In quantum physics, what is the name of the two-slit experiment that reveals particle interference?

In quantum physics, the double-slit experiment reveals particle interference.

A source sends particles toward a barrier containing two narrow slits, with a detection screen behind it. When both slits are open and no which-path information is available, the accumulated detections form an interference pattern of bright and dark bands. This occurs even when particles are sent one at a time, showing that the pattern is built from individual quantum events.

The experiment is associated with Thomas Young’s early-nineteenth-century work using light, which supported wave theories. Quantum versions have been performed with photons, electrons, neutrons, atoms, and larger molecules. The type of particle does not remove the wave-like interference effect.

If an apparatus determines which slit the particle used, the interference pattern disappears or is reduced. This is often called wave–particle duality, but the experiment does not show a tiny classical object literally changing identity. It demonstrates that quantum amplitudes and measurement information determine the observed distribution.