046
Quantum tunnelling
A barrier the particle cannot climb, and a chance of being found beyond it.
Field
Detail
Study
046
Chapter
Quantum mechanics
Equation
E < V₀, ψ(x) ∝ e^(−κx), T ≈ 0.347
What moves
the barrier width a; the stream of electrons
Structure
Film
Colour means
position through the barrier
Posted
Electrons stream towards a thin glass wall they do not have the energy to cross. Most turn back. Inside the wall the wave does not stop; it shrinks, and a smaller wave continues on the far side. Roughly one in three is found beyond the barrier. The wall is then thinned and thickened, and the fraction that gets through rises and falls with it. The decay inside the wall is exponential, set by κ.