- Physics. a general quantum theory of superconductivity that describes many properties of superconducting materials. Also called Bardeen-Cooper-Schrieffer theory.[after U.S. physicists J. BARDEEN, Leon N. Cooper (born 1930), and John R. Schrieffer (born 1929)]
* * *Comprehensive theory that explains the behaviour of superconducting materials.It was developed in 1957 by John Bardeen, Leon Cooper, and J. Robert Schrieffer (b. 1931), whose surname initials provide its name. Cooper discovered that electrons in a superconductor are grouped in pairs (Cooper pairs) and that the motions of all the pairs within a single superconductor constitute a system that functions as a single entity. An electric voltage applied to the superconductor causes all Cooper pairs to move, forming an electric current. When the voltage is removed, the current continues to flow because the pairs encounter no opposition. See also superconductivity.
* * *▪ physicsin physics, a comprehensive theory developed in 1957 by the American physicists John Bardeen (Bardeen, John), Leon N. Cooper (Cooper, Leon N.), and John R. Schrieffer (Schrieffer, John Robert) (their surname initials providing the designation BCS) to explain the behaviour of superconducting materials. Superconductors abruptly lose all resistance to the flow of an electric current when they are cooled to temperatures near absolute zero.Cooper had discovered that electrons in a superconductor are grouped in pairs, now called Cooper pairs, and that the motions of all of the Cooper pairs within a single superconductor are correlated; they constitute a system that functions as a single entity. Application of an electrical voltage to the superconductor causes all Cooper pairs to move, constituting a current. When the voltage is removed, current continues to flow indefinitely because the pairs encounter no opposition. For the current to stop, all of the Cooper pairs would have to be halted at the same time, a very unlikely occurrence. As a superconductor is warmed, its Cooper pairs separate into individual electrons, and the material becomes normal, or nonsuperconducting.Many other aspects of the behaviour of superconductors are explained by the BCS theory. The theory supplies a means by which the energy required to separate the Cooper pairs into their individual electrons can be measured experimentally. The BCS theory also explains the isotope effect, in which the temperature at which superconductivity appears is reduced if heavier atoms of the elements making up the material are introduced.
* * *
Look at other dictionaries:
BCS theory — is a microscopic theory of superconductivity, proposed by Bardeen, Cooper, and Schrieffer. It describes superconductivity as a microscopic effect caused by Bose condensation of pairs of electrons.HistoryBCS theory was developed in 1957 by John… … Wikipedia
BCS theory — Physics. a general quantum theory of superconductivity that describes many properties of superconducting materials. Also called Bardeen Cooper Schrieffer theory. [after U.S. physicists J. BARDEEN, Leon N. Cooper (born 1930), and John R.… … Useful english dictionary
BCS — may refer to:American football* Bowl Championship Series, a system that selects matchups for college football bowl games * BCS National Championship Game, the final bowl game of the annual Bowl Championship Series * BCS conference, the six major… … Wikipedia
theory — /thee euh ree, thear ee/, n., pl. theories. 1. a coherent group of general propositions used as principles of explanation for a class of phenomena: Einstein s theory of relativity. 2. a proposed explanation whose status is still conjectural, in… … Universalium
BCS-Theorie — Die BCS Theorie ist eine Vielteilchentheorie zur Erklärung der Supraleitung in Metallen. Die BCS Theorie wurde 1957 von John Bardeen, Leon N. Cooper und John R. Schrieffer entwickelt. Der Name leitet sich aus den Anfangsbuchstaben der Nachnamen… … Deutsch Wikipedia
Effective field theory — In physics, an effective field theory is an approximate theory (usually a quantum field theory) that includes appropriate degrees of freedom to describe physical phenomena occurring at a chosen length scale, while ignoring substructure and… … Wikipedia
Quantum field theory — In quantum field theory (QFT) the forces between particles are mediated by other particles. For instance, the electromagnetic force between two electrons is caused by an exchange of photons. But quantum field theory applies to all fundamental… … Wikipedia
Mattis–Bardeen theory — The Mattis–Bardeen theory is a possible explanation of a phenomenon observed in superconductors. Contents 1 Introduction 2 The response to the electromagnetic wave 3 Use in Optical Study 4 Referen … Wikipedia
Microscopic theory — A microscopic theory is one that contains an explanation at the atomic or subatomic level in contrast to a higher level or classical macroscopic or phenomenological theory. eg in superconductivity BCS theory is a microscopic theory. References… … Wikipedia
Werthamer–Helfand–Hohenberg theory — This theory was proposed in 1966 [ N. R. Werthamer, E. Helfand, P. C. Hohenberg: Phys. Rev. 147 (1966) 295 ] to go beyond BCS theory of superconductivity and it provides predictions of upper critical field (Hc2) in type II superconductors… … Wikipedia