Simulations performed by physicists at the University of Vienna provide evidence that a single photon can simultaneously excite two neighboring atoms. This phenomenon, known as `Förster resonance energy transfer` (FRET), has been observed in experiments involving multiple photons, but this is the first time it has been shown to occur with a single photon.

FRET occurs when an excited atom transfers energy to a neighboring atom through a non-radiative process. The energy transfer is mediated by a virtual photon, which is not actually emitted or absorbed. In the case of single-photon FRET, the virtual photon is exchanged between the two atoms simultaneously, allowing both atoms to be excited at the same time.

The simulations were carried out using a quantum mechanical model of two atoms interacting with a single photon. The model showed that the probability of single-photon FRET is very small, but it is still significant enough to be detected in experiments.

The researchers believe that single-photon FRET could be used to develop new technologies for quantum computing and quantum communication. For example, single-photon FRET could be used to create a quantum entanglement between two atoms, which is a key resource for quantum computing.

The study was published in the journal Physical Review Letters.