Entanglement Zoo I: Foundational and Structural Aspects
This work addresses foundational aspects of quantum entanglement for researchers in quantum information, but it appears incremental as it builds on existing schemes without claiming broad new applications.
The authors tackled the problem of classifying entanglement in systems violating Bell's inequalities by introducing a new entanglement scheme compatible with quantum theory, enabling modeling in complex Hilbert space for both customary and nonlocal scenarios, with detailed quantum models provided.
We put forward a general classification for a structural description of the entanglement present in compound entities experimentally violating Bell's inequalities, making use of a new entanglement scheme that we developed recently. Our scheme, although different from the traditional one, is completely compatible with standard quantum theory, and enables quantum modeling in complex Hilbert space for different types of situations. Namely, situations where entangled states and product measurements appear ('customary quantum modeling'), and situations where states and measurements and evolutions between measurements are entangled ('nonlocal box modeling', 'nonlocal non-marginal box modeling'). The role played by Tsirelson's bound and marginal distribution law is emphasized. Specific quantum models are worked out in detail in complex Hilbert space within this new entanglement scheme.