Abstract

Entangled quantum systems are known to give rise to non-classical phenomena, the most shocking of which is arguably quantum nonlocality, as witnessed by Bell inequality violation. Whereas nonlocal correlations imply the existence of entanglement, the converse question is not so easy: do all entangled states lead to nonlocality? In the simplest possible scenario the answer has for a long time known to be no: there exist certain entangled states that admit a so called local hidden variable model and thus do not violate any Bell inequality.

Here, I use tools from the area of quantum steering in order to extend this in-equivalence to more complex scenarios. I will present the first examples of genuinely multipartite entangled states admitting local hidden variable models and the first example of an entangled quantum state that does not violate any Bell inequality, even if one allows for stochastic local pre-processing. Finally, I will present some open problems.