Josephson Junction Fluxon

The long Josephson junction obeys the sine-Gordon equation: φₜₜ − φₓₓ + sin(φ) = γ − αφₜ. A fluxon (kink soliton) carries one flux quantum Φ₀. Shapiro steps appear under AC bias.

DC Bias γ 0.10 Damping α 0.10 AC Amplitude 0.00

V = ⟨∂φ/∂t⟩ = 0.00 | Shapiro step: n·ω/2π