Scientists Cool Antimatter Close to Absolute Zero for First Time

A research team used a new laser built in Canada to manipulate antimatter atoms for the first time, a breakthrough that could lead to new discoveries in physics.

An artistic illustration of the movement of an antihydrogen atom in the ALPHA magnetic trap, before (grey) and after (blue) laser cooling. The images show various lengths of the antihydrogen’s track. (Credit: Chukman So/TRIUMF)

(CN) — Researchers have made history by manipulating antimatter with a laser, they announced in a study published Wednesday.

The European Organization for Nuclear Research-based ALPHA collaboration used a new laser developed in Canada to cool down antihydrogen to near absolute zero, according to the researchers’ article in the journal Nature.

“It was a bit of crazy dream to manipulate antimatter with laser,” said Makoto Fujiwara, ALPHA-Canada spokesperson, TRIUMF scientist, and the original proponent of the laser cooling idea. “I am thrilled that our dream has finally come true as a result of tremendous teamwork of both Canadian and international scientists.”

The team explained in its press release announcing the study that “antimatter is the otherworldly counterpart to matter.” These antiatoms have almost the exact same characteristics and behaviors as matter atoms but with the opposite charge.

For example, atoms contain electrons which have a negative electrical charge. Antimatter atoms contain positrons, which behave the same way as electrons but have a positive electrical charge.

Antimatter and matter atoms annihilate upon contact, creating a flash of energy, which makes antimatter difficult to create and work with.

According to the press release, scientists have been using lasers to manipulate regular atoms for 40 years, leading to several important discoveries in physics. Slowing down atoms through cooling allows for easier and more precise measurements.

In the article, the group described using its newly developed laser to cool magnetically trapped antihydrogen atoms in three dimensions. Laser cooling uses photons, or the quantum excitation of the magnetic field, which although have no mass still carry momentum. This laser energy can be used to exert force on another object, in this case the antihydrogen.

During the experiment the ALPHA team held and exposed antihydrogen to the laser for up to 17 hours, cooling it to almost absolute zero, which is the lowest temperature that is theoretically possible — estimated to be about -459 degrees Fahrenheit.

The breakthrough is a big win for physics and “will significantly alter the landscape of antimatter research and advance the next generation of experiments,” the release said.

“Laser-cooled antihydrogen will be a transformative tool in antimatter studies, with its most exciting applications probably yet to be dreamt of,” the journal article states. “At a minimum, it will be the starting point of our future precision measurements using magnetically trapped antihydrogen.”

Immediate applications using cooled antimatter include further study in spectroscopy — how atoms interact with electromagnetic radiation — and the Lamb shift, a difference in energy between two excited states of hydrogen atoms.

It could also be possible to create antimatter molecules by joining cooled antiatoms together, and cooling both hydrogen and antihydrogen could allow direct comparisons between the two, the paper detailed.

Very cold antimatter can also be confined in a smaller volume, allowing for a wider range of experiments, according to the researchers. New plans are already underway to release cooled antihydrogen into free space to make new quantum measurements.

Fujiwara and Takamasa Momose, a University of British Columbia researcher with ALPHA’s Canadian team who led the development of the laser, will lead a new project to further develop techniques using cooled antimatter for study.

“With this technique, we can address long-standing mysteries like: ‘How does antimatter respond to gravity? Can antimatter help us understand symmetries in physics?’” Momose said. “These answers may fundamentally alter our understanding of our universe.”

%d bloggers like this: