Atoms at the Interface of Quantum Theory and Gravity

Atomic and optical platforms provide a powerful route to exploring the interface between quantum theory, relativity, and field theory in experimental settings. In this talk, I will present our broader research program aimed at identifying observable signatures of relativistic and gravitational effects in quantum systems and assessing their relevance for precision measurements and quantum technologies. First, I will discuss our recent results showing how gravitational waves imprint amplitude and frequency information on spontaneous emission of atoms through spectral sidebands, directional photon emission, and how they lead to collective effects (gravitational wave induced photon superradiance) in atomic arrays, even when single-atom decay rates remain unchanged. I will then turn to a complementary direction at the foundations of quantum field theory, where we propose how a quantum mirror based on a sub-wavelength atomic array can probe foundations of quantum field theory: local particle content in a subregion of an empty cavity arising from entanglement between spatial sub-regions of the electromagnetic vacuum.  Together, these results illustrate how engineered atomic systems can access regimes where quantum field theory, atom-optics, and general relativity intersect.