Leon Cooper
(1930 - )
Leon Neil Cooper was born on February 28, 1930,
in New York. He studied at Columbia Univeristy (A.B. 1951; A.M. 1953;
Ph.D. 1954). From 1954 to 1955, he became a member of the Institute
for Advanced Study; from 1955-1957, research associate of Illinois;
from 1957-1958, an assistant professor at the Ohio State University.
Since 1958, Cooper has been teaching at Brown University. Currently,
Cooper is the Thomas J. Watson, Sr. Professor of Science at Brown.
He was awarded the 1972 Nobel
Prize for Physics, along with John Bardeen and John Robert Schrieffer,
for his role in developing the BCS theory (named for their initials)
of superconductivity. Also the concept of Cooper electron pairs was
named after him.
Besides receiving the Nobel Prize, Cooper was awarded
the Comstock Prize in 1968, along with J.R. Schrieffer, from the National
Academy of Sciences. He is also a member of several distinguished societies
including the American Academy of Arts and Sciences; American Philosophical
Society; and the National Academy of Sciences.
The following press release from the Royal Swedish
Academy of Sciences describes Cooper’s work:
“The phenomenon of superconductivity was discovered
by the Dutch physicist Kamerling Onnes already in 1911. Already his
first measurements indicated that one had found a fundamentally new
state of matter. The term superconductivity refers to the complete
disappearance of the electrical resistance. Many remarkable properties
were discovered in the following decades. However, the central problem,
the question about the underlying mechanism for superconductivity,
remained a mystery up to the late 50’s. The difference in energy
between the superconducting and the normal state in a metal is extremely
small in comparison with all typical energies in a metal and therefore
many different mechanisms might a priori be possible. A significant
step forward was taken around 1950 when it was found theoretically
and experimentally that the mechanism for superconductivity had to
do with the coupling of electrons to the vibrations of the crystal
lattice. Starting from this mechanism, Bardeen, Cooper and Schrieffer
developed in 1957 a theory of superconductivity, which gave a complete
theoretical explanation of the phenomenon.
The new theory demonstrated that the interaction
between the electrons and the lattice leads to the formation of bound
pairs of electrons, which are often called Cooper-pairs. The different
pairs are strongly coupled to each other which leads to a complex
collective pattern in which a considerable fraction of the total number
of conduction electrons are coupled together to form the superconducting
state. Because of the characteristic coupling between all the electrons,
one cannot break up a single pair of electrons without perturbing
also all the others and this requires an amount of energy which must
exceed a critical value. Many of the remarkable properties of superconductors
can be understood qualitatively from the structure of this correlated
many-electron state.
The theory developed by Bardeen, Cooper and Schrieffer
together with extensions and refinements of the theory, which were
developed by many authors soon after the key discovery, was indeed
very successful in explaining in considerable detail the properties
of superconductors. The theory also predicted new effects and it stimulated
an intensive activity in theoretical and experimental research, which
opened up new areas for research. One may as examples mention the
use of the quantum mechanical tunnel phenomena to study superconductors,
the discovery of magnetic flux quantization and the remarkable Josephson
effects. These more recent developments are intimately connected with
the fundamental theory of superconductivity and have confirmed in
a striking way the validity of the theoretical concepts and ideas
developed by Bardeen, Cooper and Schrieffer.”
Sources: Nobel
Prize; Press
Release by Nobel Prize Committee; Wikipedia |