CERN Scientists Use Lasers to Cool Antimatter to Near Absolute Zero, Challenging Modern Physics Theories

Physicists from CERN's Antihydrogen Laser Physics Apparatus (ALPHA) in Canada have discovered a way to use lasers to deep-freeze anti-matter.

In a new study (Laser cooling of antihydrogen atoms), scientists suppressed thermal jitters of antihydrogen atoms, freezing the antiatoms to near absolute zero. This way of slowing down antimatter, or normal matter's counterpart that is oppositely charged, could guide scientists in creating the very first antimatter molecules. Repressing wayward antimatter using lasers may also help physicists to precisely gauge the antiatoms' properties, researchers said in the report.

Antimatter is not often encountered as normal matter, since the two destroy each other upon contact, researchers said, and as such is difficult to keep and investigate.

The technique allowed the scientists to cool the antimatter to just one-twentieth of a degree above absolute zero, which is 3,000 times colder than the coldest temperature ever recorded in Antarctica.

Antimatter Experiment Seen to Answer the Universe's Biggest Secrets

A comparison of antiatoms and normal atoms could examine and validate the universe's essential symmetries and biggest secrets, such as how gravity affects antimatter.

Scientists have chilled the atoms by decelerating their speed using a barrage of light particles or photons. Such cooling of antimatter using lasers has been difficult since making antimatter is challenging, researchers said.

To make these antihydrogen atoms, the physicists combined antiprotons with positrons, which are the antiparticles of electrons. After several hours, the laser beam that is tuned to a specific UV light frequency decelerated the antihydrogen atoms from a speed of 90 meters per second to just about 10 meters per second.

How is Antimatter Cooled?

With this technique, the scientists accelerated matter particles to near light speed, and smashed them together, creating the antiparticles. They also maneuvered and slowed the speeding antiparticles by utilizing potent magnetic and electric fields. In the end, researchers confined positron clouds and antiprotons within a magnetic field until they were combined to create antihydrogen. Researchers would then cool the antihydrogen by blasting it with a laser.

Since particle movement creates heat, cooling antimatter would need photons in the laser beam traveling in the opposite direction of the active antimatter particles. Since photons have their own momentum, hydrogen absorbs them as they travel in the opposite direction can slow down the antihydrogen. However, light needs to be tuned to a particular wavelength to interact with the antimatter.

Challenging the Idea of CPT symmetry

Upcoming observations of supercooled antihydrogen would test the idea of CPT symmetry or change-parity-time. This principle in physics asserts that normal atoms should take in and release photons with the similar energies of their antimatter counterparts. Even the smallest differences between hydrogen and antihydrogen could weaken modern physics theories.

At the same time, Einstein's theory of gravity shows that normal matter and antimatter should descend to Earth at equal rates. Experiments that had laser-cooled antiatoms dropping into a free fall offer a clearer perception of the effects of gravity.

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