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 experi ...

, 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 State of matter, phases, that arise from electromagnetic forces between atoms and elec ...

and

quantum mechanics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...

Early life

Foldy was born László Földi in kisszeben, Hungary (today's town of Sabinov, Slovakia), on October 26, 1919. In 1920, his family moved to the USA due to the invasion of Hungary around that time, and there he was known as Leslie Foldy.

Education

His high school education was in

Cleveland, Ohio Cleveland is a city in the U.S. state of Ohio and the county seat of Cuyahoga County, Ohio, Cuyahoga County. Located along the southern shore of Lake Erie, it is situated across the Canada–United States border, Canada–U.S. maritime border ...

, 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, high school, or senior school, is an institution that provides secondary education. Some secondary schools provide both ''lower secondary education'' (ages 11 to 14) and ''upper secondary education'' (ages 14 to 18), i.e., ...

, he picked up an interest in

physics Physics is the scientific study of matter, its Elementary particle, 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 whi ...

. 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 of Case Western Reserve University, a private research university in Cleveland, Ohio. It traces its roots to the 1880 founding of the Case School of Applied Science. The school was endowed ...

(now renamed to the ''Case Western Reserve University''), his senior thesis was on

crystal lattice In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystal, crystalline material. Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that ...

vibrations.

Research

He started his

PHD A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...

in 1945 at the

University of California The University of California (UC) is a public university, public Land-grant university, land-grant research university, research university system in the U.S. state of California. Headquartered in Oakland, California, Oakland, the system is co ...

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 to ...

, in

J. Robert Oppenheimer J. Robert Oppenheimer (born Julius Robert Oppenheimer ; April 22, 1904 – February 18, 1967) was an American theoretical physics, theoretical physicist who served as the director of the Manhattan Project's Los Alamos Laboratory during World ...

's group, and with Luis Alvarez and

David Bohm David Joseph Bohm (; 20 December 1917 – 27 October 1992) was an American scientist who has been described as one of the most significant Theoretical physics, theoretical physicists of the 20th centuryDavid Peat Who's Afraid of Schrödinger' ...

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

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

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

, 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 is a private university, private research university in Rochester, New York, United States. It was founded in 1850 and moved into its current campus, next to the Genesee River in 1930. With approximately 30,000 full ...

, Foldy and

Siegfried Adolf Wouthuysen Siegfried Adolf Wouthuysen (17 August 1916 – 14 July 1996) was a Dutch physicist who made contributions to quantum mechanics. He collaborated with Leslie Lawrance Foldy to develop the Foldy–Wouthuysen transformation, and with George B. Fiel ...

, working with Robert 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-1/2 massive particles, called "Dirac ...

. In 1950 at

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

, 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-1/2 particl ...

. 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 o ...

, 1953–54 *

Guggenheim Fellow Guggenheim Fellowships are grants that have been awarded annually since by the John Simon Guggenheim Memorial Foundation, endowed by the late Simon and Olga Hirsh Guggenheim. These awards are bestowed upon individuals who have demonstrated d ...

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

References

* * *

External links

*, Appendix G {{DEFAULTSORT:Foldy, Leslie Lawrance 1919 births 2001 deaths Condensed matter physicists American quantum physicists American 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