Non-Gaussianity of Tensor Induced Density Perturbations

Abstract

We investigate the non-Gaussianity of second-order matter density perturbations induced by primordial gravitational waves (GWs). These tensor-induced scalar modes arise from local fluctuations in the GWs energy density, which is quadratic in tensor perturbations. The resulting second-order density contrast follows a chi-squared distribution, naturally exhibiting significant non-Gaussianity. We compute the bispectrum of these tensor-induced scalar modes and analyze its dependence on various primordial GWs power spectra, including scale-invariant, blue-tilted, Gaussian-bump, and monochromatic sources. We find that the bispectrum shape is inherently sensitive to the underlying GWs spectrum by construction. In particular, Gaussian-bump and monochromatic sources produce a strong signal peaking in the equilateral configuration, similar to the effect of scalar-induced tensor modes. Our findings reveal a new way to probe primordial GWs via galaxy surveys and highlight a unique feature of tensor-induced density perturbations, otherwise mimicking linear ones on sub-horizon scales.

Published in Phys. Rev. D., Added clarifications in the Introduction and Conclusion; references added

References in corpus (62)

• Observation of Gravitational Waves from a Binary Black Hole Merger
• The Cosmological Constant
• Planck 2018 results. X. Constraints on inflation
• Particle Physics Models of Inflation and the Cosmological Density Perturbation
• Overview of the DESI Legacy Imaging Surveys
• The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background
• Non-Gaussianity from Inflation: Theory and Observations
• Searching for the nano-Hertz stochastic gravitational wave background with the Chinese Pulsar Timing Array Data Release I
• Gravitational Wave Experiments and Early Universe Cosmology
• Signature of Gravity Waves in Polarization of the Microwave Background
• Cosmological Backgrounds of Gravitational Waves
• A Probe of Primordial Gravity Waves and Vorticity
• The NANOGrav 15-year Data Set: Search for Signals from New Physics
• The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background
• Gravitational Wave Spectrum Induced by Primordial Scalar Perturbations
• Semianalytic Calculation of Gravitational Wave Spectrum Nonlinearly Induced from Primordial Curvature Perturbations
• European Pulsar Timing Array Limits On An Isotropic Stochastic Gravitational-Wave Background
• BICEP2 / Keck Array x: Constraints on Primordial Gravitational Waves using Planck, WMAP, and New BICEP2/Keck Observations through the 2015 Season
• Science with the space-based interferometer LISA. IV: Probing inflation with gravitational waves
• Relativistic second-order perturbations of the Einstein-de Sitter Universe
• Science with the Einstein Telescope: a comparison of different designs
• A Cosmological Signature of the SM Higgs Instability: Gravitational Waves
• The Quest for B Modes from Inflationary Gravitational Waves
• Large Nongaussianity in Axion Inflation
• Cosmology with Phase 1 of the Square Kilometre Array; Red Book 2018: Technical specifications and performance forecasts
• The Astrophysics of Nanohertz Gravitational Waves
• Improved Calculation of the Primordial Gravitational Wave Spectrum in the Standard Model
• Parity violation in the Cosmic Microwave Background from a pseudoscalar inflaton
• Gravitational waves from resolvable massive black hole binary systems and observations with Pulsar Timing Arrays
• CMB-S4: Forecasting Constraints on Primordial Gravitational Waves
• Gravitational waves at interferometer scales and primordial black holes in axion inflation
• Relating gravitational wave constraints from primordial nucleosynthesis, pulsar timing, laser interferometers, and the CMB: implications for the early universe
• Primordial non-Gaussianity and Bispectrum Measurements in the Cosmic Microwave Background and Large-Scale Structure
• Scale-dependent gravitational waves from a rolling axion
• Gravitational Wave Production right after a Primordial Black Hole Evaporation
• Primordial Gravitational Waves from Axion-Gauge Fields Dynamics
• The gravitational-wave background null hypothesis: Characterizing noise in millisecond pulsar arrival times with the Parkes Pulsar Timing Array
• Improved reconstruction of a stochastic gravitational wave background with LISA
• Gravitational Waves Induced by Scalar Perturbations during a Gradual Transition from an Early Matter Era to the Radiation Era
• Finding the chiral gravitational wave background of an axion-SU(2) inflationary model using CMB observations and laser interferometers
• Anisotropies and non-Gaussianity of the Cosmological Gravitational Wave Background
• Clustering Fossils from the Early Universe
• Axion Inflation with an SU(2) Gauge Field: Detectable Chiral Gravity Waves
• Probing Anisotropies of the Stochastic Gravitational Wave Background with LISA
• Tests for primordial non-Gaussianity
• Large-Scale Structure with Gravitational Waves II: Shear
• Characterizing the Cosmological Gravitational Wave Background Anisotropies and non-Gaussianity
• Measuring the spectrum of primordial gravitational waves with CMB, PTA and Laser Interferometers
• Post-Newtonian Cosmological Dynamics in Lagrangian coordinates
• Primordial gravitational waves in supersolid inflation
• Inflationary tensor fossils in large-scale structure
• Primordial gravity wave fossils and their use in testing inflation
• Bending of Light by Gravity Waves
• Sound speed resonance of the stochastic gravitational wave background
• Large-Scale Structure with Gravitational Waves I: Galaxy Clustering
• Production and Backreaction of Spin-2 Particles of $SU(2)$ Gauge Field during Inflation
• The Maximal Amount of Gravitational Waves in the Curvaton Scenario
• Anisotropic tensor power spectrum at interferometer scales induced by tensor squeezed non-Gaussianity
• Seeking Inflation Fossils in the Cosmic Microwave Background
• The Impact of Observing Strategy on Cosmological Constraints with LSST
• Probing the Early History of Cosmic Reionization by Future Cosmic Microwave Background Experiments
• An Analytical Study of the Primordial Gravitational-Wave-Induced Contribution to the Large-Scale Structure of the Universe