The first search for scalar-induced gravitational waves via pulsar parameter drifts yields f_PBH < 10^{-10} (95% CL) for PBH masses 0.3 to 4e4 solar masses, strongly disfavoring a primordial black hole origin for LVK binary black holes.
hub Canonical reference
Scalar induced gravitational waves review
Canonical reference. 80% of citing Pith papers cite this work as background.
34
Pith papers citing it
Background
80% of classified citations
abstract
We provide a review on the state-of-the-art of gravitational waves induced by primordial fluctuations, so-called induced gravitational waves. We present the intuitive physics behind induced gravitational waves and we revisit and unify the general analytical formulation. We then present general formulas in a compact form, ready to be applied. This review places emphasis on the open possibility that the primordial universe experienced a different expansion history than the often assumed radiation dominated cosmology. We hope that anyone interested in the topic will become aware of current advances in the cosmology of induced gravitational waves, as well as becoming familiar with the calculations behind.
hub tools
citation-role summary
background 13
method 1
other 1
citation-polarity summary
representative citing papers
Hubble-flow models of ultra-slow-roll inflation introduce spurious UV artefacts in the potential that Fourier filtering removes, restoring Wands duality.
Accounting for the minimal mass spread of primordial black holes from gravitational collapse suppresses the Poltergeist GW background to the level of generic scalar-induced signals and reopens ultra-light PBH parameter space.
For infinitely differentiable effective potentials describing the post-inflation transition, the regularized power spectrum of primary gravitational waves exhibits exponential suppression at small scales.
Dissipation of small-scale primordial perturbations after neutrino decoupling cools relic neutrinos and reduces their abundance, enabling PTOLEMY to constrain the primordial curvature power spectrum to O(0.1) on scales k ≲ 3×10^5 Mpc^{-1}.
The conventional truncation in stochastic inflation is inconsistent because quadratic-noise contributions are the same perturbative order as the deterministic non-Markovian corrections.
A quenched-disorder approach with Schwinger-Keldysh path integrals produces an averaged density matrix for gravitational waves that separates phase-suppressing exponential terms from oscillatory corrections to coherent propagation.
The work shows that free-streaming dark radiation isocurvature produces a qualitatively different gravitational wave spectrum than cold dark matter isocurvature and derives constraints on isocurvature power spectra around 10^6 Mpc^{-1} from NANOGrav data.
Lattice simulations directly calculate SIGW spectra with non-Gaussianity to all orders and show that modest non-Gaussianity alters ultraviolet spectral behavior.
In pure axion inflation, detectable gravitational wave signals arise only in parameter regions with strong backreaction that violate the upper bound on ΔN_eff.
Periodic warm inflation imprints one log-periodic feature on the curvature spectrum that saturates asteroid-mass PBHs, generates dual-band GW backgrounds, and offsets the bispectrum phase by a quarter cycle fixed by spectral running.
Curvaton self-interactions in non-quadratic potentials produce a local non-Gaussian map that enables supermassive primordial black hole formation at peak amplitudes of order 10^{-5} while remaining consistent with μ-distortion bounds.
Incorporating the general-relativity mass tail df_PBH/d ln M ∝ M^3.78 smooths PBH evaporation, suppresses the scalar-induced GW signal by orders of magnitude, and reopens the ultra-light PBH window for the hot Big Bang.
Domain wall annihilation imprints a two-peaked spectrum on induced gravitational waves via an early matter-dominated phase and entropy dilution.
A phenomenological dipole anisotropy in primordial perturbations induces dipolar and quadrupolar anisotropies in SIGW energy density spectra, producing frequency-dependent PTA overlap reduction functions that depend on pulsar sky distribution, but NANOGrav 15-year data yields no significant evidence
Derives stochastic equations from Schwinger-Keldysh formalism that include quantum diffusion and classical metric perturbations for non-perturbative ultra-slow-roll inflation, validated on Starobinsky and critical Higgs models.
Multi-phase inflation with chiral vector interactions generates amplified primordial magnetic fields that induce a detectable circularly polarized gravitational-wave background.
Induced gravitational waves during inflation obey a universal tensor spectral index formula that yields near scale-invariance for slow-roll expansion regardless of the source field's original spectrum.
Extends diagrammatic approach for scalar-induced gravitational waves to arbitrary-order local PNG, deriving semi-analytic spectra for energy density, anisotropies, bispectrum and trispectrum up to quartic terms.
Covariant analysis of curvature perturbations from first-order phase transitions reveals gauge-dependent overestimation of primordial black holes and gravitational waves in prior non-covariant calculations, leading to strong suppression of both signals.
Hybrid inflation produces enhanced curvature perturbations with a broad power spectrum peak featuring k^3 infrared growth and positive f_NL fixed by tachyonic waterfall geometry, potentially accounting for PBH dark matter and LISA-detectable SGWB.
Classical part of 1-loop tensor power spectrum in de Sitter is IR divergent but cancels with vacuum part, enabling non-perturbative renormalization to extract unaffected physical information.
A transient parity-violating phase during inflation generates a robust blue-tilted (n_T ≃ 2) primordial gravitational wave spectrum at small scales with nearly maximal helicity coherence and linear polarization, offering a cosmological template for PTA data distinct from astrophysical sources.
Purely quadratic non-Gaussianity from tachyonic instability allows narrow curvature spectra to exponentially suppress primordial black hole overproduction via correlation coefficient ρ approaching -1 while retaining sizable scalar-induced gravitational waves.
citing papers explorer
-
Constraints on the Primordial Black Hole Abundance using Pulsar Parameter Drifts
The first search for scalar-induced gravitational waves via pulsar parameter drifts yields f_PBH < 10^{-10} (95% CL) for PBH masses 0.3 to 4e4 solar masses, strongly disfavoring a primordial black hole origin for LVK binary black holes.