In pure axion inflation, detectable gravitational wave signals arise only in parameter regions with strong backreaction that violate the upper bound on ΔN_eff.
hub Mixed citations
Primordial gravitational waves, precisely: The role of thermodynamics in the Standard Model
Mixed citation behavior. Most common role is background (55%).
abstract
In this paper, we revisit the estimation of the spectrum of primordial gravitational waves originated from inflation, particularly focusing on the effect of thermodynamics in the Standard Model of particle physics. By collecting recent results of perturbative and non-perturbative analysis of thermodynamic quantities in the Standard Model, we obtain the effective degrees of freedom including the corrections due to non-trivial interaction properties of particles in the Standard Model for a wide temperature interval. The impact of such corrections on the spectrum of primordial gravitational waves as well as the damping effect due to free-streaming particles is investigated by numerically solving the evolution equation of tensor perturbations in the expanding universe. It is shown that the reevaluation of the effects of free-streaming photons and neutrinos gives rise to some additional damping features overlooked in previous studies. We also observe that the continuous nature of the QCD crossover results in a smooth spectrum for modes that reenter the horizon at around the epoch of the QCD phase transition. Furthermore, we explicitly show that the values of the effective degrees of freedom remain smaller than the commonly used value 106.75 even at temperature much higher than the critical temperature of the electroweak crossover, and that the amplitude of primordial gravitational waves at a frequency range relevant to direct detection experiments becomes $\mathcal{O}(1)\,\%$ larger than previous estimates that do not include such corrections. This effect can be relevant to future high-sensitivity gravitational wave experiments such as ultimate DECIGO. Our results on the temperature evolution of the effective degrees of freedom are made available as tabulated data and fitting functions, which can also be used in the analysis of other cosmological relics.
hub tools
citation-role summary
citation-polarity summary
representative citing papers
Defines peak-integrated sensitivity curves (PISCs) that fold in the expected spectral shape of gravitational waves from cosmological phase transitions and supplies semianalytical fits plus public data for major detectors.
Full numerical N-body treatment is required for reliable gravitational wave predictions from nonspherical collapse in early matter-dominated eras, with resulting spectra mappable to detector sensitivities via horizon mass and reheating temperature.
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.
An improved Bogoliubov numerical method computes the full primordial GW spectrum from inflation to reheating and shows that inflaton anharmonicity imprints distinctive features at high frequencies.
Dark matter freezes in from non-thermal Z' decays before reheating ends in an inflationary model with a secluded U(1)_D gauge sector, Z' reheaton, and lattice treatment of non-perturbative effects, opening viable parameter space with GW probes.
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.
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.
Metric-affine gravity formulates equivalence principle violations via non-metricity that parallel finite-temperature mass-ratio shifts, and a generalized Fermi-Walker derivative shows no orthonormal tetrad propagates along observer worldlines.
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.
TransitionListener v2.0 supplies an end-to-end pipeline from scalar potential to gravitational wave spectra with improved handling of transition dynamics and bubble separation.
Forecasts show that adding FAST/SKA upper or lower limits on scalar-induced GWs to CMB+BAO data shifts the scalar spectral index ns by several sigma in LambdaCDM+r and extended models, offering a potential detection indicator.
Presents the science case, reference design, and project plan for the CMB-S4 ground-based CMB experiment.
A review that unifies analytical expressions for scalar-induced gravitational waves and emphasizes calculations for non-radiation-dominated cosmologies.
citing papers explorer
-
New Sensitivity Curves for Gravitational-Wave Signals from Cosmological Phase Transitions
Defines peak-integrated sensitivity curves (PISCs) that fold in the expected spectral shape of gravitational waves from cosmological phase transitions and supplies semianalytical fits plus public data for major detectors.