  Establishing quantum entanglement between two distant parties is an essential
step of many protocols in quantum information processing. One possibility for
providing long-distance entanglement is to create an entangled composite state
within a lab and then physically send one subsystem to a distant lab. However,
is this the "cheapest" way? Here, we investigate the minimal "cost" that is
necessary for establishing a certain amount of entanglement between two distant
parties. We prove that this cost is intrinsically quantum, and is specified by
quantum correlations. Our results provide an optimal protocol for entanglement
distribution and show that quantum correlations are the essential resource for
this task.
