Editing Enrico Fermi (section)

== Postwar work ==
Fermi became the Charles H. Swift Distinguished Professor of Physics at the University of Chicago on 1 July 1945,{{sfn|Segrè|1970|p=157}} although he did not depart the Los Alamos Laboratory with his family until 31 December 1945.{{sfn|Segrè|1970|p=167}} He was elected a member of the [[US National Academy of Sciences]] in 1945.<ref name="NAS">{{cite web| url = http://www.nasonline.org/member-directory/deceased-members/20001146.html| title="Enrico Fermi" on NASOnline.org| access-date = 18 February 2016| archive-date = 25 February 2016| archive-url = https://web.archive.org/web/20160225055710/http://www.nasonline.org/member-directory/deceased-members/20001146.html| url-status = live}}</ref> The Metallurgical Laboratory became the [[Argonne National Laboratory]] on 1 July 1946, the first of the [[United States Department of Energy National Laboratories|national laboratories]] established by the Manhattan Project.{{sfn|Holl|Hewlett|Harris|1997|pp=xix–xx}} The short distance between Chicago and Argonne allowed Fermi to work at both places. At Argonne he continued experimental physics, investigating [[neutron scattering]] with [[Leona Marshall]].{{sfn|Segrè|1970|p=171}} He also discussed theoretical physics with [[Maria Mayer]], helping her develop insights into [[spin–orbit coupling]] that would lead to her receiving the Nobel Prize.{{sfn|Segrè|1970|p=172}}

The Manhattan Project was replaced by the [[United States Atomic Energy Commission|Atomic Energy Commission]] (AEC) on 1 January 1947.{{sfn|Hewlett|Anderson|1962|p=643}} Fermi served on the AEC General Advisory Committee, an influential scientific committee chaired by Robert Oppenheimer.{{sfn|Hewlett|Anderson|1962|p=648}} He also liked to spend a few weeks each year at the Los Alamos National Laboratory,{{sfn|Segrè|1970|p=175}} where he collaborated with [[Nicholas Metropolis]],{{sfn|Segrè|1970|p=179}} and with [[John von Neumann]] on [[Rayleigh–Taylor instability]], the science of what occurs at the border between two fluids of different densities.{{sfn|Bonolis|2001|p=381}}

[[File:Laura and Enrico Fermi 1954.jpg|thumb|left|[[Laura Fermi|Laura]] and Enrico Fermi at the [[Institute for Nuclear Studies]], Los Alamos, 1954]]
After the detonation of the first Soviet [[fission bomb]] in August 1949, Fermi, along with Isidor Rabi, wrote a strongly worded report for the committee, opposing the development of a hydrogen bomb on moral and technical grounds.{{sfn|Hewlett|Duncan|1969|pp=380–385}} Nonetheless, Fermi continued to participate in work on the hydrogen bomb at Los Alamos as a consultant. Along with [[Stanislaw Ulam]], he calculated that not only would the amount of [[tritium]] needed for Teller's model of a thermonuclear weapon be prohibitive, but a [[fusion reaction]] could still not be assured to propagate even with this large quantity of tritium.{{sfn|Hewlett|Duncan|1969|pp=527–530}} Fermi was among the scientists who testified on Oppenheimer's behalf at the [[Oppenheimer security hearing]] in 1954 that resulted in the denial of Oppenheimer's security clearance.{{sfn|Cooper|1999|pp=102–103}}

