Experimental Proof of Quantum Nonlocality without Squeezing
J. Niset, A. Acin, U. L. Andersen, N. J. Cerf, R. García-Patrón, M. Navascues, M. Sabuncu
Abstract
It is shown that the ensemble
{p(α),|α>|
α
∗
>}
where
p(α)
is a Gaussian distribution of finite variance and
|α>
is a coherent state can be better discriminated with an entangled measurement than with any local strategy supplemented by classical communication. Although this ensemble consists of products of quasi-classical states, it exhibits some quantum nonlocality. This remarkable effect is demonstrated experimentally by implementing the optimal local strategy together with a joint nonlocal strategy that yields a higher fidelity.