Leslie Lawrance Foldy (1919–2001) was a

theoretical physicist Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experimen ...

, who made contributions to

condensed matter physics Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter, especially the solid and liquid phases which arise from electromagnetic forces between atoms. More generally, the sub ...

and

quantum mechanics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, ...

Early life

Foldy was born in Sabinov, Czechoslovakia, on October 26, 1919. His parents were of Hungarian origin, and named their son László Földi. In 1920, the family moved to the USA due to the invasions of Czechoslovakia by Hungary around that time, and there he was known as Leslie Foldy.

Education

His high school education was in

Cleveland, Ohio Cleveland ( ), officially the City of Cleveland, is a city in the U.S. state of Ohio and the county seat of Cuyahoga County. Located in the northeastern part of the state, it is situated along the southern shore of Lake Erie, across the U.S. ...

, and at that time he called his middle name "Lawrance", upon noticing he hadn't a middle name while the other students had. While at

high school A secondary school describes an institution that provides secondary education and also usually includes the building where this takes place. Some secondary schools provide both '' lower secondary education'' (ages 11 to 14) and ''upper seconda ...

, he picked up an interest in

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

. In 1941, Foldy graduated with a B.S. degree in physics from the

Case School of Applied Science The Case School of Engineering is the engineering school at Case Western Reserve University in Cleveland, Ohio, USA. It traces its roots to the 1880 founding of the Case School of Applied Science. It became the Case Institute of Technology in 1947 ...

(now renamed to the ''Case School of Engineering''), his senior thesis was on

crystal lattice In geometry and crystallography, a Bravais lattice, named after , is an infinite array of discrete points generated by a set of discrete translation operations described in three dimensional space by : \mathbf = n_1 \mathbf_1 + n_2 \mathbf_2 + n ...

vibrations.

Research

He started his

PHD PHD or PhD may refer to: * Doctor of Philosophy (PhD), an academic qualification Entertainment * '' PhD: Phantasy Degree'', a Korean comic series * ''Piled Higher and Deeper'', a web comic * Ph.D. (band), a 1980s British group ** Ph.D. (Ph.D. albu ...

in 1945 at the

University of California The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, Irvine, Los Angeles, Merced, Riverside, San Diego, San Francisco, ...

Berkeley Berkeley most often refers to: *Berkeley, California, a city in the United States **University of California, Berkeley, a public university in Berkeley, California * George Berkeley (1685–1753), Anglo-Irish philosopher Berkeley may also refer ...

, in

J. Robert Oppenheimer J. Robert Oppenheimer (; April 22, 1904 – February 18, 1967) was an American theoretical physicist. A professor of physics at the University of California, Berkeley, Oppenheimer was the wartime head of the Los Alamos Laboratory and is often ...

's group, and with Luis Alvarez and

David Bohm David Joseph Bohm (; 20 December 1917 – 27 October 1992) was an American-Brazilian-British scientist who has been described as one of the most significant theoretical physicists of the 20th centuryPeat 1997, pp. 316-317 and who contributed u ...

, until 1947. In 1948 he completed his doctoral degree at the

Institute for Advanced Study The Institute for Advanced Study (IAS), located in Princeton, New Jersey, in the United States, is an independent center for theoretical research and intellectual inquiry. It has served as the academic home of internationally preeminent scholar ...

Princeton Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the nine ...

, and later returned to the Case Institute of Technology as an assistant professor of physics. In 1949 at the

University of Rochester The University of Rochester (U of R, UR, or U of Rochester) is a private research university in Rochester, New York. The university grants undergraduate and graduate degrees, including doctoral and professional degrees. The University of Roc ...

, Foldy and

Siegfried Adolf Wouthuysen Siegfried Adolf Wouthuysen (17 August 1916 – 14 July 1996) was a Dutch physicist who made contributions to quantum mechanics. Early life Wouthuysen was born in Amsterdam in 1916. He obtained his bachelor's degree in Chemistry at Ghent Universi ...

, working with

Robert Marshak Robert Eugene Marshak (October 11, 1916 – December 23, 1992) was an American physicist, educator, and eighth president of the City College of New York. Biography Marshak was born in the Bronx, New York City. His parents, Harry and Rose Marshak ...

, wrote a preprint on the nonrelativistic limit of the

Dirac equation In particle physics, the Dirac equation is a relativistic wave equation derived by British physicist Paul Dirac in 1928. In its free form, or including electromagnetic interactions, it describes all spin- massive particles, called "Dirac part ...

. In 1950 at

Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and the ...

, their work was criticized as erroneous, motivating Foldy and Wouthuysen to make their calculations clear and efficient. A transformation forming part of their calculations is now called the

Foldy–Wouthuysen transformation The Foldy–Wouthuysen transformation was historically significant and was formulated by Leslie Lawrance Foldy and Siegfried Adolf Wouthuysen in 1949 to understand the nonrelativistic limit of the Dirac equation, the equation for spin-½ partic ...

. Positions he held at the Institute for Advanced Study include: *

Fulbright Fellow The Fulbright Program, including the Fulbright–Hays Program, is one of several United States Cultural Exchange Programs with the goal of improving intercultural relations, cultural diplomacy, and intercultural competence between the people of ...

, 1953–54 *

Guggenheim Fellow Guggenheim Fellowships are grants that have been awarded annually since by the John Simon Guggenheim Memorial Foundation to those "who have demonstrated exceptional capacity for productive scholarship or exceptional creative ability in the ar ...

, 1953–54 *NSF Sr Postdoc Fellow, 1963–64

References

* * *

External links

*, Appendix G {{DEFAULTSORT:Foldy, Leslie Lawrance 1919 births 2001 deaths Condensed matter physicists Quantum mechanics Theoretical physicists Fellows of the American Physical Society Czechoslovak emigrants to the United States Case Western Reserve University alumni University of California, Berkeley alumni University of Rochester faculty