2002/04/30 by Hong Liu, Gregory Moore, Nathan Seiberg · 4 citations
Mathematics · Physics and Astronomy · #Amplitude #Big Crunch #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #De Sitter universe #Gravitational singularity #Mathematical analysis #Mathematical physics #Mathematics #Noncommutative and Quantum Gravity Theories #Orbifold #Physics #Quantum mechanics #Scattering amplitude #Singularity #String (physics) #String theory #Theoretical physics #Universe #hep-th
paper · pdf · doi:10.1088/1126-6708/2002/06/045
published as JHEP 0206:045,2002 · 27 pages, minor changes and note added
arxiv created 2002/06/07 · openalex publication_date 2002/06/21 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We consider string theory in a time dependent orbifold with a null singularity. The singularity separates a contracting universe from an expanding universe, thus constituting a big crunch followed by a big bang. We quantize the theory both in light-cone gauge and covariantly. We also compute some tree and one loop amplitudes which exhibit interesting behavior near the singularity. Our results are compatible with the possibility that strings can pass through the singularity from the contracting to the expanding universe, but they also indicate the need for further study of certain divergent scattering amplitudes.