FERMI LATEST GIFT TO ITALY
After the war, Fermi was interested in the revival of science and technology in Italy. In 1948, he wrote to Prime Minister Alcide De Gasperi in support of an increase in research funds. In 1949, he participated in a conference in Como and visited the Olivetti factories in Ivrea, drawing attention to the emerging electronic technology. In 1950, he held a series of seminars in Rome and Milan. His memorable lectures at the Varenna School of the Italian Physics Society in 1954, just a few months before his death, are part of Fermi’s latest scientific gift to Italy. These are the words of the physicist Giulio Racah, in a seminar in Pisa in 1958, to recall Enrico Fermi’s suggestion on how to use considerable funding for the University of Pisa: “Make an electronic calculator”. So, the birth of computer science in Italy is therefore also due to Fermi. While favoring physics, Fermi never underestimated the importance of numerical computation. In fact, he was a pioneer in the use of electronic computers and one of the creators of numerical simulation methods.
“Fermi’s last gift to Italy” are the words used by Giulio Racah, a well-known Florentine physicist, in a seminar held in 1958 at the Institute of Physics of the University of Pisa to memorialize the suggestion made by Enrico Fermi to a group of illustrious Italian physicists—Gilberto Bernardini, Marcello Conversi and Giorgio Salvini—who had asked him for advice on how to use a large loan of about 150 million lire (almost 2.2 million euros today), destined for the University of Pisa.
In 1953, the Italian Physics Society (SIF) organized the first course of the International School of Physics in Varenna, a post-university summer school for young researchers. The initiative was due to the then President of SIF, Giovanni Polvani, who would later become President of the National Research Council (CNR). Thus began an activity that continues to this day with great success.
In the following year 1954, SIF organized the second course, directed by Giampietro (Gianni) Puppi, who had already directed the first course in 1953.
That second course, dedicated to the study of elementary particles and their interactions, saw the participation of Enrico Fermi and, in everyone’s memory, remained as a “memorable event”—in Puppi’s own words—”for a series of planetary conjunctions […] Who made it a theological summa of the physics of the pions… ”. But above all, because of impending Fermi’s death, which took place a few months later, “[…] a particular light reverberated on it”.
Fermi’s participation in the 1954 course was significant not only for his admirable lessons but also for the imprint he left on the consequent discussions and analyses of the perspectives of Italian physics.
During the course, a group of eminent Italian physicists, including Gilberto Bernardini, Marcello Conversi and Giorgio Salvini (the latter two from the University of Pisa), in discussion with Fermi, asked him for advice on how to best invest a large sum for research purposes (150 million lire, almost 2.2 million euros at present) which had become available to the University of Pisa after the tender for the construction of an electrosynchrotron had been lost. The competition was won by the then nascent Frascati National Laboratories of the National Institute of Nuclear Physics (INFN).
Letter from Enrico Fermi to Enrico Avanzi
In response his colleagues’ question in Varenna, Fermi had no doubts: Thanks to his direct experience with the first computers developed in America, he suggested designing and building an electronic computer to perform the complex but necessary calculations that would have enabled him to find the solution of linear problems and nonlinear ones that cannot be tackled analytically.
Soon after, in August 1954, just three months before his death, while on vacation in Trentino, Fermi formalized his suggestion by writing to the Rector of the University of Pisa, Enrico Avanzi.
Avanzi did not respond immediately because he too was on vacation in Trentino, and the letter was redirected to him from Pisa, but he said he was grateful to Fermi for the indication “that it will be kept in the utmost account”.
Thus began the activity that would lead to the construction of the first Italian electronic calculator: the CEP—Electronic Calculator Pisana.
The first modern electronic calculators date back to the late 1940s, the result of British and US research. In Italy, only in 1954 were the first two foreign computers purchased: in Milan by the Polytechnic and in Rome by the National Institute for Calculation Applications (INAC).
It was in that year that in Pisa, given the availability of a significant financial contribution from the provinces and municipalities of Pisa, Livorno and Lucca and after hearing Fermi’s opinion, that the enterprise of designing and building a calculating machine began.
In fact, the University of Pisa had also considered the purchase of a modern electronic calculator for scientific research, but it turned out that the cost of purchasing such a machine would have been too high. It was therefore decided to build one. For this purpose, the collaboration of research bodies and companies was also requested, with the support of the National Institute of Nuclear Physics (INFN) and the Olivetti Company.
Following the suggestion of Fermi and the support of INFN and Olivetti, in March 1955, the University of Pisa founded the Study Center on Electronic Calculators (CSCE), whose direction was entrusted to three professors: Marcello Conversi, Sandro Faedo and Ugo Tiberio. The first two years of work were dedicated to the design and development of a prototype with reduced performance compared to the original objectives: This was the Reduced Machine (MR), built in 1957 and made available to Italian researchers in the early months of 1958.
The Pisan Electronic Calculator (CEP) was completed in April 1961 and officially inaugurated on 13 November 1961 in the presence of the then President of the Republic Giovanni Gronchi.
Engineers made available by Olivetti also contributed to the development of the CEP, and Olivetti itself had opened its own laboratory in Barbaricina, a suburb of Pisa, directed by Mario Tchou, who led to the development, in 1958, of the Automatic Electronic Processor (ELEA), in which the thermionic tubes used in the CEP had been replaced by transistors.
