“the first afternoon I spent with Enrico”: Ibid.
Segrè notes that Fermi in later: Segrè, Enrico Fermi, 33.
“He was younger than I was”: American Institute of Physics, “Oral History Interviews: George Uhlenbeck—Session III,” April 5, 1962, https://www.aip.org/history-programs/niels-bohr-library/oral-histories/4922–3.
Much of Fermi’s success in Leiden: Letter from Fermi to Maria Fermi, Leiden, October 27, 1924. In Fermi folder, Department of Physics library, University of Pisa.
Ehrenfest, a close friend of Einstein: Kumar, Quantum, 169.
Fermi kept a group photo of Einstein: Private communication with Roberto Vergara Caffarelli, whose book, Enrico Fermi, Immagini e domumenti (2001), includes the photo on page 53.
Einstein clearly impressed the young man: Letter from Fermi to Maria Fermi, Leiden, October 27, 1924. In Fermi folder, Department of Physics library, University of Pisa.
Fermi expressed annoyance: Telegdi in Orear, Enrico Fermi, 98, and in Shils, Remembering the University of Chicago, 126. Also, Geoffrey Chew, interview with author, May 6, 2014.
Fermi got to work quickly: CPF I, 134–137.
CHAPTER FOUR: QUANTUM BREAKTHROUGHS
The breakthroughs in quantum theory: What follows over the next two chapters is an extremely simplified summary of a highly complex history. Readers with an interest in finding out more can go to many sources, including Van Der Waerden, Sources of Quantum Mechanics; Kumar, Quantum; and Fernandez and Ripka, Unravelling the Mystery of the Atomic Nucleus.
Physicists began to call the heavy central: “Heavy” in a relative sense only; most of an atom’s mass is in the nucleus, but a nucleus is extremely small—for a hydrogen atom, on the order of one-millionth of a billionth of a meter across (a distance known as a fermi).
although in most important details: Bohr thought electrons orbited in circular orbits, but we know now that they don’t really “orbit” at all—they seem to be everywhere at once, and the shape of the “orbit” can be quite exotic, certainly not circular. Hence the standard term “orbital.”
One such phenomenon was called: For this discovery, Zeeman shared the 1902 Nobel Prize in Physics with Hendrik Antoon Lorentz.
That he continued to keep abreast: CPF I, 134. Published in Italian in 1925.
With the great theorist Arnold Sommerfeld: Sommerfeld’s productive career included many important discoveries, most notably the constant that describes the relative strength of the electromagnetic force, what physicists call the “fine structure constant.” Over more than three decades at the University of Munich he sponsored the PhD work of a number of future Nobel Prize winners, including not only Pauli but also Werner Heisenberg and Peter Debye, and influenced the early studies of a number of others, including Haldan Hartline, Linus Pauling, and Isidor Isaac (I. I.) Rabi. Nominated for the Nobel Prize himself some eighty-four times—more than any other physicist—he sadly never won it.
As a theorist Pauli was perhaps: See Rudolf Peierls’s colorful and readable brief biography in Peierls, Atomic Histories, 3–17.
Pauli also had a legendary mean streak: Miller, 137: Jung, Pauli. See also Gross, “On the Calculation of the Fine-Structure Constant,” 9.
Pauli was born Catholic: Heisenberg, Physics and Beyond, 86–87.
He had a deep mystical streak: Meier, Atom and Archetype.
He was also a man of obsessions: Kumar, Quantum, 164; Pauli, “Remarks on the History of the Exclusion Principle,” 214.
angular momentum in opposite directions: Quantum spin should not be confused with classical spin. Quantum spin is the intrinsic angular momentum of the particle; the particle should not be thought of as spinning like a top, although a spinning top is perhaps the most obvious example of angular momentum.
It was picked up again: See Kumar, Quantum, 169–175, and S. A. Goudsmit, “The Discovery of the Electron Spin,” http://www.lorentz.leidenuniv.nl/history/spin/goudsmit.html.
“the strangest man”: Farmelo, The Strangest Man.
Paul Adrien Maurice Dirac was the baby: Kumar, Quantum, 198–199; Farmelo, The Strangest Man, 86–87, 101. Dirac saw the connection between Heisenberg’s ideas and Poisson brackets used in classical mechanics.
Dirac was, in some sense: Heisenberg, Physics and Beyond, 86–87.
His PhD thesis was impressive: Kumar, Quantum, 197.
Almost immediately, Dirac was propelled: Though he never contributed fundamentally in experimental fields, he pursued an engineering degree prior to his shift to physics and always showed a strong interest in the experimental side of the field.
