  We study the quantum correlations of free scalar field with vacuum ambiguity
of de Sitter space. We show the occurrence of degradation of quantum
entanglement and quantum discord between field modes for inertial observer in
curved space due to the radiation associated with cosmological horizon. In
particular, we find that quantum correlations can be used to encode infinite de
Sitter invariant vacua, which correspond to infinite set of possible physical
worlds. This may provide a superselection rule of physical vacuum via quantum
information tasks. We also discuss the simulation of such quantum effects of
vacuum ambiguity in ion trap experiments.
