Damping of gravitational waves in f(R) gravity

Haiyuan Feng; Laiyuan Su; Rong-Jia Yang; Wei-Qiang Chen

doi:10.1140/epjc/s10052-025-13940-5

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2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2025) 85: 271
https://doi.org/10.1140/epjc/s10052-025-13940-5

Regular Article - Theoretical Physics

Damping of gravitational waves in f(R) gravity

Haiyuan Feng¹^a, Laiyuan Su¹, Rong-Jia Yang²^b and Wei-Qiang Chen¹^c

¹ Department of Physics, Southern University of Science and Technology, 518055, Shenzhen, Guangdong, China
² College of Physical Science and Technology, Hebei University, 071002, Baoding, China

^a fenghaiyuanphysics@gmail.com
^b yangrongjia@tsinghua.org.cn
^c chenwq@sustech.edu.cn

Received: 14 January 2025
Accepted: 15 February 2025
Published online: 11 March 2025

Abstract

We investigate the damping of gravitational waves (GW) in f(R) gravity by matter. By applying the kinetic theory, we examine the first-order approximation of the relativistic Boltzmann equation. In the flat spacetime, we derive the evolution equations for waves in f(R) gravity and demonstrate that Landau damping is absent while collision damping is present. In the Friedmann–Robertson–Walker (FRW) cosmology, we also examine the dynamical equations for the two modes. Furthermore, in the model $f (R) = R + α R^{2}$ $f(R) = R + \alpha R^2$ , we investigate the effect of the mass term on wave amplitude decay within the neutrino system. We observe that the tensor mode with $m = 1 eV$ $m = 1 \, \text {eV}$ exhibits faster decay compared to other cases, while the scalar mode with $m = 1 eV$ $m = 1 \, \text {eV}$ appears to suppress decay.

© The Author(s) 2025

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