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Enrico Fermi

(September 29, 1901November 28, 1954) Enrico Fermi was an Italian physicist most noted for his work on the development of the first nuclear reactor, and for the development of quantum theory. Fermi won the 1938 Nobel Prize in Physics for his work on induced radioactivity.

Physics in Rome

Enrico Fermi was born in Rome, Italy. His father was Alberto Fermi, a Chief Inspector of the Ministry of Communications, and his mother was Ida de Gattis. As a young boy he enjoyed learning physics and mathematics and shared his interests with his brother Giulio. When Giulio died unexpectedly of a throat abscess in 1915, Enrico was distraught, and immersed himself into scientific study to distract himself. According to his own account, he would walk in front of the hospital where Giulio died each day, until he became inured to the pain. Later, Enrico befriended another scientifically inclined student named Enrico Persico, and the two together engaged in scientific projects such as building gyroscopes, and measuring the magnetic field of the earth. Fermi's interest in physics was further encouraged when a friend of his father's gave him several books on physics and mathematics, which he read and assimilated.

Fermi received his undergraduate and doctoral degree from the Scuola Normale Superiore in Pisa. There was an entrance exam which candidates had to take in order to enter the prestigious institute, which included an essay. For his essay, the seventeen year old Fermi chose to derive and solve the Fourier analysis based partial differential equation for waves on a string. The examiner interviewed Fermi and concluded that his essay would have been commendable even for a doctoral degree. At the Scuola Normale Superiore, Fermi teamed up with a fellow student named Franco Rasetti who he use to indulge in light hearted pranks with. Later, Rasetti became Fermi's close friend and collaborator.

Fermi's Ph.D advisor was Luigi Puccianti. In 1924 Fermi spent a semester in Gttingen, then stayed for a few months in Leiden with Paul Ehrenfest. When he was only 24 years old, Fermi took a professorship in Rome (the first for theoretical physics in Italy, created for him by professor Orso Maria Corbino, director of the Institute of Physics). Corbino helped Fermi in selecting his team, which soon was joined by notable minds like Edoardo Amaldi, Bruno Pontecorvo, Franco Rasetti and Emilio Segr. For the theoretical studies only, Ettore Majorana also took part in what was soon nicknamed "the Via Panisperna boys" (after the name of the road in which the Institute had its labs). The group went on with its now famous experiments, but in 1933 Rasetti left Italy for Canada and the United States, Pontecorvo went to France and Segr left to teach in Palermo.

During their time in Rome, Fermi and his group made important contributions to many practical and theoretical aspects of physics. Some of these include Fermi-Dirac statistics, the theory of beta decay, and the discovery of slow neutrons, which was to prove pivotal for the working of nuclear reactors. His group also systematically bombarded elements with neutrons, and during their experiments with Uranium, narrowly missed observing nuclear fission. At that time, fission was thought to be improbable, if not impossible, mostly on theoretical grounds.

While people expected elements with higher atomic number to form from neutron bombardment of lighter elements, nobody expected neutrons to have enough energy to actually split a heavier atom into two light element fragments. However, the chemist Ira Noddack had criticised Fermi's work and had suggested that some of his experiments could have produced lighter elements. At the time, Fermi dismissed this possibility on the basis of calculations.

Fermi was well-known for his simplicity in solving problems. Whenever possible, he avoided complicated mathematics and obtained quick results based on order of magnitude estimates. This quality was acknowledged by and influenced many physicists who worked him, such as Hans Bethe, who spent two semesters working with Fermi in the early 1930s. Fermi also meticulously recorded his calculations in notebooks, and later used to solve many new problems that he encountered based on these earlier known problems.

When Fermi submitted his famous paper on beta decay to the prestigious journal Nature, the journal's editor turned it down because "it contained speculations which were too remote from reality". Thus, Fermi saw the theory published in Italian and in German before it was published in English.

He never forgot this experience of being ahead of his time, and used to tell his protgs: "Never be first; try to be second".

