Italian researchers succeed in interfering with antimatter
– News of May 21, 2019 –
In 1923, the French physicist Louis de Broglie published a surprising article. He formulates the hypothesis that matter has an associated wave. Over the next few years, this was confirmed when researchers succeeded in interfering with electrons, protons and even whole molecules. This is proof that matter can have an undulatory behavior, like light. The wave-particle duality is today one of the key principles of quantum mechanics. Almost a century later, we wonder if antimatter is also subject to this wave-corpuscle duality.
What is antimatter ?
The antimatter is composed of particles very similar to the matter, but it has an opposite electric charge. When a particle encounters its antiparticle, they annihilate themselves in a violent flash of energy. This makes antimatter very difficult to produce and observe. It also generates many questions at the cosmos scale. The standard model of particle physics shows a strict symmetry between matter and antimatter. In other words, we should observe as much matter as antimatter, but that is not what we observe. The universe is composed of classical matter, which makes our existence possible. But for theoretical physicists, this generates many questions.
Several hypothesis are studied to explain this absence of antimatter. Maybe the universe is globally balanced between the two types of matter, but locally there would be imbalances. This implies that we live in a bubble of classical matter and that antimatter is located elsewhere. We can also imagine that there is a very small asymmetry between the properties of matter and the properties of antimatter. This asymmetry would explain why classical matter has finally triumphed in the universe.
Study shows antimatter also has an ondulatory behavior
To explore this hypothesis, we can try to study antimatter in a laboratory. For some decades, we know better and better how to produce and manipulate it and according to an article published on May 3, 2019, we know now also how to interfere with antimatter. Thanks to an interferometer specially designed for this study, an Italian team has succeeded in highlighting the wave properties of positrons, the antiparticles associated with electrons. On this side, the symmetry is respected. The system put in place by researchers, however, opens the way for perhaps more interesting tests.
Antimatter interferometry could be used to measure the acceleration of antiparticles in a gravitational field, which could explore many issues. Does antimatter fall in the same way as matter ? Are the gravitational fields of a mass of matter and the same mass of antimatter identical ? Trying to answer these questions will be very difficult because the gravitational interaction is small at the scale of a positron, but perhaps a small difference in the measurement will finally make it possible to understand where is the antimatter of the universe.
Image by NASA Mashall Space Flight Center