Ettore Majorana

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Ettore Majorana (1930s)

Ettore Majorana (born August 5, 1906 in Catania , Sicily / Italy ; lost at the end of March 1938) was an Italian physicist .

His most important work dealt with nuclear physics and relativistic quantum mechanics , with applications in particular in the theory of neutrinos . His disappearance in the spring of 1938 has sparked ongoing speculation about a possible suicide and its motives to this day.

The Majorana fermions are named after him.

Life

Childhood and youth

Ettore Majorana was born in Catania and attended school there. Even as a small child, he was considered a child prodigy in arithmetic - visitors to the family liked to demonstrate his skills to them, with Majorana usually hiding under a table to think. After the family moved to Rome , he attended the Liceo Torquato Tasso there. He skipped a class and graduated from high school in 1923. He began studying at the Engineering Faculty of the University of Rome. In 1927 Emilio Segrè , who later won the Nobel Prize, tried to persuade Majorana to move to the Institute for Experimental Physics newly founded by Enrico Fermi . After a conversation with Fermi, Majorana moved to his institute, where he passed his exam in 1929 with a thesis in the field of nuclear physics. It was during this time that he corresponded with Quirino Majorana , whose nephew he was.

Studies and first working group at Fermi

He joined the famous research group around Enrico Fermi, the “ragazzi di via Panisperna”. It included the theorists Gian-Carlo Wick , Ugo Fano , Giovanni Gentile , Giulio Racah and the experimenters Franco Rasetti , Giuseppe Cocconi , Emilio Segrè , Edoardo Amaldi and Bruno Pontecorvo . Majorana dealt mainly with the writings of Paul AM Dirac , Werner Heisenberg , Wolfgang Pauli , Hermann Weyl and Eugene Paul Wigner . He impressed Fermi at the first encounter with an analytical solution to a nonlinear equation in the Thomas-Fermi theory, the numerical solution of which had taken Fermi weeks himself. In addition, Majorana had been a master of mental arithmetic since childhood. Nobody in Fermi's group bothered to use a slide rule when Majorana was around. Fermi judged him that “no one in the world could solve a problem once posed better” than Majorana, and later put him on a par with physicists like Galileo or Newton. In the Fermi group, Laura Fermi describes him as follows: "Majorana, dark-eyed and of Spanish appearance, who was never satisfied with a first mathematical proof, but drove every investigation deeper and deeper [...] was called the Grand Inquisitor". On November 12, 1932, he took the exam in la libera docenza in fisica teorica , where the examination board under Enrico Fermi, Antonino lo Surdo and Enrico Persico certified that he had a complete command of theoretical physics ("una completa padronanza della fisica teorica") . Since he was a loner type, he also worked mostly on his own during his time at the institute. Laura Fermi said that he often scribbled new discoveries (also of the greatest importance) on cigarette packets or the like in the morning on the tram ride to the institute, but then indifferently discarded the notes after an oral presentation and never came back to them. In the beginning he mainly dealt with problems of the application of quantum mechanics in atomic and molecular physics.

Travel through Europe

In the winter of 1932/33 he met the American quantum physicist Eugene Feenberg (1906–1977) from Harvard University , with whom he traveled through Europe, initially to Leipzig . Because of the threatening situation in Germany at the beginning of National Socialism , Feenberg was recalled from his university. During his six months in Leipzig in 1933, Majorana met Heisenberg and attended his seminars. At the suggestion of Heisenberg, he published his work on nuclear physics in the Zeitschrift für Physik . Majorana traveled on to Copenhagen and met Niels Bohr there.

isolation

In 1933 he returned to Rome in poor health. He was still a member of the university, but mostly worked at home. In addition to physics, he dealt with economic policy, the naval policy of various countries and problems in shipbuilding. During this time he turned back to philosophy, especially the writings of Schopenhauer . He avoided contact with friends like Amaldi and his brother Luciano, neglected his appearance and rarely left his house.