Nobel Prize & The Manhattan ProjectFermi remained in Rome until 1938.

In 1938, Fermi won the Nobel Prize in Physics for his "demonstrations of the existence of new radioactive elements produced by neutron irradiation, and for his related discovery of nuclear reactions brought about by slow neutrons".

Fermi (bottom left), Szilrd (second from right on bottom), and the rest of the pile team.After Fermi received the Nobel prize in Stockholm, he, his wife Laura, and their children immigrated to New York. By this time, the Fascist government in Italy had instituted anti-Semitic laws, and Fermi's wife, Laura Capon, was Jewish. Soon after his arrival in New York, Fermi began working at Columbia University.

At Columbia, Fermi verified the initial nuclear fission experiment of Hahn and Fritz Strassmann (with the help of Booth and Dunning). Fermi then began studies that led to the construction of the first nuclear pile Chicago Pile-1.

Fermi recalled the beginning of the project in a speech given in 1954 when he retired as President of the American Physical Society. Fermi's ID badge photo from Los Alamos."I remember very vividly the first month, January, 1939, that I started working at the Pupin Laboratories because things began happening very fast. In that period, Niels Bohr was on a lecture engagement at the Princeton University and I remember one afternoon Willis Lamb came back very excited and said that Bohr had leaked out great news. The great news that had leaked out was the discovery of fission and at least the outline of its interpretation. Then, somewhat later that same month, there was a meeting in Washington where the possible importance of the newly discovered phenomenon of fission was first discussed in semi-jocular earnest as a possible source of nuclear power."

An image from the Fermi-Szilrd "neutronic reactor" patent.In August of 1939 Le Szilrd prepared and Albert Einstein signed the famous letter warning President Franklin D. Roosevelt of the probability that the Nazis were planning to build an atomic bomb. Because of Hitler's September 1 invasion of Poland, it was October before they could arrange for the letter to be personally delivered. Roosevelt was concerned enough that the Uranium Committee was assembled and awarded Columbia University the first atomic energy funding of US$ 6,000. However, due to bureaucrat's fears of foreigners doing secret research, the money was not actually issued until Szilrd implored Einstein to send a second letter to the president in the spring of 1940.

The money was used in studies which led to the first nuclear reactor Chicago Pile-1, a massive "atomic pile" of graphite bricks and uranium fuel which went critical on December 2, 1942, built in a squash court under Stagg Field, the football stadium at the University of Chicago. This experiment was a landmark in the quest for energy, and it was typical of Fermi's brilliance. Every step had been carefully planned, every calculation meticulously done by him. When man first achieved the first self sustained nuclear chain reaction, a coded phone call was made to one of the leaders of the Manhattan Project, James Conant: 'The Italian navigator has landed in the new world... The natives were very friendly'. The chain-reacting pile was important not only for its help in assessing the properties of fission needed for understanding the internal workings of an atomic bomb but because it would serve as a pilot plant for the massive reactors which would be created in Hanford, Washington, which would then be used to "breed" the plutonium needed for the bombs used at the Trinity test and Nagasaki. Eventually Fermi and Szilrd's reactor work was folded into the Manhattan Project.

Fermi moved to Los Alamos in the later stages of the Manhattan Project to serve as a general consultant. His broad knowledge of many fields of physics was useful in solving problems that were of an interdisciplinary nature.

He became a naturalized citizen of the United States of America in 1944.

In his later years, Fermi did important work in particle physics, especially related to pions and muons. He was also known to be an inspiring teacher at the University of Chicago, and was known for his attention to detail, simplicity, and careful preparation for a lecture. Later, his lecture notes, especially those for quantum mechanics, nuclear physics, and thermodynamics, were transcribed into books which are still in print.

On November 28, 1954, Fermi died at the age of 53 of stomach cancer in Chicago, Illinois and was interred there in Oak Woods Cemetery. As Eugene Wigner wrote: "Ten days before Fermi had died he told me, 'I hope it won't take long.' He had reconciled himself perfectly to his fate".