Llewellyn Thomas
Llwellyn Hilleth Thomas ( born October 31, 1903 in London, † April 20, 1992 in Raleigh (North Carolina)), usually simply quoted LH Thomas, was a British theoretical physicist and applied mathematician.
Life and work
Thomas studied at the University of Cambridge ( Trinity College), where he heard Mathematics at Bromwich and John Edensor Littlewood and physics among others Arthur Eddington and Ralph Fowler. He earned his bachelor 's degree in 1924 and master's degree in 1928 and received his doctorate in 1927 in Cambridge.
1925 and 1926 he lived in Copenhagen and met Yoshio Nishina and Friedrich Hund. Thomas was from 1929 to 1943 ( and 1945 /6) at the Ohio State University and during the Second World War at Aberdeen Proving Ground U.S. Army ( the ballistic research center). From 1945 he was at the Watson Scientific Computing Laboratory (sponsored by IBM) at Columbia University, where he worked on the programming of computer systems with Wallace John Eckert. In 1946 he was at the Columbia University professor of physics but also lectured eg via numerics of differential equations. In 1963, he was IBM Fellow. In 1968, he was at IBM and Columbia University 's retirement and went to the North Carolina State University. In 1976, he retired.
Thomas is known for the Thomas precession of the electron in the atom (1926) and the Thomas-Fermi model (1927 ) with Enrico Fermi, a statistical theory of the atom. The Thomas precession is a relativistic correction to the spin-orbit interaction of an electron in an atom (or a gyroscope in orbit ) It provided a hitherto missing factor ½ in the fine -structure splitting of the hydrogen atom.
In Watson Computer Laboratory at Columbia University, he invented the magnetic core memory before the An Wang. He was said to be responsible for the format of the instructions of the IBM used on laboratory NORC ( Naval Ordnance Research Computer ) with three addresses.
1954 brought Thomas into the headlines of Time magazine with an argument against the propagated by Wernher von Braun to promote the use of space satellites in earth orbit for military purposes. Thomas pointed out that it would be far more cost effective to bring in orbit a bomb explosion to turn off the satellite.
From 1958 he was a member of the National Academy of Sciences.
Thomas worked mostly for himself and had few students, including Leonard ship.
Thomas developed in 1938 a method of sector division of the Zyklotronmagneten to solve the Defokussierungsproblemen cyclotrons at higher energies, where does the relativistic mass increase noticeable ( Thomas cyclotron ). It was, however, difficult to implement and ahead of its time and was only in 1950 in Berkeley realized Reginald John Richardson and others.