In 1964, despite the success of ELEA (over 200 units were sold), and following a financial crisis, Olivetti decided to sell all its computer activities to General Electric. Thus ended the Italian production of medium-large electronic calculators.
Fermi was a pure physicist and always preferred to use physics and not mathematics to arrive at results. However, Fermi was also adept at making good approximate calculations with little or no actual data. In these cases, he began by making reasonable assumptions about the lower and upper limits of the quantities, which he then used in simple mathematical expressions to arrive at an estimate of the order of magnitude (i.e., the power of ten of the number that expresses the desired answer). Fermi was also known for the questions he posed to this end, which later became known as “Fermi problems”. A typical Fermi problem was, for example: “How many piano tuners are there in Chicago?”
In his Roman period, but also while in the United States, Fermi was never separated from his slide rule and was very proud of his ability to challenge his colleagues who used a mechanical calculator (Ettore Majorana in Rome) or even an electronic calculator (John von Neumann in Los Alamos).
When the physical approach was not possible, or when the calculations were too complex for his slide rule, Fermi did not disdain at all to resort to numerical calculations, which at the end of the 1920s began to be implemented on the first calculators. After all, Fermi has always been interested in technological developments: In 1949, he visited the Olivetti factory in Ivrea and already on that occasion drew Olivetti’s attention to emerging electronic technology.
His interest also extended to other technologies, such as motorcycling, and in 1954 he took advantage of his participation in the Varenna School to visit the Moto Guzzi factory in Mandello del Lario, just south of Varenna on the same shore of Lake Como, where he was presented with the latest model of “Galletto”, the first modern scooter.
In 1923, the Royal Physical Institute in via Panisperna acquired a series of various instruments, coming from Germany, as replacements for war damage. Among the instruments was a Brunsviga mechanical calculator. It is not clear whether that was the calculator used by Fermi, but it is certain that he had one from which he was not easily parted. Fermi continued to use the Brunsviga in the US as well. According to his colleague Herbert Anderson, it was precisely the Roman machine that Fermi had brought with him in 1939, on his journey through Stockholm.
Fermi was always attracted to new tools and, above all, he always wants to excel. So when Anderson started using a Marchant calculator, which proved to be significantly faster than the Brunsviga, Fermi adopted one too!
In the meantime, the first rudimentary but already revolutionary electronic calculators began to be developed. The ENIAC (Electronic Numerical Integrator And Computer) calculator was completed in 1946. Thanks to the work of Nicholas Metropolis and John von Neumann, the MANIAC (Mathematical Analyzer, Numerical Integrator, and Computer) calculator was developed starting in 1948 in Los Alamos and was completed in 1952. Fermi was among the first to want to use the new machine, so fast, and immediately became familiar with the calculation programs.
Attention to orders of magnitude, intervals and limits of validity, sensitivity and parametric analysis made Fermi, together with Stanislaw (Stan) Ulam and John von Neumann, one of the main scholars and supporters of the probabilistic method of simulations numerical, called the “Monte Carlo method”, and the practical importance of computers for numerical computation.
Two particularly relevant examples of Fermi’s use of numerical computation and MANIAC are:
– the analysis of the phase shifts of pion–proton diffusion events
– the analysis of nonlinearly coupled oscillators (Fermi–Pasta–Ulam problem).
After the war and his transfer to the University of Chicago (even if every summer Fermi returned to Los Alamos), Fermi continued to study the problems related to the transport of neutrons and the induced nuclear reactions, which had led him to the realization of the first controlled nuclear reaction and to the atomic pile. Calculations of neutron trajectories were done using probabilistic methods (i.e., the Monte Carlo method). To perform the calculations faster, Fermi had started using the ENIAC electronic calculator. But in 1947 it was decided to move ENIAC, which had been developed at the University of Pennsylvania, in Philadelphia, to its final location, the Ballistics Research Laboratory, in Maryland. The computer was thus unavailable for a certain period of time.
Informed of the problem by his colleagues at Los Alamos, Fermi devised an analog calculator that could generate the “genealogy” of a neutron, that is, describe the path of a neutron in a plane by determining the point of the next collision with the atoms of the materials making up the reactor.
In practice, this analog calculator, later called by all FERMIAC (by analogy with ENIAC and MANIAC, but also as an acronym for Fermi Analog Computer), was a trolley with a pen that could draw lines on a sheet that bore the outlines of the various materials that neutrons could pass through. Each section of the trolley’s path took place after setting some main parameters, such as the choice between “slow” and “fast” neutrons, or the characteristics of the material to cross. The setting was done by selecting the position of pointers on cylinders of different diameters.
The manufacture of the carriage, in brass, required considerable precision, in particular for the diameters of the ten cylinders. Fermi believed that an accuracy of at least 1 mil (one thousandth of an inch, i.e., 0.0254 mm or 25.4 micrometers) was necessary. So he decided not to make the truck himself but asked a colleague, Percy King, to build it and had him repeat the work because the first prototype was not of sufficient quality.
The FERMIAC performed its task very well for a couple of years, until ENIAC became available again, and MANIAC began to be usable too.