Recurrent Nightmares?: Measurement Theory in de Sitter Space
  The idea that asymptotic de Sitter space can be described by a finite Hilbert Space implies that any quantum measurement has an irreducible innacuracy. We argue that this prevents any measurement from verifying the existence of the Poincare recurrences that occur in the mathematical formulation of quantum de Sitter (dS) space. It also implies that the mathematical quantum theory of dS space is not unique. There will be many different Hamiltonians, which give the same results, within the uncertainty in all possible measurements. 
T. Banks, W. Fischler and S. Paban