# phys: three forms of ambiguity in the definition of entanglement

<< A more general definition (of entanglement) was published by Thaller, (B. Thaller, Advanced Visual Quantum Mechanics, (Springer 2005) p218) "A state of a compound system is called entangled if it cannot be written as a single tensor product of subsystem states. A state in the product form is called unentangled or separable."  >>

The paper << discusses experiments with single-particle systems, some of whose states appear to be entangled. (..) Three forms of ambiguity are discussed. The choice of state-space and its dimensions is a matter of taste. There is not an a-priori natural partitioning of the state-space. The observables are not necessarily experimentally accessible and only determined by theory-laden extrapolation from experimental results. >>

Robert Shaw. Single-particle entanglement and three forms of ambiguity. arXiv:1912.11349v1 [physics.hist-ph]. Dec 22, 2019

https://arxiv.org/abs/1912.11349