Antimatter particles make waves in the physics community after double-slit study

One of the oddest, most fascinating questions in the field of quantum mechanics is the dual nature of subatomic particles, which also act like waves. The time-honoured test of the wave nature of matter — the double-slit experiment — was used to test antimatter particles, and for the first time, it passed, with lots of interference (which in the case of physics is a breakthrough and not a distraction). Antimatter is similar in many ways to regular particles we’re familiar with, like protons and electrons, except that they have the opposite charge and magnetic properties. When antimatter and matter mix, they combine and disappear in a huge flash of energy. This makes antimatter a rare and difficult material to study — but not impossible. The antimatter counterpart of an electron — called a positron — was put to the test in the traditional double-slit experiment in a new study published in Science Advances.

In the double-slit experiment, individual particles are shot through slits that are placed at a small distance from each other. When the particles — antimatter, in this case — reach either slit simultaneously, the test allows scientists to observe whether the matter interferes with itself after some distance. For instance, water waves and sound waves released from two parallel slits would clash at a certain point with each other. Light, too, is wave and particle by nature. Scientists used positrons from a radioactive material, which were accelerated to form a positron beam. While the traditional experiment has two simple slits, the positron beam was sent through two long, slit-shaped cavities with space between them. This setup helped magnify the effects the researchers needed to measure. When the positrons (antimatter) hit a detector, they formed a pattern, called the interference pattern, that are unique to waveforms. [caption id=“attachment_6607851” align=“alignnone” width=“1280”] A double-slit interference pattern created by sunlight passing through two slits. Image: Wikimedia Commons[/caption] This interference made by matter waves is at the heart of quantum physics. It’s a phenomenon that has been observed for many particles — from electrons to complex molecules. And now, researchers have demonstrated that antimatter, too, behaves like both waves and particles in nature. Decades ago, Albert Einstein predicted in his Theory of Relativity that gravity affects antimatter just like it affects all other matter. Experiments like (and unlike) the double-slit could open up new avenues to look at how antimatter behaves, including the effect of gravity on it.