His was the first PhD degree: Kumar, Quantum, 230.
CHAPTER FIVE: OF GECKOS AND MEN
Perched on a low hill: The elders of Florentine physics, including Antonio Garbasso, the head of the institute who was also, surprisingly, the mayor of Florence, chose the site because of its connection to Galileo, who lived the last years of his life in the Villa “il Gioiello” (the jewel), a ten-minute walk uphill from the Istituto di Fisica. The villa still exists and now belongs to the University of Florence. My thanks to Andrea Gambassi for this information.
Now he was delighted to take on: Casalbuoni, Frosali, and Pelosi, Enrico Fermi a Firenze, 29ff.
The notes for his mechanics lectures: Often students who had learned a bit of calligraphy prepared class lecture notes and sold them for some extra pocket money. The lovely notes on Fermi’s lectures were preserved by two of his students, Bonanno Bonanni and Paolo Pasca, and have been published recently in a fascinating volume on Fermi’s years in Florence. See ibid., 73ff.
The two pranksters noted: Laura Fermi, Atoms, 37–38.
Together they hatched a plan: AIP, “Oral History Interviews: Franco Rasetti and Enrico Persico.” Rasetti claimed that the target of the prank was the wife of the janitor, who served food at the cafeteria, but it would have been difficult to frighten her without also frightening all the other young women serving there.
A paper he wrote in January 1924: CPF I, 124.
He was struggling with the application: Belloni, “On Fermi’s Route to the Fermi-Dirac Statistics”; Parisi, “Fermi’s Statistics,” 67–74; Sebastiani and Cordella, “Fermi toward Quantum Statistics,” 71–96.
“The quantum states of an atom”: Bethe, The Santa Fe New Mexican, January 6, 1955, 2.
“On the Quantization of a Perfect”: Belloni, “On Fermi’s Route to the Fermi-Dirac Statistics,” discusses the meteorological aspects of the story.
It took him the rest of the year: CPF I, 178–195.
The paper had an immediate impact: It may well not have been Fermi’s primary purpose in doing so, but the implications for understanding degeneracy were clear to theorists around the world and provided the first, immediate applications. Belloni, “On Fermi’s Route to the Fermi-Dirac Statistics.”
Word spread as far as England: Farmelo, The Strangest Man, 101.
Dirac developed an interest in the problem: Ibid., 105. Also Kragh, Dirac.
“In your interesting paper”: Quoted in Kragh, Dirac, 36.
“When I looked through Fermi’s paper”: Ibid.
As is the case with many important developments: Schuking, “Jordan, Pauli, Politics, Brecht, and a Variable Gravitational Constant,” 26.
Fermi’s candidacy fell victim: Glick, The Comparative Reception of Relativity, discusses the challenges the acceptance of relativity theory faced throughout Europe.
Levi-Civita, of course, was one: Segrè, Enrico Fermi, 42.
Pontremoli, to Milan: Pontremoli went on to establish the Institute of Physics at the University of Milan. He died tragically young, at the age of thirty-two, during the ill-fated Italia dirigible flight to the North Pole led by General Umberto Nobile. Pontremoli was on board to help measure the magnetic field of the earth as well as to detect cosmic rays. On its return trip to base camp, the dirigible crashed onto the ice. Some of the unlucky crew survived, but some, like Pontremoli, were never found and were presumed de
ad.
“That Fermi had been intensely interested”: Segrè, Enrico Fermi, 39–40.
as Amaldi once suggested: See TWOEF, Amaldi interview.
“he moves with complete assurance”: Quoted in Segrè, Enrico Fermi, 45. Emphasis added.
CHAPTER SIX: FAMILY LIFE
The years Fermi spent in Rome: Holton, “Striking Gold in Science,” covers this period and points out the fact, disconcerting though it may be, that all these achievements took place under, and with the support of, a repugnant political system.
On Saturdays, Fermi returned: Laura Fermi, Atoms, 42ff., is the only account of what must have been quite remarkable gatherings. Given the overlapping professional interests of these men, it would seem likely that many important developments in algebraic geometry and other fields were first hashed out leisurely at Saturday discussions in Castelnuovo’s parlor.
young woman named Ginestra Giovene: Laura Fermi, Atoms, 45. She would also become Laura Fermi’s closest friend.
Fermi would also play “director”: Laura Fermi, Atoms, 41, and interview with Ugo Amaldi, June 8, 2016. Fermi at one point suggested that Edoardo Amaldi play Greta Garbo, a suggestion Amaldi accepted “with good grace.”
