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Ettore Majorana ( ,, uploaded 19 April 2013, retrieved 14 December 2019 ; 5 August 1906 – disappeared 25 March 1938) was an Italian theoretical physicist who worked on neutrino masses. Majorana was a supporter of Italian Fascism and a member of the National Fascist Party. He disappeared under mysterious circumstances after purchasing a ticket to travel by ship from Palermo to Naples.
The Majorana equation, , and Microsoft's device attempting to create topological qubits, Majorana 1, are named after him. In 2006, the Majorana Prize was established in his memory.
In 1938, Enrico Fermi was quoted as saying about Majorana: "There are several categories of scientists in the world; those of second or third rank do their best but never get very far. Then there is the first rank, those who make important discoveries, fundamental to scientific progress. But then there are the geniuses, like Galileo Galilei and Isaac Newton. Majorana was one of these."
Majorana was an enthusiastic and devout Catholic.
In this paper, Majorana and Gentile performed first-principles calculations within the context of this model that gave a good account of experimentally-observed core electron energies of gadolinium and uranium, and of the fine structure splitting of Cesium lines observed in optical spectra. In 1931, Majorana published the first paper on the phenomenon of autoionization in atomic spectra, which he called "spontaneous ionization"; an independent paper in the same year, published by Allen Shenstone of Princeton University, called it "auto-ionization", a name first used by Pierre Auger. This name, without the hyphen, has since become the conventional term for the phenomenon.
Majorana earned his Laurea in physics at the University of Rome La Sapienza in 1929. In 1932, he published a paper in the field of atomic spectroscopy concerning the behaviour of aligned atoms in time-varying magnetic fields. This problem, also studied by I. I. Rabi and others, led to development of an important sub-branch of atomic physics, that of radio-frequency spectroscopy. In the same year, Majorana published his paper on a relativistic theory of particles with arbitrary intrinsic momentum, in which he developed and applied infinite dimensional representations of the Lorentz group, and gave a theoretical basis for the mass spectrum of elementary particles. Like most of Majorana's papers, written in Italian, it languished in relative obscurity for several decades.It is discussed in detail by
Experiments in 1932 by Irène Joliot-Curie and Frédéric Joliot showed the existence of an unknown particle that they suggested was a gamma ray. Majorana was the first to interpret correctly the experiment as requiring a new particle that had a neutral charge and a mass about the same as the proton; this particle is the neutron. Enrico Fermi advised him to write an article on the topic, but Majorana did not. James Chadwick proved the existence of the neutron by experiment later that year, and he was awarded the Nobel Prize for this discovery.
Majorana was known for not seeking credit for his discoveries, considering his work to be trivial. He wrote only nine papers in his lifetime.
The had come to power in Germany as Majorana arrived there. He worked on a theory of the atomic nucleus (published in German in 1933) which, in its treatment of exchange forces, represented a further development of Heisenberg's theory of the nucleus. Majorana also travelled to Copenhagen that year, where he worked with Niels Bohr, another Nobel Prize winner, and a friend and mentor of Heisenberg.
In another letter from Copenhagen to a member of Enrico Fermi's group Giovannino, he expressed support for Nazi policies and applauded Hitler's sacking of civil servants from local administrations and his replacement of them with nationalist cadre:
Majorana recommended to his mother, who wanted to learn German, a newspaper that "became fascist overnight after Hitler imposed changes in the editorial board".
Majorana endorsed antisemitic views by suggesting that discrimination against Jews was justified as a means to "repress a socially harmful mentality," implying that such measures were necessary to make room for a new generation. Majorana wrote:
Professor of Italian Joseph Francese contends that Leonardo Sciascia's narrative regarding Majorana's disappearance is primarily a literary construct designed to stimulate debate over the ethical responsibilities of scientists rather than an accurate historical account. According to Francese, the story of Majorana's disappearance was a later dramatization by Sciascia that obscured the fact that Majorana was actively involved in the nationalist politics of the 1930s.
Majorana's last-published paper, in 1937, was an elaboration of a symmetrical theory of and . He predicted that in the class of particles known as fermions, there should be particles that are their own antiparticles. Solution of the Majorana equation yields those particles, now referred to as . There has been speculation that at least some part of the dark matter in the universe, which cannot be detected except by inference from its gravitational influence, may be composed of Majorana particles.
In 1938, at the age of 32, he became a full professor of theoretical physics at the University of Naples independently of the competition rules, without needing to take an examination because of his "high fame of singular expertise reached in the field of theoretical physics".
In Palermo, Majorana purchased a ticket on 25 March 1938 for a boat trip to return to Naples. He disappeared in unknown circumstances. Despite several investigations, his body was not found and his fate is still uncertain.
On the day of his disappearance, Majorana sent the following note from Palermo to Antonio Carrelli, director of the Naples Physics Institute:
Dear Carrelli,
I made a decision that has become unavoidable. There isn't a bit of selfishness in it, but I realize what trouble my sudden disappearance will cause you and the students. For this as well, I beg your forgiveness, but especially for betraying the trust, the sincere friendship, and the sympathy you gave me over the past months.
I ask you to remember me to all those I learned to know and appreciate in your Institute, especially Sciuti: I will keep a fond memory of them all at least until 11 pm tonight, possibly later too.
— E. Majorana
This was followed rapidly by a telegram from Majorana cancelling earlier travel plans. Apparently, he then bought a ticket to travel by ship from Palermo to return to Naples. He was never seen again.
Italian philosopher Giorgio Agamben published a book in 2016 that examines the case of Majorana's disappearance.
On 4 February 2015, the Rome Attorney's Office released a statement declaring that Majorana had been alive between 1955 and 1959, living in Valencia, Venezuela. Based upon new evidence, these last findings were the foundation for the office to declare the disappearance case officially closed, having found no criminal evidence related to his disappearance, determining that it probably was a personal choice, and a presumption that he had emigrated to Venezuela.
An international conference on "Ettore Majorana's legacy and the Physics of the XXI century" was held in commemoration of the centennial of Majorana's birth in Catania, 5–6 October 2006. The conference proceedings with articles of highly ranked international scientists A. Bianconi, D. Brink, Nicola Cabibbo, R. Casalbuoni, G. Dragoni, S. Esposito, E. Fiorini, M. Inguscio, R. W. Jackiw, Luciano Maiani, R. Mantegna, E. Migneco, R. Petronzio, B. Preziosi, R. Pucci, E. Recami, and Antonino Zichichi have been published by POS Proceedings of Science of SISSA, edited by Andrea Rapisarda (chairman), Paolo Castorina, Francesco Catara, Salvatore Lo Nigro, Emilio Migneco, Francesco Porto, and Emanuele Rimini.
A commemorative book of his nine collected papers, with commentary and English translations, was published by the Italian Physical Society in 2006.
Also to commemorate the centenary, the Electronic Journal of Theoretical Physics (EJTP) published a special issue of twenty articles dedicated to the modern development of Majorana's legacy. The EJTP also established a prize in his memory to mark his centenary. The Majorana Medal or Majorana Prize is an annual prize for researchers who have shown peculiar creativity, critical sense, and mathematical rigour in theoretical physics—in its broadest sense. The recipients of the 2006 Majorana Prize were (University of Bergamo and INFN) and George Sudarshan (University of Texas); of the 2007 Majorana Prize: Lee Smolin (Perimeter Institute for Theoretical Physics, Canada), (Centro Interdipartimentale di Scienze Cognitive, Università di Pavia and Dipartimento di Psicologia, Università di Pavia Piazza Botta, Italy) and (Dipartimento di Fisica, Università La Sapienza, Roma, Italy).
Commemoration of centenary
The year 2006 marked Majorana's centenary.
See also
Further reading
External links
Categories: 1906 Births, 1930s Missing Person Cases, 20th-century Italian Physicists, Missing Italian People, Missing Person Cases In Italy, People From Catania, People From Valencia, Venezuela, Sapienza University Of Rome Alumni, Academic Staff Of The Sapienza University Of Rome, Scientists From Sicily, University Of Naples Federico Ii Alumni, Year Of Death Unknown
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