Majorana

Ettore Majorana was an Italian theoretical physicist whose work helped shape ideas about the nature of particles and antiparticles. Born in 1906 in Catania, Sicily, he studied and conducted research in the Roman physics community, becoming associated with Enrico Fermi's group in the 1930s. Majorana is best known for proposing the concept of fermions that are their own antiparticles, a notion now known as Majorana fermions.

In 1937 he published a paper presenting a symmetric theory of the electron and the positron, introducing field equations that allow a neutral spin-1/2 particle to be described by real, rather than complex, spinor fields. This work also led to what is called the Majorana mass term in particle physics, a framework in which neutrinos—if they are Majorana particles—could be their own antiparticles. Majorana’s ideas influenced subsequent developments in quantum field theory and the study of neutrino masses, with implications for lepton number violation and rare processes such as neutrinoless double-beta decay.

Majorana disappeared in March 1938 while traveling to Sicily and was never found; his fate remains unknown and he was presumed dead in the years that followed. The abrupt end of his career did not diminish his impact: his theoretical insights continue to influence both high-energy physics and condensed matter physics, where Majorana fermions also appear as emergent quasiparticles in certain superconducting systems.

Today, the term Majorana is used in multiple contexts, from fundamental particle theory to the study of quantum materials. The ongoing experimental effort to determine whether neutrinos are Majorana particles remains a central question in neutrino physics.