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Unbounded Sharing of Nonlocality Using Qubit Projective Measurements
S Sasmal1,2, S Kanjilal3, A K Pan2
1Institute of Fundamental and Frontier Sciences, <a href="https://ror.org/04qr3zq92">University of Electronic Science and Technology of China</a>, Chengdu 611731, China.
Physical Review Letters
|November 12, 2024
Summary
This study shows that local randomness-assisted projective measurements allow arbitrary sequential observers to share quantum nonlocality. This overcomes previous limitations requiring generalized unsharp measurements.
Area of Science:
- Quantum Information Science
- Quantum Foundations
- Quantum Measurement Theory
Background:
- Sequential sharing of quantum nonlocality typically requires generalized unsharp measurements.
- Sharp measurements generally destroy entanglement, hindering nonlocality sharing.
- Prior work showed nonlocality sharing up to two observers using projective measurements with local randomness.
Purpose of the Study:
- To introduce a protocol for unbounded sequential sharing of quantum nonlocality.
- To enable an arbitrary number of observers to share nonlocality with a single source.
- To investigate the role of measurement incompatibility in nonlocality sharing.
Main Methods:
- Development of a local randomness-assisted qubit projective measurement protocol.
- Analysis of generalized measurements that preserve entanglement for nonlocality harnessing.
- Examination of the interplay between measurement incompatibility of sequential observers.
Main Results:
- Demonstration of unbounded sharing of quantum nonlocality among an arbitrary number of sequential observers.
- Preservation of entanglement in the shared two-qubit state through generalized measurements.
- Identification of measurement incompatibility as a key factor for unbounded nonlocality sharing.
Conclusions:
- Projective measurements, aided by local randomness, are sufficient for unbounded sequential sharing of quantum nonlocality.
- The proposed protocol extends nonlocality sharing beyond previous limitations.
- Measurement incompatibility is crucial for achieving and understanding unbounded nonlocality sharing.
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