2015/04/09 by Jean-Luc Lehners
Mathematics · Physics and Astronomy · #Big Crunch #Black Holes and Theoretical Physics #Classical mechanics #Cosmology and Gravitation Theories #De Sitter universe #Ekpyrotic universe #Instanton #Mathematical analysis #Mathematical physics #Mathematics #Noncommutative and Quantum Gravity Theories #Physics #Quantum #Quantum cosmology #Quantum gravity #Quantum mechanics #Singularity #Steady State theory #Theoretical physics #Universe #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1016/j.physletb.2015.09.032
6 pages, 9 figures
arxiv created 2015/04/09 · openalex publication_date 2015/09/16 · arxiv updated 2015/09/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Ekpyrotic instantons describe the emergence of classical contracting universes out of the no-boundary quantum state. However, up to now these instantons ended in a big crunch singularity. We remedy this by adding a higher-derivative term, allowing a ghost condensate to form. This causes a smooth, non-singular bounce from the contracting phase into an expanding, kinetic-dominated phase. Remarkably, and although there is a non-trivial evolution during the bounce, the wavefunction of the universe is “classical” in a WKB sense just as much after the bounce as before. These new non-singular instantons can thus form the basis for a fully non-singular and calculable ekpyrotic history of the universe, from creation until now.