De Sitter space with finitely many states: A toy story

Maulik Parikh, Erik Verlinde

Research output: Chapter in Book/Report/Conference proceedingChapter

2 Scopus citations


The finite entropy of de Sitter space suggests that in a theory of quantum gravity there are only finitely many states. It has been argued that in this case there is no action of the de Sitter group consistent with unitarity. In this note we propose a way out of this if we give up the requirement of having a hermitian Hamiltonian. We argue that some of the generators of the de Sitter group act in a novel way, namely by mixing in- and out-states. In this way it is possible to have a unitary S-matrix that is finite-dimensional and, moreover, de Sitter-invariant.

Original languageEnglish (US)
Title of host publicationThe Tenth Marcel Grossmann Meeting
Subtitle of host publicationOn Recent Developments in Theoretical and Experimental General Relativity, Gravitation and Relativistic Field Theories
PublisherWorld Scientific Publishing Co.
Number of pages6
ISBN (Electronic)9789812704030
ISBN (Print)9789812566676
StatePublished - Jan 1 2006
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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