2016/10/31 by Tommi Markkanen
Physics and Astronomy · #Back-reaction #Black Holes and Theoretical Physics #Cosmological constant #Cosmological perturbation theory #Cosmology #Cosmology and Gravitation Theories #De Sitter space #De Sitter universe #Horizon #Quantum Electrodynamics and Casimir Effect #Quantum decoherence #Quantum field theory in curved spacetime #Scalar (mathematics) #Scalar field #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1088/1475-7516/2017/09/022
11 pages, 2 figures. v2: expanded text, new title and abstract. Results unchanged. v3: version accepted for publication by JCAP, added references
openalex created_date 2017/08/31 · arxiv created 2017/09/08 · openalex publication_date 2017/09/14 · arxiv updated 2017/09/20 · openalex updated_date 2026/08/05
We investigate back reaction in de Sitter space in an approach where only states that are observationally accessible are included in the density matrix. Using the Bunch-Davies vacuum as the initial condition we find for a conformal scalar field and a cosmological constant that tracing over the unobservable states beyond the cosmological horizon leads to a thermal spectrum of particles and that such a configuration is unstable under semi-classical back reaction. It is concluded that this prescription results in an instability of de Sitter space with a gradually increasing horizon size.