For the first time it has been possible to cool down antimatter. This enables an exact comparison with the matter
Scientists working on ALPHA experimentst on CERN work, it was possible for the first time to cool antimatter with a laser. The achievement opens the way to a better understanding of the internal structure of antihydrogen and the study of how it behaves under the influence of gravity.
Antihydrogen is the simplest form of atomic antimatter. Now that we have the ability to cool them, scientists will be able to make comparisons between anti-hydrogen atoms and Hydrogen atoms on, whereby we can learn the differences between antimatter and matter atoms. By finding these possible differences, we can better understand why this is Universe consists of matter
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This is a complete game changer for spectroscopic and Gravitational studies and could even shed light on antimatter research, such as B. the generation of antimatter molecules and the development of anti-atomic interferometry, says ALPHA experiment spokesman Jeffrey Hangst. A decade ago, laser cooling of antimatter belonged to the realm of science fiction.
In the ALPHA experiment, anti-hydrogen atoms are generated by antiprotons obtained in the antiproton retarder. They will with Positrons combined, the source of which is sodium-22. Normally, the anti-hydrogen atoms obtained in this way are locked in a magnetic trap that prevents their contact with matter and their destruction. In this case, spectroscopic investigations are usually carried out, in which the reaction of anti-atoms to the influence of an electromagnetic wave - laser light or microwave - is measured. However, the accuracy of such measurements is limited by the kinetic energy or temperature of the antiatoms.
This is where the need for cooling comes into play. With the technology of the Laser cooling atoms are illuminated by a laser with a photon energy that is slightly less than the energy of the transitions between the energy levels for a specific element. The photons are absorbed by the atoms, which thereby reach a higher energy level. And they occur due to the fact that the Photons Energy deficit needed to make the transition between levels out of their own kinetic energy. The atoms then emit photons with an energy that corresponds exactly to the energy difference between the atomic levels and spontaneously return to their original state. Since the energy of the emitted photon is slightly higher than the energy of the absorbed photon, the repeated absorption-emission cycle leads to the cooling of the atom.
In the most recent experiments, the ALPHA scientists cooled a cloud of Anti-hydrogen atoms with a laser for several hours. After this time, they found that the average kinetic energy of atoms decreased by more than ten times. Many of the atoms reached energies below a microelectron volt, which corresponds to a temperature of about 0,012 Kelvin. The anti-hydrogen was then subjected to spectroscopic examinations and it was found that the cooling caused a Spectral line which was almost 4 times narrower than in the examinations without laser cooling.
For many years scientists had problems with laser cooling hydrogen, so the mere thought of cooling the antihydrogen was insane. Now we can witness even more madness Antimatter dream, says Makoto Fujiwara, who suggested the above experiment.