2016/05/31 by Lorenzo Bordin, Paolo Creminelli, Mehrdad Mirbabayi +1
Physics and Astronomy · #Anisotropy #Attractor #Black Holes and Theoretical Physics #Classical mechanics #Cosmology and Gravitation Theories #De Sitter space #De Sitter universe #Galaxies: Formation, Evolution, Phenomena #Geometry #Gravitation #Graviton #Inflation (cosmology) #Mathematical analysis #Mathematical physics #Physics #Quantum mechanics #Scalar (mathematics) #Tensor (intrinsic definition) #Theoretical physics #Universe #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1088/1475-7516/2016/09/041
21 pages. v2: minor changes, matches JCAP version
arxiv created 2016/09/20 · openalex publication_date 2016/09/23 · arxiv updated 2016/10/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We point out that tensor consistency relations—i.e. the behavior of primordial correlation functions in the limit a tensor mode has a small momentum—are more universal than scalar consistency relations. They hold in the presence of multiple scalar fields and as long as anisotropies are diluted exponentially fast. When de Sitter isometries are approximately respected during inflation this is guaranteed by the Higuchi bound, which forbids the existence of light particles with spin: de Sitter space can support scalar hair but no curly hair. We discuss two indirect ways to look for the violation of tensor consistency relations in observations, as a signature of models in which inflation is not a strong isotropic attractor, such as solid inflation: (a) graviton exchange contribution to the scalar four-point function; (b) quadrupolar anisotropy of the scalar power spectrum due to super-horizon tensor modes. This anisotropy has a well-defined statistics which can be distinguished from cases in which the background has a privileged direction.