Superconductivity
Superconductivity — the complete loss of electrical resistance below a critical temperature — is one of the most dramatic manifestations of macroscopic quantum coherence. The BCS theory of Bardeen, Cooper, and Schrieffer explains this through the formation of Cooper pairs: electrons with opposite momenta and spins bound by phonon-mediated attraction.
The Ginzburg-Landau phenomenological theory captures the macroscopic behavior near $T_c$, including the Meissner effect, flux quantization, and the distinction between type-I and type-II superconductors. The Josephson effect reveals macroscopic quantum tunneling of the superconducting condensate.
Chapters
1. Cooper Pairs
Cooper instability, pair wavefunction, phonon-mediated attraction, pair binding energy, and the Cooper problem.
2. BCS Theory
BCS ground state, gap equation, quasiparticle spectrum, thermodynamics, and the BCS-BEC crossover.
3. Ginzburg-Landau Theory
Order parameter, GL free energy, penetration depth, coherence length, and the Meissner effect.
4. Type-II Superconductors
Abrikosov vortex lattice, upper and lower critical fields, mixed state, and flux pinning.
5. Josephson Effect
DC and AC Josephson effects, Josephson junctions, SQUID, and macroscopic quantum tunneling.