Cost of exactly simulating quantum entanglement with classical communication

We investigate the amount of communication that must augment classical loca l hidden variable models in order to simulate the behavior of entangled qua ntum systems. We consider the scenario where a bipartite measurement is giv en from a set of possibilities and the goal is to obtain exactly the same c orrelations that arise when the actual quantum system is measured. We show that, in the case of a single pair of qubits in a Bell state, a constant nu mber of bits of communication is always sufficient-regardless of the number of measurements under consideration. We also show that, in the case of a s ystem of a Bell states, a constant times 2(n) bits of communication is nece ssary.