  A polarization correlation experiment with two maximally entangled photons
created by spontaneous parametric down-conversion is studied in the Weyl-Wigner
formalism, that reproduces the quantum predictions. An interpretation is
proposed in terms of stochastic processes assuming that the quantum vacuum
fields are real. This proves that local realism is compatible with the
violation of Bell inequalities, thus rebutting the claim that local realism has
been refuted by entangled photon experiments. Entanglement appears as a
correlation between fluctuations of a signal field and vacuum fields.
