Quantum gravity unchained: Atomic sensors as exotic field telescopes in multi-messenger astronomy

Abstract: We propose a novel, exotic physics, modality in multi-messenger astronomy. We are interested in a DIRECT detection of exotic fields emitted by the mergers. This approach must be contrasted with the INDIRECT detection strategies, e.g., based on minute exotic-physics induced changes in gravitational wave spectral features. While our strategy seems to be overly optimistic, the numbers do work out. The numbers work out because of (i) the exquisite sensitivity of atomic quantum sensors and because of (ii) the enormous amounts of energy released in the mergers. Bursts of exotic fields may, for example, be produced during the coalescence of black hole singularities, releasing quantum gravity messengers per the title of this contribution. To be detectable by the precision atomic sensors, such fields must be ultralight and ultra-relativistic and we refer to them as exotic low-mass fields (ELFs). Since the fields are massive, the group velocity of ELF bursts is smaller than the speed of light. Thereby the ELF bursts lag behind the gravitational waves. Then LIGO or other gravitational wave observatories would provide a trigger for networks of precision atomic sensors that can listen for the feeble ELF signals. We characterize ELF signatures in the sensors. ELFs would imprint a characteristic anti-chirp signal across the sensor network. This contribution to Moriond-Gravity proceedings summarizes salient points of our previous publication [Dailey et al., Nature Astronomy 5, 150 (2021)]. I aim at a discussion that is informal and accessible yet grounded in quantitative estimates.