Magnetic potential

In physics, the magnetic potential is a method of representing the magnetic field by using a potential value instead of the actual mathbf{B} vector field. There are two methods of relating the magnetic field to a potential field and they give rise to two possible types of magnetic potential.

Reality of potential fields

Since the magnetic field may be defined in terms of the magnetic vector potential field, which one of them is the "real" field? Presuming reality is what can be measured, it is possible to measure mathbf{B} using the Hall effect, while measuring mathbf{A} in a direct way is quite difficult.

Related Topics:
Magnetic field - Hall effect

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The interesting situation occurs that just outside a long solenoid, the value of mathbf{B} is quite small, whereas the value of mathbf{A} in the same region is comparatively large. The Aharonov-Bohm effect was first described as a thought experiment in 1956 and involves making an interference pattern using a stream of electrons passing through a double slit. Placing a magnetised iron whisker between the slits simulates the effect of a long, thin solenoid. In 1985 the experiment was constructed and it was observed that the interference pattern did shift as a result of the solenoid. This suggests that the mathbf{A} field can act in a region where mathbf{B} = 0 and thus we can conclude that mathbf{A} is the "real" field.

Related Topics:
Aharonov-Bohm effect - Interference pattern

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