2018/09/30 by Nicola Bartolo, Giorgio Orlando, Maresuke Shiraishi · 2 citations
Physics and Astronomy · #Bispectrum #Cosmic microwave background #Cosmology and Gravitation Theories #Curvature #Gravitational wave #Graviton #Non-Gaussianity #Noncommutative and Quantum Gravity Theories #Observable #Parity (physics) #Pulsars and Gravitational Waves Research #Scalar (mathematics) #astro-ph.CO #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/1475-7516/2019/01/050
published as JCAP01(2019)050 · 16 pages, 1 figure; version matching publication in JCAP
openalex created_date 2018/10/05 · arxiv created 2019/01/25 · openalex publication_date 2019/01/25 · arxiv updated 2019/01/28 · openalex updated_date 2026/08/05
Chern-Simons gravity coupled to the scalar sector through a generic coupling function f (ϕ) can be tested at the very high energies of the inflationary period. In ref. [1], we computed the theoretical parity breaking signatures of the ⟨ γ γ ζ⟩ primordial bispectrum which mixes two gravitons and one scalar curvature perturbation. We defined a parameter Π which measures the level of parity breaking of the corresponding bispectrum. In this work we forecast the expected 1 σ error on Π using the cosmic microwave background (CMB) angular bispectra. We find that, given the angular resolution of an experiment like Planck , Π ∼ 10 6 is detectable via the measurement of BBT or BBE angular bispectra if the tensor-to-scalar ratio r = 0.01. We also show that, from the theoretical point of view, Π can be greater than 10 6 . Thus, our conclusion is that BBT or BBE CMB angular bispectra can become an essential observable for testing Chern-Simons gravity in the primordial universe.