Bell Inequality Tests with Macroscopic Entangled States of Light

Abstract

Quantum correlations may violate the Bell inequalities. Most of the experimental schemes confirming this prediction have been realized in all-optical Bell tests suffering from the detection loophole. Experiment which closes this loophole and the locality loophole simultaneously is highly desirable and remains challenging. A novel approach to a loophole-free Bell tests is based on amplification of the entangled photons, i.e.\@ on macroscopic entanglement, which optical signal should be easy to detect. However, the macroscopic states are partially indistinguishable by the classical detectors. An interesting idea to overcome these limitations is to replace the postselection by an appropriate preselection immediately after the amplification. This is in the spirit of state preprocessing revealing hidden nonlocality. Here, we examine one of possible preselections, but the presented tools can be used for analysis of other schemes. Filtering methods making the macroscopic entanglement useful for Bell test and quantum protocols are the subject of an intensive study in the field nowadays.

4 pages

References in corpus (4)

• Schroedinger Cat: Entanglement test in a Micro-Macroscopic system
• Quantum experiments with human eyes as detectors based on cloning via stimulated emission
• Quantum to classical transition via fuzzy measurements on high gain spontaneous parametric down-conversion
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• Using macroscopic entanglement to close the detection loophole in Bell inequality
• Interference of macroscopic beams on a beam splitter: phase uncertainty converted into photon-number uncertainty
• Efficient Amplification of Photonic Qubits by Optimal Quantum Cloning
• Proposal for distribution of multi-photon entanglement with optimal rate-distance scaling
• Towards loophole-free Bell inequality test with preselected unsymmetrical singlet states of light
• Nonlinear Bell inequality for macroscopic measurements
• Numerical model for macroscopic quantum superpositions based on phase-covariant quantum cloning
• Multi-photon quantum interference with high visibility using multiport beam splitters
• CHSH Bell Tests For Optical Hybrid Entanglement
• Feasible quantum engineering of quantum multiphoton superpositions
• Loss-tolerant hybrid measurement test of CHSH inequality with weakly amplified N00N states