Detecting single gravitons with quantum sensing

The quantization of gravity is widely believed to result in gravitons -- particles of discrete energy that form gravitational waves. But their detection has so far been considered impossible.

In this talk, I'll discuss how signatures of single gravitons can be observed in laboratory experiments. We show that stimulated and spontaneous single-graviton processes can become relevant for massive quantum acoustic resonators and that stimulated absorption can be resolved through measurement of single phonon transitions. Our results show that single graviton signatures are within reach of realistic albeit challenging laboratory experiments. In analogy to the discovery of the photo-electric effect for photons, such signatures can provide the first experimental evidence of the quantization of gravity.