professorship

In physics, after 1933 he only published one work on a symmetrical theory of electron and positron , namely in 1937 at the insistence of his friends on the occasion of a competition for a professorship . He had already completed the work in 1933. According to the Sicilian author Leonardo Sciascia , Majorana's application came as a complete surprise. The professorship positions had already been distributed in the order Wick , Racah , Gentile . The father Gentiles, a well-known philosopher who was close to the fascists, succeeded in organizing the “competition” in such a way that Majorana was previously appointed professor at the University of Naples . The appointment took place in 1937. He moved to Naples, but, in keeping with his shy character, lived very withdrawn, as he had in Rome. He suffered from stomach ulcers and ate almost nothing but milk. Although he continued to give lectures, only a few of his students were able to follow them because of the high level.

Disappear

Majorana's letter to Carrelli of March 26, 1938

In 1938 he wrote from Palermo in a letter to his friend Antonio Carrelli, the director of the Physics Institute in Naples, that he found life in general and his life in particular completely useless. He had made a decision that was "inevitable and without any bit of egoism". He also apologized for his sudden disappearance (scomparsa) and expressed the hope that he would be remembered, at least until that evening at 11 o'clock and possibly later. He revoked the letter, however, in a telegram to Carrelli from Palermo on March 25th. The sea rejected him, he said. In a letter to his relatives left at the hotel, he wrote that they should not mourn for more than three days. The letters are quoted from Sciascia .

Extremely worried about this letter, Carrelli alerted Fermi, who notified Majorana's brother. This flew immediately to Palermo, where Majorana had set out on the post boat from Naples on March 25 at around half past ten in the evening. According to the police investigation report, Majorana boarded the mail ship from Palermo back to Naples on March 26th. The return ticket has been handed in. However, fellow travelers like Professor Strazzeri could not clearly identify him. A nurse who knew him very well believes she saw him later in Naples, and a man who looks like him is said to have asked a Jesuit abbot for admission. After that his traces were lost. Shortly before his disappearance, he had given the manuscripts of his ongoing lectures to his student Gilda Senatore and withdrew all of his money, which today would be worth about $ 10,000. He had his passport with him.

The disappearance of the famous physicist triggered a major police search. His family put up a large sum of money for advice on his whereabouts. Even the Vatican was turned on because the family believed he could go into hiding in a monastery. All that remains are assumptions and speculations, such as those made by Leonardo Sciascia in his book. According to this, Majorana went into hiding in a southern Italian monastery because he foresaw moral complications through the development of the atomic bomb. Amaldi emphatically rejected this thesis in L'Espresso in 1975 . Recami took the view that Majorana had gone into hiding in Argentina and cited witnesses whom Tullio Regge believed to be credible after an interview. Recami saw a motive for this in Majorana's desire to escape the strong influence of his mother. Another motive for Majorana's disappearance is a long-standing murder trial against an uncle, which turned into a legal scandal . Sciascia, however, doubts this case will have any influence. - A German-language TV documentary was shot about this topic.

The physicist Francisco Guerra and the physics historian Nadia Robotti came to the conclusion in 2013, based on newly found documents (including a scholarship for a Jesuit missionary, which the family donated in 1939), that Majorana would most likely die before September 1939, but not immediately after his disappearance in March.

The investigation by the Roman Public Prosecutor's Office ended in 2015 and reports of a sighting in Venezuela

In 2008, a car mechanic named Francesco Fasani who emigrated to Venezuela and has since died published a book entitled "Chi l'a visto?" (Who saw him?) There the author reports that he met Ettore Majorana in the 1950s in Valencia ( Venezuela ) under the name of Bini. Majorana then lived in Valencia of her own free will from 1955 to 1959. Fasani further testified that he had heard orally at the time that Bini had a different name and was a very famous Italian scientist. There is also a photo of pheasant with bini. On the basis of this photo, the public prosecutor's office in Rome resumed the investigation in March 2011 and announced on February 4, 2015 that a photo comparison showed a good match between the anatomical characteristics of Bini's face and those of Majorana. Fasani also claimed to have found a postcard in Bini-Majorana's car that Majorana's uncle, the physicist Quirino Majorana, had written to the American physicist WG Conklin in 1920. The public prosecutor then closed further investigations into Majorana's disappearance. The Italian physicist Antonino Zichichi doubts the identification and continues to think that Majorana would go into hiding in an Italian monastery as the most likely. He claims to have learned this from the Bishop of Trapani when he was a regular guest at the Centro Ettore Majorana in Erice in the 1960s. He confided in him that he had been Majorana's confessor.

