  We address the question of regular primordial black holes with de Sitter
interior, their remnants and gravitational vacuum solitons G-lumps as heavy
dark matter candidates providing signatures for inhomogeneity of early
universe, which is severely constrained by the condition that the contribution
of these objects in the modern density does not exceed the total density of
dark matter. Primordial black holes and their remnants seem to be most elusive
among dark matter candidates. However, we reveal a nontrivial property of
compact objects with de Sitter interior to induce proton decay or decay of
neutrons in neutron stars. The point is that they can form graviatoms, binding
electrically charged particles. Their observational signatures as dark matter
candidates provide also signatures for inhomogeneity of the early universe. In
graviatoms, the cross-section of the induced proton decay is strongly enhanced,
what provides the possibility of their experimental searches. We predict proton
decay paths induced by graviatoms in the matter as an observational signature
for heavy dark matter searches at the IceCUBE experiment.
