Werner gap in presence of simple coloured noise

Understand

A `Werner gap' is the range of relevant parameters characterising a quantum state for which it is both entangled and admits local hidden variable model.

• Werner showed that the gap becomes maximal for entanglement mixed with white noise if subsystems have infinitely many levels.
• Here we study pure entangled states mixed with simple coloured noise modelled as a single pure product state.
• We provide an explicit local hidden variable model for quantum correlations of some states of this family and give hints that likely there is a model for all quantum predictions.