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arXiv · 2105.10642

High frequency background gravitational waves from spontaneous emission of gravitons by hydrogen and helium

Jiawei Hu·Hongwei Yu
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Abstract

A direct consequence of quantization of gravity would be the existence of gravitons. Therefore, spontaneous transition of an atom from an excited state to a lower-lying energy state accompanied with the emission of a graviton is expected. In this paper, we take the gravitons emitted by hydrogen and helium in the Universe after recombination as a possible source of high frequency background gravitational waves, and calculate the energy density spectrum. Explicit calculations show that the most prominent contribution comes from the $3d-1s$ transition of singly ionized helium $\mathrm{He}^{+}$, which gives a peak in frequency at $\sim10^{13}$ Hz. Although the corresponding energy density is too small to be detected even with state-of-the-art technology today, we believe that the spontaneous emission of $\mathrm{He}^{+}$ is a natural source of high frequency gravitational waves, since it is a direct consequence if we accept that the basic quantum principles we are already familiar with apply as well to a quantum theory of gravity.

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Jiawei Hu, Hongwei Yu. 2021-05-22. High frequency background gravitational waves from spontaneous emission of gravitons by hydrogen and helium. https://doi.org/10.1140/epjc%2Fs10052-021-09263-w

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