptica (Física)
2209.19 Óptica Física
Description
Summary:Optical beams with topological singularities have a Schmidt decomposition. Hence, they display features typically associated with bipartite quantum systems; in particular, these classical beams can exhibit entanglement. This classical entanglement can be quantified by a Bell inequality formulated in terms of Wigner functions. We experimentally demonstrate the violation of this inequality for Laguerre-Gauss (LG) beams and confirm that the violation increases with increasing orbital angular momentum. Our experimental scheme, which is designed to give directly the parity of the Wigner function, yields negativity at the origin for LG_10 beams, whereas for LG_20 we always get a positive value.