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Superconductivity and BCS theory
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Cooper pairs carry current without resistance.
Bardeen–Cooper–Schrieffer theory: electrons form Cooper pairs through lattice vibrations, condense into a coherent state with an energy gap, and flow without resistance. High-temperature superconductors are not fully understood.
Aluminium's T_c = 1.2 K.
Pairs are bosons, not individual electrons.
In more detail
Superconductivity is the state of zero resistance and expulsion of magnetic fields below a critical temperature. The BCS theory explains it by electron pairs, called Cooper pairs, forming a coherent condensate.
Real-world uses
- Superconducting magnets are used in MRI scanners and accelerators.
- Superconducting qubits form the basis of many quantum computers.
- Engineers and physicists use superconductors in MRI scanners and maglev trains, which depend on Cooper pairs carrying current without resistance.
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Frequently asked questions
What are Cooper pairs?
Pairs of electrons that bind through lattice vibrations and move without scattering.
Why was BCS important?
It explained superconductivity in conventional materials, earning a Nobel Prize in 1972.
What is a Cooper pair?
Two electrons bound together by lattice vibrations, which behave as a single boson and condense into a superconducting state.