  Arguments are provided for the reality of the quantum vacuum fields. 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 a violation
of Bell inequalities, thus rebutting the claim that it has been refuted by
experiments. Entanglement appears as a correlation between fluctuations of a
signal field and vacuum fields.
  Key words; local realism, Bell inequalities, entangled photons, Weyl-Wigner,
loopholes,vacuum fields
