Bell state measurement locally explained

Abstract

Abstract Entangled quantum systems can connect to the environment by means of a Bell state measurement. This is true for instance for teleportation and entanglement swapping. While the results are well understood it is not quite clear if they involve nonlocal action or if they are determined in advance. Models based on the fact that the partners of an entangled pair have the same value of a statistical parameter do not apply here. Therefore, in this work a model is presented which reproduces the quantum mechanical predictions for expectation values with spin measurements, but is not based on shared statistical parameters. The coupling of the entangled particles is instead based on the conservation of the spin angular momentum. The model refutes Bell's theorem and explains teleportation and entanglement swapping in a local manner as well. Multilevel entanglements can also be explained locally by the model. The manuscript is thus a step forward towards a complete theory describing quantum physical reality as thought possible by Einstein, Podolsky and Rosen.