Sequential Sharing of Quantum Nonlocality via Projective Measurements

Area of Science:

• Quantum Information Science
• Quantum Foundations

Background:

• Sequential sharing of quantum nonlocality is crucial for multiparty collaborative information processing.
• Previous methods typically relied on unsharp measurements.

Purpose of the Study:

• To experimentally demonstrate sequential sharing of quantum nonlocality using only projective measurements.
• To explore the role of classical randomness in observing quantum nonlocality.

Main Methods:

• Utilized projective measurements and classical randomness in a bipartite quantum system.
• Extended the protocol to a tripartite system using Greenberger-Horne-Zeilinger states.
• Experimentally prepared and measured three-photon entangled states.

Main Results:

• Achieved sequential violations of the Clauser-Horne-Shimony-Holt inequality.
• Observed sequential tripartite nonlocality with violations of the Mermin inequality.
• Demonstrated that projective measurements are key to sequential nonlocality sharing.

Conclusions:

• Projective measurements, combined with classical randomness, can realize sequential sharing of quantum nonlocality.
• This provides a new experimental approach for measuring quantum nonlocality.
• Opens technological pathways for distributed quantum networks.