Arrows of time and the beginning of the universe

  title={Arrows of time and the beginning of the universe},
  author={Alexander Vilenkin},
  journal={Physical Review D},
  • A. Vilenkin
  • Published 16 May 2013
  • Mathematics
  • Physical Review D
I examine two cosmological scenarios in which the thermodynamic arrow of time points in opposite directions in the asymptotic past and future. The first scenario, suggested by Aguirre and Gratton, assumes that the two asymptotic regions are separated by a de Sitter-like bounce, with low-entropy boundary conditions imposed at the bounce. Such boundary conditions naturally arise from quantum cosmology with Hartle-Hawking wave function of the universe. The bounce hypersurface breaks de Sitter… 

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