Back(reaction) to the future in the Unruh-De Sitter state (Q2292540)

This paper studies a scalar field in de Sitter space in two dimensions and computes the analogue of the Unruh effect. It extrapolates the results to four dimensions and argues that de Sitter space is unstable and evaporates in a timescale given by the gravitational entropy and, as in the black hole case, it ends up in a singular geometry beyond the reach of the semiclassical approximation.