In his later years, Fermi continued teaching at the University of Chicago, where he was a founder of what later became the [[Enrico Fermi Institute]]. His PhD students in the postwar period included [[Owen Chamberlain]], [[Geoffrey Chew]], [[Jerome Isaac Friedman|Jerome Friedman]], [[Marvin Goldberger]], [[Tsung-Dao Lee]], [[Arthur Rosenfeld]] and [[Sam Treiman]].<ref name="mathgene">{{MathGenealogy|id=14167}}</ref><ref name="Nobel">{{Nobelprize}} including the Nobel Lecture, 12 December 1938 ''Artificial Radioactivity Produced by Neutron Bombardment''</ref> [[Jack Steinberger]] was a graduate student, and [[Mildred Dresselhaus]] was highly influenced by Fermi during the year she overlapped with him as a PhD student.<ref>{{cite web |url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1988/steinberger-bio.html |access-date=15 August 2013 |title=Jack Steinberger&nbsp;– Biographical |publisher=Nobel Foundation |archive-date=4 October 2013 |archive-url=https://web.archive.org/web/20131004230100/http://www.nobelprize.org/nobel_prizes/physics/laureates/1988/steinberger-bio.html |url-status=live }}</ref><ref name="Cornish">{{cite news |last1=Cornish |first1=Audie |title='Queen Of Carbon' Among Medal Of Freedom Honorees |url=https://www.npr.org/2014/11/24/366379355/queen-of-carbon-among-medal-of-freedom-honorees |access-date=30 September 2018 |work=All Things Considered |publisher=NPR |date=24 November 2014 |archive-date=30 September 2018 |archive-url=https://web.archive.org/web/20180930115640/https://www.npr.org/2014/11/24/366379355/queen-of-carbon-among-medal-of-freedom-honorees |url-status=live }}</ref> Fermi conducted important research in particle physics, especially related to [[pion]]s and [[muon]]s. He made the first predictions of pion-[[nucleon]] resonance,{{sfn|Segrè|1970|p=179}} relying on [[statistical methods]], since he reasoned that exact answers were not required when the theory was wrong anyway.{{sfn|Bonolis|2001|pp=374–379}} In a paper coauthored with [[Chen Ning Yang]], he speculated that pions might actually be composite particles.<ref>{{Cite journal | last1 = Fermi | first1 = E. | last2 = Yang | first2 = C. | doi = 10.1103/PhysRev.76.1739 | title = Are Mesons Elementary Particles? | journal = Physical Review | volume = 76 | issue = 12 | page = 1739 | year = 1949 |bibcode = 1949PhRv...76.1739F }}</ref> The idea was elaborated by [[Shoichi Sakata]]. It has since been supplanted by the [[quark model]], in which the pion is made up of quarks, which completed Fermi's model, and vindicated his approach.{{sfn|Jacob|Maiani|2001|pp=254–258}}

Fermi wrote a paper "On the Origin of [[cosmic radiation|Cosmic Radiation]]" in which he proposed that cosmic rays arose through material being accelerated by magnetic fields in interstellar space, which led to a difference of opinion with Teller.{{sfn|Bonolis|2001|pp=374–379}} Fermi examined the issues surrounding magnetic fields in the arms of a [[spiral galaxy]].{{sfn|Bonolis|2001|p=386}} He mused about what is now referred to as the "[[Fermi paradox]]": the contradiction between the presumed probability of the existence of extraterrestrial life and the fact that contact has not been made.{{sfn|Jones|1985a|pp=1–3}}

[[File:Enrico fermi tomb2.jpg|right|thumb|upright|Fermi's grave at [[Oak Woods Cemetery]], Chicago, near the university]]
Toward the end of his life, Fermi questioned his faith in society at large to make wise choices about nuclear technology. He said:

{{quote|Some of you may ask, what is the good of working so hard merely to collect a few facts which will bring no pleasure except to a few long-haired professors who love to collect such things and will be of no use to anybody because only few specialists at best will be able to understand them? In answer to such question[s] I may venture a fairly safe prediction.

The history of science and technology has consistently taught us that scientific advances in basic understanding have sooner or later led to technical and industrial applications that have revolutionized our way of life. It seems to me improbable that this effort to get at the structure of matter should be an exception to this rule. What is less certain, and what we all fervently hope, is that man will soon grow sufficiently adult to make good use of the powers that he acquires over nature.{{sfn|Fermi|2004|p=142}}
}}