COOPER PAIRS & BCS SUPERCONDUCTIVITY

Phonon-mediated pairing, energy gap, quasiparticle spectrum
BCS Theory (1957)

Gap equation (T=0):
Δ = 2ω_D exp(-1/λ)

Critical temperature:
k_BT_c = 1.134 ω_D exp(-1/λ)

Quasiparticle energy:
E_k = √(ξ_k² + Δ²)

Coherence length:
ξ₀ = ℏv_F / (π Δ)

Δ/Δ₀: —
State: —