Instead of a 3D slab, this view plots the same BCS physics as two 2D scientific diagrams. The top panel is a phase diagram: the gap Δ(T)/Δ(0) (orange) and condensate fraction nₛ/n (cyan) traced as curves across the whole temperature range, with a marker showing exactly where the current T sits on each curve.
Δ(T) = Δ(0) · tanh( 1.74 · √(T꜀/T − 1) ) for T < T꜀
nₛ/n = 1 − (T/T꜀)⁴
The bottom panel is a depth cross-section: horizontal position = depth x into the material from the surface (left edge), the filled curve and colour intensity show the Meissner-expelled field B(x), and the scattered dots below are a 2D density map of Cooper pairs (cyan) vs thermally-excited normal quasiparticles (grey) — their ratio tracks nₛ/n live, exactly as in the 3D version, just rendered as a flat statistical scatter instead of populated 3D space.
B(x) = B₀ · exp(−x / λ(T))
λ(T) = λ(0) / √(nₛ/n) = λ(0) / √(1 − (T/T꜀)⁴)
As T → T꜀, nₛ/n → 0 and λ(T) → ∞ — the field curve flattens out (no more decay) and the scatter turns fully grey.
- Material — swaps Δ(0), T꜀ and λ(0) for real elemental superconductors (BCS-derived tabulated gap values).
- Temperature slider — moves the marker along both phase-diagram curves and reshapes the field-decay curve below.
- Applied field — scales the field curve's height at the surface (x = 0); it does not change λ(T) itself.
- Slab depth shown — sets how many nanometres of depth the bottom panel's x-axis spans.
Real-world relevance: this is the physics behind MRI-magnet and particle-accelerator superconducting coils (Nb-Ti, Nb₃Sn) — the coil must stay well below T꜀ or the Meissner screening collapses and the field (and the persistent current) dumps.