Attractive photons in a quantum nonlinear medium

Here we demonstrate a quantum nonlinear medium inside which individual photons travel as massive particles with strong mutual attraction, such that the propagation of photon pairs is dominated by a two-photon bound state. We achieve this through dispersive coupling of light to strongly interacting atoms in highly excited Rydberg states. We measure the dynamical evolution of the two-photon wave function using time-resolved quantum state tomography, and demonstrate a conditional phase shift exceeding one radian, resulting in polarization-entangled photon pairs. Particular applications of this technique include all-optical switching, deterministic photonic quantum logic and the generation of strongly correlated states of light.

Ummm, sure. How’s about we convert that into popcultureese?

Scientists create real-life Star Wars lightsaber

“It’s not an in-apt analogy to compare this to lightsabers,” said Professor Mikhail Lukin. “When these photons interact with each other, they’re pushing against and deflect each other. The physics of what’s happening in these molecules is similar to what we see in the movies.”

The translation seems to be that scientists have found a way to make photons interact with each other and actually bind together into “molecules.” I’m not entirely sure how that translates to “light saber;” my first thought was more along the lines of those damned Death Star laser beams that come together at a point in empty space and change direction.