Search for a Gravitational-Wave Background from Sound Speed Resonance from Advanced LIGO and Advanced Virgo's First Three Observing Runs

TL;DR

This paper searches for a stochastic gravitational-wave background caused by sound speed resonance during inflation, using data from Advanced LIGO and Virgo, and sets upper limits on the model parameters.

Contribution

First search for SIGWs from sound speed resonance using LIGO and Virgo data, constraining inflationary models with nonperturbative amplification effects.

Findings

No significant detection of the SGWB signal.

Placed upper limits on the SSR model parameters.

Demonstrated current detectors' capability to probe inflation models.

Abstract

We search for a stochastic gravitational-wave background (SGWB) originating from scalar-induced gravitational waves (SIGWs) with the sound speed resonance (SSR) effect using data from Advanced LIGO and Advanced Virgo's first three observing runs. The SSR mechanism, characterized by an oscillating sound speed squared term, can induce a nonperturbative parametric amplification of specific perturbation modes during inflation, leading to enhanced primordial curvature perturbations and a significant SIGW signal. We perform a Bayesian analysis to constrain the model parameters describing the SGWB spectrum from the SSR effect. Our results show no statistically significant evidence for the presence of such a signal in the current data. Consequently, we place an upper limit of $|\tau_0| \lesssim 5.9 \times 10^3\,\mathrm{s}$ at $95\%$ confidence level on the start time of the oscillation in the SSR model. These results demonstrate the capability of current gravitational wave detectors to probe inflation models through the SSR mechanism and paves the way for future searches with improved sensitivity.