Leon Cooper

Cooper with his wife, Kay Allard, in 1972

Leon N Cooper (February 28, 1930 – October 23, 2024) was an American physicist and Nobel Prize laureate who, with John Bardeen and John Robert Schrieffer, developed the BCS theory of superconductivity. He is also the namesake of the Cooper pair and co-developer of the BCM theory of synaptic plasticity.

Quotes

• Consider a pair of electrons which interact above a quiescent Fermi sphere with an interaction of the kind that might be expected due to the phonon and the screened Coulomb fields. If there is a net attraction between the electrons, it turns out that they can form a bound state, though their total energy is larger than zero. The properties of a noninteracting system of such bound pairs are very suggestive of those which could produce a superconducting state.
  • (15 November 1956)"Bound Electron Pairs in a Degenerate Fermi Gas". Physical Review 104 (4): 1189–1190. DOI:10.1103/PhysRev.104.1189.

• Relativity, from one viewpoint the beginning of twentieth-century physics, is from another the capstone of classical physics, the final and most elegant variation of the world view initiated by Galileo and Newton. In a sense, after Einstein, classical physics, just as after Mozart classical music, could go no further.
  • An Introduction to the Meaning and Structure of Physics. Harper & Row. 1970. p. 301. 

• The fundamental qualitative difference between the superconducting and normal ground state wave function is produced when the large degeneracy of the single particle electron levels in the normal state is removed. If we visualize the Hamiltonian matrix which results from an attractive two-body interaction in the basis of normal metal configurations, we find in this enormous matrix, sub-matrices in which all single-particle states except for one pair of electrons remain unchanged. These two electrons can scatter via the electron-electron interaction to all states of the same total momentum. We may envisage the pair wending its way (so to speak) over all states unoccupied by other electrons.
  • Microscopic Quantum Interference Effects in the Theory of Superconductivity, Nobel Lecture, December 11, 1972 by Leon N. Cooper. nobelprize.org.

• The long and imposing list of physicists (among them Bohr, Heisenberg and Feynman) who had tried or were trying their hand at superconductivity should have given me pause. Even Einstein, in 1922 — before the quantum theory of metals was in place — had attempted to construct a theory of superconductivity. Fortunately, I was unaware of these many unsuccessful attempts. So when John invited me to join him (he, somehow, neglected to mention these previous efforts), I decided to take the plunge.
  • "Remembrance of Superconductivity Past by Leon N. Cooper". BCS: 50 Years. World Scientific Publishing Co. 2011. pp. 3–19. ISBN 9789814304658.  (quote from p. 4)

• How do we get emotions and feelings out of neurons which, presumably, don't have emotions and feelings?
  • On Consciousness: Leon Cooper. Brown University Department of Physics, YouTube (22 June 2017).