Aharonov-Bohm Effect

What you are seeing: a solenoid (orange dot) sits between the two paths of a double-slit interferometer. Even though $\mathbf B = 0$ outside the solenoid, the electron wavefunction picks up a phase $\delta \phi = e \Phi / \hbar$ around the closed loop, shifting the fringes. The shift is exactly one fringe per flux quantum $\Phi_0 = h/e$ .

Figure 1. Two-slit fringes shifted by enclosed flux.

Φ / Φ₀0.00

WHAT TO TRY

On load the flux ramps on its own: watch the whole fringe pattern slide sideways while the solenoid stays dark (B = 0 on the electron paths).
Drag Φ/Φ₀ to take manual control. At every integer the pattern returns to itself; the fringe-shift plot shows the shift tracking Φ/Φ₀ one-for-one.
Follow the pink central-fringe marker on the detector: it is displaced purely by the vector potential, with no force ever acting on the electron.