Physics Professors Approach Real-Life Lightsaber

More than 40 years after the Star Wars saga's debut, Harvard physics professor Mikhail Lukin and MIT physics professor Vladan Vuletić say that they are closer to making the film’s iconic lightsaber a reality.

Lukin, Vuletić, and their research group at the Harvard-MIT Center for Ultracold Atoms conducted an experiment, which involved firing photons through a cloud of matter cooled to a temperature near absolute zero.

The researchers found that these elementary particles of light could be manipulated into acting as if they had mass.

Because the experiment shows that mass-like interactions between photons are possible, it suggests the possibility that lightsabers–the colliding beams of light wielded by the Jedi and the Sith alike in the “Star Wars” franchise–might one day expand beyond the realm of science fiction.

“The experiment is not a completely crazy image of how you would build a light saber,” said Thibault Peyronel, an MIT Ph.D. candidate who worked on the project. “[The experiment] opens the imagination to the idea that light is not just the simple particles that we usually think about and that if we are clever enough about it we can modify its properties.”

Vuletić said that the theoretical developments necessary for the experiment only came about within the last decade.

“This type of photonic bound state has been discussed theoretically for quite a while, but until now it hadn't been observed,” said Lukin in the paper’s press release.

The researchers expect their findings will have far less fantastic, but much-more pragmatic, applications.

While modern computers store information in electronic bits representing either 0 or 1, quantum computers employ quantum bits. These can exist in a superposition of both 0 and 1, which allows for faster and more efficient computing. Based on the experiment, those quantum bits might one day make the use of photons to store this information more efficiently.

“Photons are a good candidate [for quantum bits] because they can travel fast and transfer information over long distances,” Peyronel said.

Without photon interaction, Peyronel said, there is no way to change the information stored on a quantum logic gate--the basis for quantum circuits where the output is based on a small number of quantum bits.

He added that the team’s findings might also be used to improve infrared thermometers, which  can measure fundamental constants in physics to a very high precision, as well as for thinking about new states of matter in general.