2016/08/31 by Maresuke Shiraishi · 48 citations
Earth and Planetary Sciences · Physics and Astronomy · #Anisotropy #Astrophysics #Bispectrum #Black Holes and Theoretical Physics #CMB cold spot #Cosmic microwave background #Cosmology and Gravitation Theories #Geophysics and Gravity Measurements #Inflation (cosmology) #Inflaton #Mathematical physics #Non-Gaussianity #Particle physics #Physics #Quantum mechanics #Spectral density #Statistics #Theoretical physics #Trispectrum #astro-ph.CO #gr-qc #hep-ph
paper · pdf · doi:10.1103/physrevd.94.083503
published in Physical review. D/Physical review. D. 94(8) (American Physical Society) · 11 pages, 4 figures; version matching publication in PRD
openalex publication_date 2016/10/04 · arxiv created 2016/10/05 · arxiv updated 2016/10/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Under the existence of chiral non-Gaussian sources during inflation, the trispectrum of primordial curvature perturbations can break parity. We examine signatures of the induced trispectrum of the cosmic microwave background (CMB) anisotropies. It is confirmed via a harmonic-space analysis that, as a consequence of parity violation, such a CMB trispectrum has nonvanishing signal in the \ensuremathℓ1+\ensuremathℓ2+\ensuremathℓ3+\ensuremathℓ4=odd domain, which is prohibited in the concordance cosmology. When the curvature trispectrum is parametrized with Legendre polynomials, the CMB signal due to the Legendre dipolar term is enhanced at the squeezed configurations in \ensuremathℓ space, yielding a high signal-to-noise ratio. A Fisher matrix computation results in a minimum detectable size of the dipolar coefficient in a cosmic-variance-limited-level temperature survey as d1odd=640. In an inflationary model where the inflaton field couples to the gauge field via an f(\ensuremathφ)(F2+F\stackrel\texttildelowF) interaction, the curvature trispectrum contains such a parity-odd dipolar term. We find that, in this model, the CMB trispectrum yields a high signal-to-noise ratio compared with the CMB power spectrum or bispectrum. Therefore, the \ensuremathℓ1+\ensuremathℓ2+\ensuremathℓ3+\ensuremathℓ4=odd signal could be a promising observable of cosmological parity violation.