Physics 541

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Physics 541
A quantum approach to condensed matter physics
Class 21
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Start with the kinetic energy
Define new number operators
creates electrons if u1 and holes if v1
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Now the potential energy
Make the nasty terms cancel!
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At zero temperature, no excitations, so all m 0
Make nasty terms cancel
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Now we need a simple model to work with
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Weak-coupling case
This explains why the superconducting transition
temperature is so small!
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So we can form the ground-state wavefunction as
Note that particle number is not conserved