  Hawking radiation can be regarded as a spontaneous and continuous creation of
virtual particle-antiparticle pairs outside the event horizon of a black hole
where strong tidal forces prevent the annihilation: the particle escapes to
infinity contributing to the Hawking flux, while its corresponding antiparticle
partner enters the event horizon and ultimately reaches the singularity. The
aim of this paper is to investigate the energy density correlations between the
Hawking particles and their partners across the event horizon of two models of
non-singular black holes by calculating the two-point correlation function of
the density operator of a massless scalar field. This analysis is motivated by
the fact that in acoustic black holes particle-partner correlations are
signalled by the presence of a peak in the equal time density-density
correlator. Performing the calculation in a Schwarzschild black hole it was
shown in [1] that the peak does not appear, mainly because of the singularity.
It is then interesting to consider what happens when the singularity is not
present. In the Hayward and Simpson-Visser non-singular black holes we show
that the density-density correlator remains finite when the partner particle
approaches the hypersurface that replaces the singularity, opening the
possibility that partner-particle correlations can propagate towards other
regions of spacetime instead of being lost in a singularity.
