Year: 2026
Type: article
Abstract: We map the observational predictions of cosmological stasis in the inflationary gravitational wave background onto the sensitivity bands of current and planned gravitational wave detectors. Using the closed-form piecewise spectral template derived in the companion paper, we generate detectability maps for four stasis scenarios: canonical, dynamical scalar, vacuum-energy/matter, and vacuum-energy/radiation across the frequency bands probed by NANOGrav, SKA, LISA, DECIGO, BBO, the Einstein Telescope, and Cosmic Explorer. For scenarios in which the spectrum is suppressed, $w_s < 1/3$, the stasis feature is detectable by BBO in the region of $(w_s,ΔN)$ parameter space in which $w_s\gtrsim 0.2$ for tensor-to-scalar ratios close to the Planck upper limit, r = 0.036. For scenarios in which the spectrum is enhanced, $w_s > 1/3$, the stasis feature is detectable by BBO across the entire $(w_s,ΔN)$ parameter space for tensor-to-scalar ratios of $O(0.01)$. We characterize the Standard Model (SM) $g_*$ fine structure of the IGWB, showing that SM phase transitions introduce spectral steps of $\approx 20\%$ (electroweak, at $\sim 2.6\times10^{-6}$~Hz) and $\approx 53\%$ (QCD, at $\sim 3.6\times 10^{-9}$~Hz). For stasis scenarios with end-of-stasis temperatures below the QCD scale these steps fall inside the stasis band and constitute additional spectral features that complement the primary signature. Finally, we model the finite-width end-of-stasis transition phenomenologically, demonstrating that the spectral break at $f_{end}$ is smoothed over a log-frequency window $ΔN_\mathrm{trans}\times 3(1+w_s)/4$, and that the consistency relation $C^2=C^2(α)$ remains testable provided $ΔN_\mathrm{stasis}\gg ΔN_\mathrm{trans}$, a condition easily satisfied for all scenarios of phenomenological interest.
DOI: 10.1103/c5l9-q1vk
Authors: Gabriela Barenboim, Anne-Katherine Burns
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G103507813, G1105844351, G1272900390, G1764267590, G2917513873, Hunting Invisibles: Dark sectors, Dark matter and Neutrinos, G3098500317, G3780874795, G4087634877, G4212894969, G491712853, G5020660627, G5195188938, G5371910319, G5635532810, G633297219, G7052861868, G714608666, G776579233, G7805626310, G7863371703, G8235390948, G8497050386
OpenAlex ID: W7170090171