Site Writing Technological Innovation – 04/01/2021
Anti-hydrogen cloud being cooled by a laser.
[Imagem: Chukman So]
Comparison of matter with antimatter
The ALPHA experiment, which works alongside the LHC (Large Hdron Collider)) managed for the first time to cool anti-hydrogen tomes – the simplest form of anti-matter – using laser light.
The technique, known as laser cooling, was first demonstrated 40 years ago in normal matter and today is the basis of many fields of research.
Its first anti-matter application opens the door to considerably more accurate measurements of the internal structure of the anti-hydrogen and how it behaves under the influence of gravity – we do not know whether the anti-matter falls up or down.
And comparing these measurements with those of the common hydrogen atom can reveal differences between the matter and antimatter atoms. These differences, if they really exist, may shed light on why the Universe is composed only of matter, an imbalance known as matter-antimatter asymmetry, since both should have been created in equal quantities in the Big Bang.
“The ability to cool laser anti-hydrogen atoms is a game changer for spectroscopic and gravitational measurements and can lead to new perspectives in antimatter research, such as the creation of antimatter molecules and the development of antitome interferometry,” he said. the physical Jeffrey Hangst. “We are in the clouds. About a decade ago, laser antimatter cooling was in the realm of science fiction.”
Laser cooling of antimatter
The ALPHA team produces anti-hydrogen atoms by taking antiprotons from an Antiproton Decelerator and linking them with anti-electrons (or psitrons) created by a sodium-22 source.
Then, the resulting anti-hydrogen atoms (about 1,000 of them) are trapped in a magnetic trap, which prevents them from coming into contact with the matter and annihilating themselves.
Next, the team usually conducts spectroscopic studies, that is, measures the response of the antitoms to electromagnetic radiation – laser light or microwave. These studies have already allowed, for example, to measure the electronic transition 1S-2S in anti-hydrogen with unprecedented accuracy.
However, the accuracy of these spectroscopic measurements and other measurements, such as the behavior of anti-hydrogen in the Earth’s gravitational field, is limited by the kinetic energy or temperature of the antitomes.
to which laser cooling enters.
In this technique, the laser photons are absorbed by the atoms, causing them to reach a higher energy state. The antitomes then emit photons and spontaneously decay back to their initial state. As this interaction depends on the speed of the atoms, and as the photons give them momentum, repeating this cycle of absorption-emission many times leads to the cooling of the atoms.
[Imagem: Maximilien Brice/Julien Ordan/CERN]
Antimatria not absolute zero
In the laser cooling of the material it is already possible to bring the atoms to near absolute zero. In this first cooling of the antimatter, the antitomes were not so cold, but the reduction of the movement of the antimatter cloud by a factor of 10 shows that this is the way. Future optimizations should include increasing the density of the antitome cloud, so that the interaction with the laser is optimized.
“Historically, researchers have struggled to cool normal hydrogen by laser, so this has been seen as a crazy dream for us for many years,” said Makoto Fujiwara, the first proponent of the idea of using a pulsed laser to cool the anti- hydrogen. “Now, we can dream about even crazier things about antimatter.”
And because colder tomes take up less space, the cooling technique can help improve techniques for trapping antimatter and keeping it under control.
Bibliography:Article: Laser cooling of antihydrogen atoms
Autores: C. J. Baker, W. Bertsche, A. Capra, C. Carruth, C. L. Cesar, M. Charlton, A. Christensen, R. Collister, A. Cridland Mathad, S. Eriksson, A. Evans, N. Evetts, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, P. Grandemange, P. Granum, J. S. Hangst, W. N. Hardy, M. E. Hayden, D. Hodgkinson, E. Hunter, C. A. Isaac, M. A. Johnson, J. M. Jones, S. A. Jones, S. Jonsell, A. Khramov, P. Knapp, L. Kurchaninov, N. Madsen, D. Maxwell, J. T. K. McKenna, S. Menary, J. M. Michan, T. Momose, P. S. Mullan, J. J. Munich, K. Olchanski, A. Olin, J. Peszka, A. Powell, P. Pusa, C. . Rasmussen, F. Robicheaux, R. L. Sacramento, M. Sameed, E. Sarid, D. M. Silveira, D. M. Starko, C. So, G. Stutter, T. D. Tharp, A. Thibeault, R. I. Thompson, D. P. van der Werf, J. S. Wurtele
Vol .: 592, pages 35-42
DOI: 10.1038 / s41586-021-03289-6
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