Memory in de Sitter space and BMS-like supertranslations
  It is well known that the memory effect in flat spacetime is parametrized by
the BMS supertranslation. We investigate the relation between the memory effect
and diffeomorphism in de Sitter spacetime. We find that gravitational memory is
parametrized by a BMS-like supertranslation in the static patch of de Sitter
spacetime. We also show a diffeomorphism that corresponds to gravitational
memory in the Poincare/cosmological patch. Our method does not need to assume
the separation between the source and the detector to be small compared with
the Hubble radius, and can potentially be applicable to other FLRW universes,
as well as "ordinary memory" mediated by massive messenger particles.
