Constraints on ultra-slow-roll inflation from the third LIGO-Virgo observing run

TL;DR

This paper uses LIGO-Virgo data to constrain ultra-slow-roll inflation models by searching for associated gravitational wave backgrounds, providing bounds on model parameters and forecasting future experimental sensitivities.

Contribution

First constraints on USR inflation from gravitational wave data, and forecasts for future detectors to improve these bounds.

Findings

USR phase e-foldings constrained to ΔN ≲ 2.9

Power spectrum of curvature perturbations constrained to log10 P_Rp < -1.7

Future experiments can probe P_Rp down to 10^{-5.5}

Abstract

The nonattractor evolution in ultra-slow-roll (USR) inflation results in the amplification of superhorizon curvature perturbations and then induces a strong and detectable stochastic gravitational wave background. In this letter, we search for such a stochastic gravitational wave background in data from the third LIGO-Virgo observing run and place constraints on the USR inflationary models. The $e$-folding number of the USR phase are constrained to be $\Delta N \lesssim 2.9$ at the 95% confidence level and the power spectrum of curvature perturbations amplified during the USR phase is constrained to be $\log_{10}P_{R\mathrm{p}}<-1.7$ at the scales $2.9\times10^5 ~\mathrm{pc^{-1}} \lesssim k \lesssim 1.7\times10^{11}~\mathrm{pc^{-1}}$. Besides, we forecast the ability of future experiments to constrain USR inflation, and find $P_{R\mathrm{p}}\lesssim 10^{-3.6}$ for LISA and Taiji, $P_{R\mathrm{p}}\lesssim 10^{-3.3}$ for Cosmic Explore and Einstein Telescope, $P_{R\mathrm{p}}\lesssim 10^{-5.5}$ for DECIGO and Big Bang Observer and $P_{R\mathrm{p}}\lesssim 10^{-5.2}$ for Square Kilometre Array.