Andreev Bound States — Short Josephson Junction

JUNCTION PARAMETERS

↑ drag φ to animate ABS

ABS ENERGIES

E₊(φ):
E₋(φ):
Josephson current:
Critical current I_c:

ABS THEORY

Short junction (L≪ξ):
E±(φ) = ±Δ√(1−τ·sin²(φ/2))

ABS carry supercurrent:
I(φ) = (eΔ/ħ) Σ_n τ_n sin(φ)/(2E_n)

For perfect τ=1:
E±(φ) = ±Δ|cos(φ/2)|
I_c = eΔ/ħ (maximum)

Andreev reflection: e⁻ → hole
at NS interface (retroreflection)