Broadcast copies reveal the quantumness of correlations

Understand

We study the quantumness of bipartite correlations by proposing a quantity that combines a measure of total correlations -- mutual information -- with the notion of broadcast copies -- i.e., generally nonfactorized copies -- of bipartite states.

• By analyzing how our quantity increases with the number of broadcast copies, we are able to classify classical, separable, and entangled states.
• This motivates the definition of the broadcast regularization of mutual information, the asymptotic minimal mutual information per broadcast copy, which we show to have many properties of an entanglement measure.