Photons, the fundamental particles of light, have special properties that make them unique. One of these is that they do not collide into each other. Physicists, however, made a breakthrough that altered this behavior, which would have potential applications in field computing. 

In a new study published in the journal Nature on July 3, researchers from the University of Chicago reported that they have discovered a new way to make photons behave more like the particles that make up matter. 

Photons, which have zero mass, normally do not interact with each other, but researchers found that they can get particles of light to interact with each other like matter does.

Lead researcher Logan Clark said that scientists use atoms as go-betweens to make photons collide with each other, but this posed some problems.

All atoms absorb or emit light at a particular energy that matches the allowed orbits of their electrons, and photons do not interact with atoms that do not have the ideal electronic orbitals.

“We were running into a problem because the photons only interact with atoms whose electronic orbitals are at very particular energies,” Clark said.

The researchers then decided to make copies of the orbitals at energies they need. Clark already developed a technique called Floquet engineering that can manipulate quantum matter by shaking it, and the right shaking can naturally produce copies of quantum states at multiple energies.

Clark and colleagues managed to shift the orbitals of an electron. They produced their desired copies by shaking the electrons with lasers of varying intensity. 

By allowing photons to interact with the shaken atoms, the researchers created the so-called Floquet polaritons. These are hybrid particles that are part-atom and part-light that feature new behaviors. 

Unlike regular photons, these particles interact with each other relatively strongly, and this sort of type of interaction is needed to make matter from light. 

The researchers acknowledged that there is still a lot to learn about polaritons, but the breakthrough may have practical uses. Low mass, photon-like particles, for instance, may have exciting applications in the field of encrypted computing and encrypted communication.

“The production of Floquet polaritons provides a promising new route to the realization of ordered states of strongly correlated photons, including crystals and topological fluids, as well as quantum information technologies such as multimode photon-by-photon switching,” the researchers wrote.