“We could see nothing of interest”: Laura Fermi, Atoms, 66.
Alexandria in the Enciclopedia Italiana: Laura Fermi, Atoms, 67. The Enciclopedia Italiana was a favored project of Mussolini, who tapped industrialist and cultural patron Giovanni Treccani to edit it. It brought together outstanding scholars throughout Italy in every field; it included important nonfascists on its authors list. When Fermi received an offer to become a professor in Zurich in 1928, Mussolini persuaded him to stay by arranging a consulting job for him on the Enciclopedia to supplement his income.
“You mean to say”: Laura Fermi, Atoms, 10–11.
“He wanted a tall, strong girl”: Ibid., 52.
Its egg-yolk yellow color: Ibid., 52–53.
“Patiently I learned the mathematical instruments”: Ibid., 59–60.
Published in 1936 and aimed at: EFREG, 57:2.
The project worked and by 1941: Goudsmit, “The Michigan Symposium in Theoretical Physics,” 178–182.
The two Dutchmen invited Fermi: CPF I, 401–445.
he mispronounced a few words in such a wonderful: After the war, a young Fausta Segrè, Emilio’s daughter, corrected Fermi’s pronunciation of the word battleship as “bottle-sheep.” Fausta Segrè Walsby, interview with author, June 2, 2016.
“There seemed to be a total incomprehension”: Laura Fermi, Atoms, 80–81.
She loved it there: Ibid., 94ff.
“There is no democracy in physics”: Greenberg, Politics of Pure Science, 43.
emphasized by Italian scholar Giovanni Battimelli: Battimelli, “Funds and Failures,” 169–184.
CHAPTER SEVEN: THE ROME SCHOOL
This “Rome School” of physics: Holton gives the best overview of the school and its development, in three classic studies: “Striking Gold in Science”; The Scientific Imagination, 155–198; and Victory and Vexation, 48–64. See also Segrè, Enrico Fermi, 46–100; also, passim, Bernardini et al., Proceedings of the International Conference “Enrico Fermi and the Universe of Physics”; Bernardini and Bonolis, Enrico Fermi; and Segrè, “The Rome School,” in Stuewer, Nuclear Physics in Retrospect, 35–62.
Its hallmarks were a balance of theory: Holton, “Striking Gold in Science.”
Fermi invited Segrè to attend the 1927: Laura Fermi, Atoms, 44.
He also had a fiery temper: Laura Fermi writes (Laura Fermi, Atoms, 46) that during one seminar session in Fermi’s office, Segrè got himself so worked up because the other attendees wouldn’t let him speak that he pounded Fermi’s desk and left a hole in it. This author has examined the desk and has seen no such hole, so either there was another desk or perhaps Laura Fermi was exaggerating; regardless, it is clear he had a temper.
Majorana was by all accounts the brightest: Magueijo, Brilliant Darkness, gives a thorough, if somewhat idiosyncratic, perspective on Majorana’s life and work.
“Fermi’s seminar was always improvised”: Segrè, Enrico Fermi, 51–52.
Ginestra wrote that students learned: Laura Fermi, Atoms, 46.
“that moved slowly but knew no obstacles”: Segrè, Enrico Fermi, 56.
“When the four came together”: Laura Fermi, Atoms, 44.
“certain playfulness, a naïve love”: Ibid., 45.
When Ginestra first encountered the private seminar: Ibid., 46.
Segrè tells the story of a member: Segrè, Enrico Fermi, 52.
One problem that Corbino and Fermi faced: Segrè is at pains to emphasize that this did not seem to be an explicit objective for Fermi, but there is little doubt, given the sequence of events, that Corbino had this as a conscious objective and shared these thoughts with Fermi. It is inconceivable that Fermi did not share Corbino’s objective.
most important presentation was that of Bohr: Bohr believed that every phenomenon of physics could be viewed in two complementary ways: the classic example is light behaving as both a particle and a wave.
“May I introduce the applications”: Pauli to Rasetti, October 30, 1956 (Amaldi Archives). It might have been more apt to say “May I introduce the exclusion principle to its most important application.”
Rasetti, reflecting on the importance: American Institute of Physics, “Oral History Interviews: Franco Rasetti and Enrico Persico,” interviewed by Thomas S. Kuhn, April 8, 1963, https://www.aip.org/history-programs/niels-bohr-library/oral-histories/4995.
Lo Surdo had made: Leone, Paoletti, and Robotti, “A Simultaneous Discovery.”
