Imprints of quantum gravity effects on gravitational waves: a comparative study using extreme mass-ratio inspirals

TL;DR

This study investigates how loop quantum gravity modifications to black hole spacetimes affect gravitational wave signals from extreme mass-ratio inspirals, assessing their detectability with LISA and constraining quantum parameters.

Contribution

It compares two LQG black hole models using EMRI waveforms to evaluate their quantum gravity signatures and detectability with future gravitational wave detectors.

Findings

The first LQG black hole model shows stronger EMRI signatures.

LQG effects could be detectable with LISA.

Constraints on quantum correction parameter $z$ can be derived.

Abstract

Within a generally covariant Hamiltonian framework of loop quantum gravity (LQG), two black hole models parameterized by a quantum correction $\zeta$ have recently been constructed. Using extreme mass-ratio inspirals (EMRIs) as high-precision probes, we investigate the imprints of this LQG deformation in the surrounding spacetime. Waveforms generated via an improved augmented analytic kludge (AAK) model in both LQG black hole backgrounds and in Schwarzschild spacetime are compared through a faithfulness analysis. This allows us to quantify the detectability of the deviation with LISA and to derive constraints on $\zeta$ based on a detection threshold. We find that the first LQG black hole model produces significantly stronger signatures in EMRI signals than the second, making its quantum gravity effects more accessible to future space-borne gravitational-wave detection.