Demystifying graviton detection

The detection of single gravitons has so far been considered impossible. In this talk, I will show that the absorption and detection of single gravitons can in fact be observed [1]. The result relies on quantum sensing of discrete energy transfer of only single quanta between a gravitational wave and a detector. I will present how and why graviton detection is realistic, and why it has been overlooked previously. The experimental requirements, while challenging, are realistically attainable. I will also discuss its relevance for first tests of properties of single gravitons with a historic inspiration from early tests of the quantum properties of light [2]. Even though graviton detection alone is insufficient to conclusively prove that gravity must be quantized, the results show that it can provide empirical input on linearized quantum gravity and its alternatives, in analogy to the exploration of the quantum nature of light in the early 20^th century.

[1] G. Tobar, S. K. Manikandan, T. Beitel, and I. Pikovski. "Detecting single gravitons with quantum sensing." Nature Communications 15, 7229 (2024)

[2] V. Shenderov, M. Suppiah, T. Beitel, G. Tobar, S. K. Manikandan, and I. Pikovski. "Stimulated absorption of single gravitons: First light on quantum gravity." arXiv:2407.11929 (2024)