plant

His early work on atomic and molecular physics is characterized by the use of symmetry principles and close contact with experimental data. The work in variable magnetic fields arranged atoms   examines the Majorana Brossel effect and found application in experiments on the spin-flip of neutrons by Isidor Isaac Rabi and Felix Bloch mid-1940s.

In his Leipzig work On Nuclear Theory   , Majorana, who even before Chadwick's discovery, suspected the structure of nuclei from protons and neutrons, generalized Heisenberg's exchange interaction and was able to show the saturation of the binding energy in light nuclei without resorting to short-range repulsion like Heisenberg. Their presence was not confirmed until the 1950s.

His last published work from 1937, Symmetrical Theory of Electron and Positron   , with the real Majorana form of the Dirac matrices , lays the basis for numerous concepts named after him in elementary particle physics such as Majorana spinor and Majorana fermion , Majorana neutrino and Majorana Dimensions. In fact, Majorana specifically suggested describing neutrinos through his equations. A historical aspect of this work is the rejection of Dirac's hole theory , in which positrons were interpreted as holes in the image of the vacuum as a Dirac sea of infinitely many states of negative energy occupied by electrons.

Due to his reserved, self-sufficient nature, Majorana published only little and often only after intense pressure. In addition to his nine published works, the numerous original unpublished articles in his notebooks have been examined since the 1990s. Here, for example, there were anticipations of Feynman's path integral , works on the representations of the Lorentz group , some of which were published as the relativistic theory of particles with any internal angular momentum   , which Eugene Wigner anticipated, on the Thomas-Fermi theory of the atom and on the Fano theory in atomic physics. After memories of Wick, he also carried out unpublished work on field quantization long before 1933 , which anticipated Pauli's and Weisskopf's work from 1934.

His friend Gentile published Majorana's only published non-physical work in Scientia in 1942 , The Role of Statistical Laws in Physics and Social Sciences .

souvenir

In physics, in recognition of his work on the theory of neutrinos, the Majorana spinor was named after him, as well as related terms such as the hypothetical Goldstone boson majoron .

The Centro di Cultura Scientifica Ettore Majorana in Erice , Sicily, founded by Antonino Zichichi in 1963 as a conference center for theoretical physics, is named after him. There are also conferences on medicine, pharmacy, seismology, legal history, medieval archeology, and Friedrich II .

In 2006, 100 years after his birth, the Società Italiana di Fisica published an anthology of his work, and the Istituto Nazionale di Fisica Nucleare held a Majorana conference in Catania. The open access -Fachzeitschrift Electronic Journal of Theoretical Physics published a special volume and donated a year to be awarded price, the Majorana medal .

The Neutrino Ettore Majorana Observatory was named after Ettore Majorana. In 2015 an asteroid was named after him: (29428) Ettoremajorana .

literature

  • Salvatore Giacomuzzi, Gerhard Holzmüller, Gerhard Huemer: Ettore Majorana (1906–1938): An inventory 64 years after his disappearance. In: Reports on the history of science . 25, 2002, pp. 137-148.
  • Ginestra Amaldi: La vita e l'opere di E. Majorana ; Rome, Accademia di Lincei, 1966. Also in: Antonino Zichichi (Ed.): Strong and weak interactions ; 1966
  • Leonardo Sciascia : La scomparsa di Majorana Turin, Einaudi 1975. The Majorana case. A philosophical detective novel. With an afterword by Lea Ritter-Santini. Berlin, Seewald 1978, Busse-Seewald Verlag 1994, The Disappearance of Ettore Majorana , Berlin, Wagenbach, ISBN 3-8031-1218-4 . Wagenbach-Verlag 2011, ISBN 978-3-8031-2652-8 . Also in: One does not sleep with open doors , Zsolnay Verlag 1989 (2nd edition); dtv 1995 ( ISBN 978-3-423-11406-6 ).
  • Bruno Russo: Ettore Majorana - un giorno di marzo , Flaccovio Editore, Palermo 1997. Russo also made a television documentary, broadcast on RAI 3, Sicily, on December 18, 1990, and wrote a play about it in 1998
  • Erasmo Recami: Il caso Majorana , Di Renzo Editore, Roma, 2000
  • Burkhard Ziebolz: The secret life of Ettore Majorana ; fictional novel, KBV Verlag, 2000, ISBN 3-934638-53-8
  • Salvatore Esposito, E. Majorana jun., Recami, van der Merwe: Ettore Majorana: notes on theoretical physics ; Kluwer, New York 2003 (the notebooks 1927–1931, Volumetti )
  • Preziosi: Majorana - Lezioni all'Università di Napoli , Naples, Bibliopolis, 1987. Further lectures were discovered in 2005 and are to be published
  • Ignazio Licata: Majorana Legacy in Contemporary Physics , Di Renzo Editore, Roma, 2006
  • Francesco Guerra, Nadia Robotti: Ettore Majorana - aspects of his scientific and academic activity. Ed. della Normale, Pisa 2008, ISBN 978-88-7642-331-4 .
  • Salvatore Esposito: Ettore Majorana - unpublished research notes on theoretical physics. Springer, Berlin 2009, ISBN 978-1-4020-9113-1 .
  • João Magueijo : A Brilliant Darkness: The Extraordinary Life and Mysterious Disappearance of Ettore Majorana, the Troubled Genius of the Nuclear Age. Basic Books, 2009

Movie

Web links

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Remarks

  1. ↑ Laura Fermi: Mein Mann und das Atom (Atoms in the family), Diederichs Verlag 1956, p. 52
  2. ↑ z. B. Zichichi Ettore Majorana. Genius and Mystery , CERN Courier 2006
  3. ↑ Laura Fermi: Mein Mann und das Atom (Atoms in the family), Diederichs Verlag 1956, p. 54. Fermi himself was of course the "Pope".
  4. ↑ Laura Fermi: Mein Mann und das Atom (Atoms in the family), Diederichs Verlag 1956, p. 115
  5. ↑ Guerra, Robotti, The disappearance and death of Ettore Majorana, Physics in Perspective, Volume 15, 2013, pp. 160–177
  6. ^ Ester Palma: La Procura: Ettore Majorana vivo in Venezuela fra il 1955 e il 1959, Corriere della Sera, February 4, 2015
  7. ↑ published in: Nuovo Cimento Vol. 9, 1930, p. 43, (Italian)
  8. ↑ Ettore Majorana: About the core theory in Zeitschrift für Physik , Vol. 82 (1933), pp. 137-145 doi: 10.1007 / BF01341484 ; in David W. Brink (ed.): nuclear forces , wtb Paperback (1971) ISBN 3-528-06080-8
  9. ↑ Nuovo Cimento Vol. 14, p. 171
  10. ↑ Nuovo Cimento , Vol. 9, 1932, p. 335 (Italian)
  11. ↑ Scientia , Vol. 36, p. 55
  12. ↑ According to Russo, Majorana committed suicide in the "Schopenhauer" manner by becoming one with nature.
This version was added to the list of articles worth reading on June 21, 2007 .
personal data
SURNAME Majorana, Ettore
BRIEF DESCRIPTION Italian physicist
DATE OF BIRTH 5th August 1906
PLACE OF BIRTH Catania
DATE OF DEATH after 1938