Corbino and Lo Surdo were personal rivals: The author thanks Francesco Guerra and Nadia Robotti for this and other points regarding Lo Surdo. Private communication with author, February 27, 2016.
Lo Surdo may not have won: Laura Fermi, Atoms, 69ff. She refers to Lo Surdo by a pseudonym, “Mr. North.”
The story does not hold up: Guerra and Robotti, private communication with author, February 27, 2016.
He also wanted, somewhat naïvely: In these early years he was far more tolerant of dissent than he was in later years. However, many distinguished figures of Italian culture wanted nothing to do with him.
“INCIPIT VITA NOVA”: EFDG, 2.
Fermi was by far the youngest: https://en.wikipedia.org/wiki/Royal_Academy_of_Italy.
CHAPTER EIGHT: BETA RAYS
gave rise to density functional theory: Density functional theory is a computational technique that uses electron density to describe the electron structure of many-bodied systems. It is a key technique in modern condensed matter physics, chemistry, and materials science. See “Density Functional Theory,” Wikipedia, last modified January 9, 2017, accessed January 30, 2017, https://en.wikipedia.org/wiki/Density_functional_theory.
“The Calculation of Atomic Fields”: For his part, Thomas failed to credit either Fermi or Dirac.
Some Italian historians: They point out that Thomas’s work was limited to an electron in its ground state, whereas Fermi’s approach was more general. Francesco Guerra and Nadia Robotti, private communication with author, February 3, 2017.
The eponymous Maxwell’s equations: Forbes and Mahon, Faraday, Maxwell, and the Electromagnetic Field, for a comprehensive discussion of Faraday and Maxwell and their achievements.
He was a mere twenty-four: A few years later Dirac pulled together all his thoughts on the subject in a book called The Principles of Quantum Mechanics (Oxford, 1930, revised four times). It stands even today as one of the most important treatments of the subject.
Fermi understood the importance: Segrè, Enrico Fermi, 55.
The private seminars at Via Panisperna: Ibid. See also CPF I, 305.
This description of how an atom: CPF I, 401–402.
“a masterpiece, instructive and refreshing”: Wilczek, “Fermi and the Elucidation of Matter,” 42.
“Many of you, like myself”: Bethe, “Memorial S
ymposium,” 253.
“He disliked complicated theories”: Wigner, Symmetries and Reflections, 254.
Beta radiation seemed to violate: It seemed to violate other conservation laws as well, most notably quantum spin conservation. See Guerra, Leone, and Robotti, “When Energy Conservation Seems to Fail.”
Some physicists surrendered: Bohr, “Atomic Stability and Conservation Laws,” 119–130.
He called this imaginary particle: Amaldi later claimed credit for suggesting the name to Fermi, who adopted it at once, and the rest of the world followed suit. Segrè suggests that the name “neutrino” was first used by Fermi at the Rome conference of October 1931; however, Chadwick had yet to discover the neutron, so there would have been no need to differentiate Pauli’s particle from Chadwick’s.
“better not to think about”: Cited in Pauli’s letter, “Open Letter to the Group of Radioactive People at the Gauverein Meeting in Tübingen,” Physics Institute, Zurich, December 4, 1930, http://microboone-docdb.fnal.gov/cgi-bin/RetrieveFile?docid=953;filename=pauli%20letter1930.pdf.
“A Tentative Theory of Beta Rays”: In recognition of the importance of this paper, there is an enormous amount of literature on its contribution to modern physics. For a quick sample, see Konopinski, “Fermi’s Theory of Beta-Decay”; Cabibbo, “Fermi’s Tentativo and Weak Interactions,” 305–316; Cabibbo, “Weak Interactions,” 138–150.
When the neutron is changed: Fermi’s original paper did not identify the neutrino emerging from the conversion of a neutron to a proton as an antineutrino; that part of the theory came a bit later.
Fermi sent the paper to the Italian journal: CPF I, 551–590.
This story is so central: “Fermi’s Interaction,” Wikipedia, last updated July 19, 2017, https://en.wikipedia.org/wiki/Fermi%27s_interaction#History_of_initial_rejection_and_later_publication.
In fact, no such public statement: This author has reviewed the digital online archives and has found no such statement; the archivist of Nature confirmed in private communication that none was ever printed.
It is unfortunately impossible: This was confirmed both by the current archivist of Nature and by Laura Garwin, the daughter of Fermi’s graduate student and colleague Richard Garwin, who worked on the staff of Nature for several years and who searched unsuccessfully for the correspondence regarding the beta decay paper. Richard Garwin, interview with author, May 22, 2014.
The Last Man Who Knew Everything Page 47