Quantum Point Contact — Conductance Quantization

A quantum point contact is a narrow, gate-tunable constriction squeezed into a two-dimensional electron gas. This simulator visualizes electrons streaming through that constriction and plots the resulting conductance against gate voltage in real time. As the gates pinch the channel narrower, the number of transverse modes that can propagate ballistically drops one at a time, and the Landauer formula G = N·2e²/h produces the sharp staircase of plateaus first observed by van Wees et al. in 1988. Sweep the gate voltage to watch modes close and the conductance drop by exactly one quantum, G₀ = 2e²/h ≈ 77.5 μS, at a time.