Aharonov - Bohm Effect

The Aharonov–Bohm effect (for short: AB effect) is, quite generally, a non-local effect in which a physical object travels along a closed loop through a gauge fieldfree region and thereby undergoes a physical change. As such, the AB effect can be described as a holonomy. Its paradigmatic realization became widely known after Aharonov and Bohm’s 1959 paper – with forerunners by Weiss [1] and Ehrenberg and Siday [2]. Aharonov and Bohm [3] consider the following scenario: A split electron beam passes around a solenoid in which a magnetic field is confined. The region outside the solenoid is field-free, but nevertheless a shift in the interference pattern on a screen behind the solenoid can be observed upon alteration of the magnetic field. The schematic experimental setting can be grasped from the following figure: