Using macroscopic entanglement to close the detection loophole in Bell inequality

Abstract

We consider a Bell-like inequality performed using various instances of multi-photon entangled states to demonstrate that losses occurring after the unitary transformations used in the nonlocality test can be counteracted by enhancing the "size" of such entangled states. In turn, this feature can be used to overcome detection inefficiencies affecting the test itself: a slight increase in the size of such states, pushing them towards a more "macroscopic" form of entanglement, significantly improves the state robustness against detection inefficiency, thus easing the closing of the detection loophole. Differently, losses before the unitary transformations cause decoherence effects that cannot be compensated using macroscroscopic entanglement.

5 pages, 5 figures, to be published in Phys. Rev. A

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Cited by in corpus (14)

• Coarsening Measurement References and the Quantum-to-Classical Transition
• Violation of Bell-CHSH inequality using imperfect photodetectors with optical hybrid states
• Characterizations and Quantifications of Macroscopic Quantumness and Its Implementations using Optical Fields
• Efficient noiseless linear amplification for light fields with larger amplitudes
• Closing the detection loophole in multipartite Bell tests using GHZ states
• Bell inequality tests using asymmetric entangled coherent states in asymmetric lossy environments
• Closing the detection loophole in tripartite Bell tests using the W state
• Beating detection loophole in nonlinear entanglement witnesses
• Detection loophole in measurement-device-independent entanglement witness
• Noisy quantum input loophole in measurement-device-independent entanglement witnesses
• Correlations in local measurements and entanglement in many-body systems
• Closing loopholes of measurement-device-independent nonlinear entanglement witnesses
• Degree of Fuzziness in Coarsened Measurement References
• Effects of the detection loophole on rival entanglement attestation techniques