Tensor-induced non-Gaussianity from primordial gravitational waves generates a unique scale-dependent halo bias correction that can reach order-one amplitude for rare high-redshift halos at z=7.
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Improved Calculation of the Primordial Gravitational Wave Spectrum in the Standard Model
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abstract
We show that the energy density spectrum of the primordial gravitational waves has characteristic features due to the successive changes in the relativistic degrees of freedom during the radiation era. These changes make the evolution of radiation energy density deviate from the conventional adiabatic evolution, \rho_r~ a^{-4}, and thus cause the expansion rate of the universe to change suddenly at each transition which, in turn, modifies the spectrum of primordial gravitational waves. We take into account all the particles in the Standard Model of elementary particles. In addition, free-streaming of neutrinos damps the amplitude of gravitational waves, leaving characteristic features in the energy density spectrum. Our calculations are solely based on the standard model of cosmology and particle physics, and therefore these features must exist. Our calculations significantly improve the previous ones which ignored these effects and predicted a smooth, featureless spectrum.
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representative citing papers
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citing papers explorer
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Tracing Primordial Gravitational Waves via non-Gaussian Signatures of Halo Bias
Tensor-induced non-Gaussianity from primordial gravitational waves generates a unique scale-dependent halo bias correction that can reach order-one amplitude for rare high-redshift halos at z=7.
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Freeze-out and spectral running of primordial gravitational waves in viscous cosmology
Shear viscosity adds damping to primordial gravitational waves, producing an extra red tilt for constant viscosity-to-Hubble ratio and a k-dependent blue tilt from freeze-out in the electron-photon-baryon plasma with fractional difference of order 10^{-3}.
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Reviving Motivated Inflationary Potentials with $K$-inflation in the light of ACT
K-inflation with non-canonical kinetic term G(φ) shifts α-attractor T-models and natural inflation into the Planck-ACT-LB-BK18 allowed region while satisfying Swampland conjectures and producing testable GW spectra.
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DESI and Gravitational Wave Constraints Challenge Quintessential {\alpha}-Attractor Inflation
Alpha-attractor quintessential inflation models are disfavored by DESI observations and Delta Neff limits from gravitational waves, as they predict an inconsistent scalar spectral index when the gravitational-wave abundance is constrained.
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Gravitational Waves from Matter Perturbations of Spectator Scalar Fields
A spectator scalar field with strong portal coupling to the inflaton sources a stochastic gravitational wave background reaching Ω_GW h² ∼ 10^{-11} at frequencies 10^7-10^8 Hz for benchmark parameters σ/λ ≃ 10^4 and T_reh = 2×10^{14} GeV.
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From WIMP to FIMP during reheating: collider vs non-collider probes for p-wave annihilation
Collider experiments can strongly constrain p-wave-suppressed derivative operators and thereby limit reheating temperature, DM mass, and interaction scale needed to match observed DM abundance during reheating.
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Gravitational Waves from Post-Inflationary Magnetism: Direct and Scalar-Induced Contributions
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