Primordial tensor bispectra in $\mu$-CMB cross-correlations

Abstract

Cross-correlations between Cosmic Microwave Background (CMB) temperature and polarization anisotropies and $\mu$-spectral distortions have been considered to measure (squeezed) primordial scalar bispectra in a range of scales inaccessible to primary CMB bispectra. In this work we address whether it is possible to constrain tensor non-Gaussianities with these cross-correlations. We find that only primordial tensor bispectra with statistical anisotropies leave distinct signatures, while isotropic tensor bispectra leave either vanishing or highly suppressed signatures. We discuss how the angular dependence of squeezed bispectra in terms of the short and long momenta determine the non-zero cross-correlations. We also discuss how these non-vanishing configurations are affected by the way in which primordial bispectra transform under parity. By employing the so-called BipoSH formalism to capture the observational effects of statistical anisotropies, we make Fisher-forecasts to assess the detection prospects from $\mu T$, $\mu E$ and $\mu B$ cross-correlations. Observing statistical anisotropies in squeezed $⟨\gamma \gamma \gamma ⟩$ and $⟨\gamma \gamma \zeta ⟩$ bispectra is going to be challenging as the imprint of tensor perturbations on $\mu$-distortions is subdominant to scalar perturbations, therefore requiring a large, independent amplification of the effect of tensor perturbations in the $\mu$-epoch. In absence of such a mechanism, statistical anisotropies in squeezed $⟨\zeta \zeta \gamma ⟩$ bispectrum are the most relevant sources of $\mu T$, $\mu E$ and $\mu B$ cross-correlations. In particular, we point out that in anisotropic inflationary models where $⟨\zeta \zeta \zeta ⟩$ leaves potentially observable signatures in $\mu T$ and $\mu E$, the detection prospects of $⟨\zeta \zeta \gamma ⟩$ from $\mu B$ are enhanced.

36 pages, 6 figures. v3: Other typos corrected. Matched published version

References in corpus (31)

• The imprints of primordial non-gaussianities on large-scale structure: scale dependent bias and abundance of virialized objects
• Primordial Non-Gaussianities from Inflation Models
• Primordial black hole dark matter from single field inflation
• Large Nongaussianity in Axion Inflation
• Enhanced Non-Gaussianity from Excited Initial States
• Primordial Gravitational Waves from Axion-Gauge Fields Dynamics
• Planck 2018 results. IX. Constraints on primordial non-Gaussianity
• Multiple field inflation
• Parity breaking signatures from a Chern-Simons coupling during inflation: the case of non-Gaussian gravitational waves
• Inflationary tensor fossils in large-scale structure
• Primordial black hole formation in inflationary $\alpha$-attractor models
• Probing the scale dependence of non-Gaussianity with spectral distortions of the cosmic microwave background
• Analytic formulae of the CMB bispectra generated from non-Gaussianity in the tensor and vector perturbations
• Parity violation in the CMB trispectrum from the scalar sector
• On the scalar consistency relation away from slow roll
• Tensor Non-Gaussianity Search: Current Status and Future Prospects
• Testing the Early Universe with Anisotropies of the Gravitational Wave Background
• Spectral distortions from the dissipation of tensor perturbations
• Evolution of CMB spectral distortion anisotropies and tests of primordial non-Gaussianity
• CMB $\mu$ distortion from primordial gravitational waves
• Can a spectator scalar field enhance inflationary tensor mode?
• Examining the consistency relations describing the three-point functions involving tensors
• Cross-correlations as a Diagnostic Tool for Primordial Gravitational Waves
• Primordial non-Gaussianity with $\mu$-type and $y$-type spectral distortions: exploiting Cosmic Microwave Background polarization and dealing with secondary sources
• Solid Consistency
• Solid Soft Theorems
• Cosmological constraints from $\mu E$ cross-correlations
• CMB $\mu T$ cross-correlations as a probe of PBH scenarios
• The Cosmic Microwave Background Bipolar Power Spectrum: Basic Formalism and Applications
• Gravitational Wave from Axion-SU(2) Gauge Fields: Effective Field Theory for Kinetically Driven Inflation
• Constraining graviton non-Gaussianity through the CMB bispectra

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• CMB spectral distortions revisited: a new take on $\mu$ distortions and primordial non-Gaussianities from FIRAS data
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• Non-Gaussianity constraints from Planck spectral distortion cross-correlations
• Spectral Distortion Anisotropy from Inflation for Primordial Black Holes
• Probing parity-odd bispectra with anisotropies of GW $V$ modes
• Self-consistent interaction of linear gravitational and electromagnetic waves in non-magnetized plasma