Colloquium: Majorana fermions in nuclear, particle, and solid-state physics
Steven R. Elliott and Marcel Franz
In nature one can associate to each particle an antiparticle with equal mass and opposite charge: to the electron there is the positron, to the proton there is an antiproton, etc. When they meet particles and antiparticles annihilate each other producing light in the process. Majorana fermions are particles with an identity crisis: they are their own antiparticles and hence they self-annihilate. Although they have been theoretically predicted to exist, they are recondite and only recently traces were found of their existence. In this Colloquium the nature of Majorana particles and their presence in several different branches of physics is discussed from nuclear to condensed matter.
Abstract: Reviews of Modern Physics