Aharonov–Bohm effect
The Aharonov–Bohm effect, sometimes called the Ehrenberg–Siday–Aharonov–Bohm effect, is a quantum-mechanical phenomenon in which an electrically charged particle is affected by an electromagnetic potential ( φ {\displaystyle \varphi } , A {\displaystyle \mathbf {A} } ), despite being confined to a region in which both the magnetic field B {\displaystyle \mathbf {B} } and electric field E {\displaystyle \mathbf {E} } are zero. The underlying mechanism is the coupling of the electromagnetic potential with the complex phase of a charged particle's wave function, and the Aharonov–Bohm effect is accordingly illustrated by interference experiments.