Physicists Discover Particle That's Both Matter and Antimatter
The elusive antimatter's existence was officially confirmed relatively recently, but physicists from Princeton University have already found evidence of a new type of particle that is simultaneously matter and antimatter.
According to predominant theories in physics, every particle in the universe has a corresponding antiparticle, which has exactly the same mass and opposite charge. When a particle meets its antiparticle, both are completely annihilated. Almost all of the observable universe is composed of matter, which led physicists to question how this asymmetry between matter and antimatter arose. This is one of the greatest unanswered questions in all of physics, although there is speculation that large deposits of antimatter may exist in faraway galaxies as a result of cosmic inflation.
In 1937, less than a decade after the first proposal of antimatter, physicist Ettore Majorana predicted the existence of a particle that was its own antiparticle, now called the Majorana fermion, or Majorana particle. These particles consist of a matter-antimatter particle pair that are uncharged and identical, and so do not annihilate upon contact. After almost eighty years, Majorana's theory has been confirmed, as the new study shows that Majorana particles can exist inside a superconductor.
A superconductor is a material that allows for the free movement of electrons, and therefore the conduction of electricity, without any resistance. The research team used the particular properties of the superconductor in order to cause electrons to take on the properties of antielectrons, thereby behaving as their own antiparticles.
Theoretical physicist Leo Kouwenhoven said, "The great thing about Majoranas is that they are potentially a new class of particle. If you find a new class of particles, that really would add a new chapter to physics."
Since the Majorana particles are "emergent particles," in the sense that they emerged from the properties of the superconductor, they cannot exist in a vacuum, but can only exist inside the superconductor. This somewhat limits their applicability, but scientists are already theorizing potential uses in quantum computing. One of the major obstacles to computers capable of quantum speed calculations is the tendency of quantum particles to become entangled, or to collapse as a result of the behavior of other particles. Majorana particles serving as bookends at each end of a chain of quantum particles could effectively prevent this phenomenon.