Genuine multipartite nonlocality with causal-diagram postselection

Abstract

The generation and verification of genuine multipartite nonlocality (GMN) is of central interest for both fundamental research and quantum technological applications, such as quantum privacy. To demonstrate GMN in measurement data, the statistics are commonly postselected by neglecting undesired data. Until now, valid postselection strategies have been restricted to local postselection. A general postselection that is decided after communication between parties can mimic nonlocality, even though the complete data are local. Here, we establish conditions under which GMN is demonstrable even if observations are postselected collectively. Intriguingly, certain postselection strategies that require communication among several parties still offer a demonstration of GMN shared between all parties. The results are derived using the causal structure of the experiment and the no-signalling condition imposed by relativity. Finally, we apply our results to show that genuine three-partite nonlocality can be created with independent particle sources.

References in corpus (8)

• The Quantum Internet
• Device-independent security of quantum cryptography against collective attacks
• Secure device-independent quantum key distribution with causally independent measurement devices
• Private Randomness Expansion With Untrusted Devices
• Quantifying multipartite nonlocality
• Proposed Bell experiment with genuine energy-time entanglement
• Metrological Detection of Multipartite Entanglement from Young Diagrams
• Bell Experiments with Random Destination Sources

Cited by in corpus (9)

• Single-photon nonlocality in quantum networks
• Experimental nonclassicality in a causal network without assuming freedom of choice
• Experimental demonstration of genuine tripartite nonlocality under strict locality conditions
• Shortcut to Multipartite Entanglement Generation: A Graph Approach to Boson Subtractions
• Coincidence postselection for genuine multipartite nonlocality: Causal diagrams and threshold efficiencies
• Verifying Hierarchic Multipartite and Network Nonlocalities with a Unified Method
• Extending the fair sampling assumption using causal diagrams
• Creating nonlocality using geometric phases between partially distinguishable photons
• Testing Genuine Multipartite Nonlocality via an Inflated Network with Multi-copy Entangled States