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Paul Adrien Maurice Dirac

Paul Adrien Maurice Dirac

[dih-rak]
Dirac, Paul Adrien Maurice, 1902-84, English physicist. He was educated at the Univ. of Bristol and St. John's College, Cambridge, and became professor of mathematics at Cambridge in 1932. In 1928, Dirac published a version of quantum mechanics that took into account the theory of relativity (see quantum theory). One consequence of his theory was the prediction of negative energy states for the electron, implying the existence of an antiparticle to the electron; this antiparticle, the positron, was discovered in 1932 by C. D. Anderson. Dirac's equation for the motion of a particle is a relativistic modification of the Schrödinger wave equation, the basic equation of quantum mechanics. For their work Dirac and Erwin Schrödinger shared the 1933 Nobel Prize in Physics. Dirac also received the Copley Medal of the Royal Society in 1952 for this and other contributions to the quantum theory, including his formulation (with Enrico Fermi) of the Fermi-Dirac statistics and his work on the quantum theory of electromagnetic radiation. He wrote The Principles of Quantum Mechanics (1930, 4th ed. 1958).

See biographies by H. Kragh (1990) and G. Farmelo (2009).

(born Aug. 8, 1902, Bristol, Gloucestershire, Eng.—died Oct. 20, 1984, Tallahassee, Fla., U.S.) English mathematician and theoretical physicist. His first major contribution (1925–26) was a general and logically simple form of quantum mechanics. About the same time, he developed ideas of Enrico Fermi, which led to the Fermi-Dirac statistics. He then applied Albert Einstein's special theory of relativity to the quantum mechanics of the electron and showed that the electron must have spin of 12. Dirac's theory also revealed new states later identified with the positron. He shared the 1933 Nobel Prize for Physics with Erwin Schrödinger. In 1932 Dirac was appointed Lucasian Professor of Mathematics at the University of Cambridge, a chair once occupied by Isaac Newton. Dirac retired from Cambridge in 1969 and held a professorship at Florida State University from 1971 until his death.

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Adrien-Maurice, 3rd duc de Noailles (September 29, 1678June 24, 1766) was a French aristocrat and soldier.

Biography

Son of Anne-Jules, 2nd duc de Noailles, he inherited the title duc de Noailles on his father's death in 1708.

He fought in the War of the Spanish Succession (1710–1713) and was president of the Finance Council from 1715 to 1718. He distinguished himself in the War of the Polish Succession (1733–1738) and was made a marshal of France in 1734, becoming dean of the marshals in 1748. He served in the War of the Austrian Succession and was appointed to command the French forces in March 1743. He was defeated at the Battle of Dettingen in June 1743, but successfully drove the Austrians out of Alsace-Lorraine the following year, although he missed an opportunity to seriously damage the Austrian army as it was crossing the Rhine. He was Foreign Minister from April to November 1744, and regarded Great Britain as a greater enemy of France than Austria. He later acted in a diplomatic capacity and had substantial influence over the course of foreign policy.

In 1698, as comte d'Ayen, he married Françoise Charlotte Amable d'Aubigny, niece and beneficiary of the marquise de Maintenon, and by her had six children, 4 daughters and 2 sons.
His two sons Louis, 4th duc de Noailles, and Philippe, duc de Mouchy, also went on to become marshals of France.

The duc de Noailles was made a knight of the Order of the Golden Fleece in 1702, a Grandee of Spain in 1711, and a Knight of the Order of Saint-Esprit in 1724.

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