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Updated: May 27, 2025

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Measuring the evolution of entanglement in Compton scattering
Igor Tkachev1, Sultan Musin2,3, Dzhonrid Abdurashitov2
1Institute for Nuclear Research RAS, Moscow, 117312, Russia. tkachev@inr.ru.
Abstract:
The evolution of the entanglement measure during Compton scattering is studied. Our analytical results show that the corresponding measure coincides with the concurrence of the two-qubit state arising after scattering. The state never collapses to a separable one, contrary to what was previously assumed. The behavior of quantum entanglement during scattering is identical to the behavior of initially classically correlated photons up to a constant factor equal to two. This is consistent with local quantum field theory, and "spooky action at a distance" is not required to explain the change in state of nonlocally entangled qubits during the measurement of one of them. Our dedicated experiment with annihilation photons confirms these results and explains the "Puzzle of Decoherence" observed recently.
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