Ettore Majorana

Ettore Majorana
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Name	Ettore Majorana
Caption	Ettore Majorana in the 1930s
Birth date	05 August 1906
Birth place	Catania, Kingdom of Italy
Death date	Presumed dead after 1938
Death place	Unknown
Nationality	Italian
Fields	Theoretical physics
Workplaces	University of Rome, University of Naples
Alma mater	University of Rome La Sapienza
Doctoral advisor	Enrico Fermi
Known for	Majorana equation, Majorana fermion, Neutrino theory

Ettore Majorana was a brilliant and enigmatic Italian theoretical physicist whose profound contributions to quantum mechanics and particle physics were overshadowed by his mysterious disappearance in 1938. A member of the renowned Via Panisperna boys under Enrico Fermi in Rome, he made seminal advances in neutrino theory and predicted the existence of Majorana fermions. His sudden vanishing at the age of 31, which has never been conclusively solved, transformed him into a legendary figure in the annals of 20th-century science.

Biography

Born into a prominent family in Catania, he demonstrated exceptional talent in mathematics and engineering from a young age. He moved to Rome to study engineering at the University of Rome La Sapienza but soon shifted his focus to physics, joining the influential group led by Enrico Fermi. This circle, which included figures like Franco Rasetti and Emilio Segrè, was instrumental in pioneering work on neutron bombardment and nuclear physics. After receiving his Laurea under Fermi's supervision, he traveled extensively, conducting research at Leipzig University with Werner Heisenberg and visiting the Niels Bohr Institute in Copenhagen. Despite his genius, he was known for his introverted personality, profound skepticism, and sporadic publication record, eventually accepting a professorship in theoretical physics at the University of Naples Federico II in 1937.

Scientific contributions

His most enduring work lies in the realm of relativistic quantum mechanics and symmetry in physics. In 1937, he formulated the Majorana equation, a relativistic wave equation that describes particles which are their own antiparticles. This theoretical construct led to the prediction of Majorana fermion, a class of particles distinct from the Dirac fermion described by Paul Dirac. His insights provided a potential explanation for the nature of the neutrino, suggesting it could be a Majorana particle, a hypothesis that remains a central question in experiments like those at the SNOLAB and CERN. He also made significant contributions to nuclear physics, developing the Majorana force model for nuclear interactions and performing calculations on the structure of atomic nuclei that impressed his peers, including Eugene Wigner.

Disappearance

On March 25, 1938, after withdrawing a large sum of money from his bank account in Naples, he boarded a Tirrenia Line ferry traveling to Palermo. He was last seen on board this vessel. Despite an extensive search ordered by Benito Mussolini and personally urged by Enrico Fermi, no definitive trace of him was ever found. Investigations and theories proliferated, ranging from suicide, a retreat into a monastery like the Certosa di San Giacomo on Capri, abduction, or a voluntary disappearance to avoid involvement in World War II weapons research. In 2015, the Rome Prosecutor's Office reopened the case, examining an alleged later photograph, but the inquiry concluded without solving the mystery.

Legacy and honors

His scientific legacy has grown substantially posthumously. The Majorana fermion has become a cornerstone of condensed matter physics, with potential quasiparticle manifestations observed in experiments on superconductivity and topological insulators, influencing research at institutions like the Massachusetts Institute of Technology and the Weizmann Institute of Science. The Majorana equation remains a fundamental text. In his honor, the Ettore Majorana Foundation and Centre for Scientific Culture was established in Erice, Sicily, and the prestigious Majorana Medal is awarded by the Italian Physical Society. The Gran Sasso National Laboratory hosts the CUORE experiment, which searches for neutrinoless double beta decay, a process that would confirm his neutrino hypothesis.

In popular culture

The intrigue surrounding his fate has inspired numerous works of fiction and speculation. He is a central character in Leonardo Sciascia's investigative book The Mystery of Majorana, which explores various disappearance theories. His story has been featured in films such as I Ragazzi di Via Panisperna and the documentary The Disappearance of Majorana. References to his work and mystery appear in television series like Doctor Who and novels by authors such as Andrea Camilleri. The concept of Majorana fermions is frequently cited in science fiction exploring advanced physics, including works by Greg Egan.

Category:Italian theoretical physicists Category:Missing people Category:1906 births