2014/05/13 by Namit Mahajan · 4 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Context (archaeology) #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Gravitational wave #Horizon #Inflation (cosmology) #Physics #Quantum #Quantum electrodynamics #Quantum entanglement #Quantum mechanics #Scalar (mathematics) #Tensor (intrinsic definition) #Theoretical physics #Tilt (camera) #Vacuum expectation value #Vacuum state #gr-qc #hep-ph #hep-th
paper · pdf · open access · doi:10.1016/j.physletb.2015.03.010
published in Physics Letters B 743, 403-407 (Elsevier BV) · 5 pages
arxiv created 2014/05/13 · openalex publication_date 2015/03/09 · arxiv updated 2015/06/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
BICEP2 result on the tensor to scalar ratio r indicates a blue tilt in the primordial gravitational wave spectrum. This blue tilt and the observed large value r=0.2 are difficult to accommodate within the single field inflationary scenarios under standard conditions. Non-Bunch–Davies vacuum states have been proposed as a possibility. Such vacua are known to lead to pathologies. In this note we point out that it is known that these states ought to be interpreted as excited/squeezed states built over the standard Bunch–Davies vacuum in order to avoid pathological issues. We discuss the associated entanglement properties due to de Sitter horizon, and how such an approach may be more natural in the context of inflation. In particular, we suggest to employ entanglement considerations in de Sitter background to study the nature and intrinsic properties of modified initial states.