Electrostatic nature of cavity-mediated interactions between low-energy matter excitations

Here, the authors demonstrate that cavity quantum electrodynamical effects induce electrostatic interactions between low-energy matter excitations when these are off-resonantly coupled either directly to the cavity field or indirectly via resonant mediator modes. These findings expose the limitations of previous models that have used just one cavity mode in the electromagnetic description of the cavity. The results provide critical insights for designing nanophotonic structures leading to significant cavity-induced interactions, which could open new avenues for modifying material properties using vacuum fields.