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arXiv · 2106.05552

Universal $10^{20}$Hz stochastic gravitational waves from photon spheres of black holes

Kaishu Saito·Jiro Soda·Hirotaka Yoshino
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Abstract

We show that photon spheres of supermassive black holes generate high-frequency stochastic gravitational waves through the photon-graviton conversion. Remarkably, the frequency is universally determined as $m_e\sqrt{m_e /m_p} \simeq 10^{20} \text{Hz}$ in terms of the proton mass $m_p$ and the electron mass $m_e$. It turns out that the density parameter of the stochastic gravitational waves $ \Omega_{ \text{gw}}$ could be $ 10^{-12}$. Since the existence of the gravitational waves from photon spheres is robust, it is worth seeking methods of detecting high-frequency gravitational waves around $10^{20}$Hz.

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Kaishu Saito, Jiro Soda, Hirotaka Yoshino. 2021-06-10. Universal $10^{20}$Hz stochastic gravitational waves from photon spheres of black holes. https://doi.org/10.1103/physrevd.104.063040

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