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arXiv · 2404.05289

Scalar induced gravitational waves in chiral scalar-tensor theory of gravity

Jia-Xi Feng·Fengge Zhang·Xian Gao
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Abstract

We study the scalar induced gravitational waves (SIGWs) from a chiral scalar-tensor theory of gravity. The parity-violating (PV) Lagrangian contains the Chern-Simons (CS) term and PV scalar-tensor terms, which are built of the quadratic Riemann tensor term and first-order derivatives of a scalar field. We consider SIGWs in two cases, in which the semi-analytic expression to calculate SIGWs can be obtained. Then, we calculate the fractional energy density of SIGWs with a monochromatic power spectrum for the curvature perturbation. We find that the SIGWs in chiral scalar-tensor gravity behave differently from those in GR before and after the peak frequency, which results in a large degree of circular polarization.

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Jia-Xi Feng, Fengge Zhang, Xian Gao. 2024-04-08. Scalar induced gravitational waves in chiral scalar-tensor theory of gravity. https://doi.org/10.1140/epjc%2Fs10052-024-13097-7

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