Why bound currents cannot be detected in experiment? In today's group meeting about anomalous Nernst effect, I learned that bound currents cannot be detected in experiment. Why?
 A: While finding the vector potential due to piece of magnetized material with magnetization  M ,it is turn out that it is same as potential produced by a volume current and a surface current called bound current. Physical interpretation for them that in uniform magnetized material there tiny current loops which produces dipole moment. 
The net effect of these loop is a surface current.
It is clear that it's just an analogy too understand the net effect of those tiny loop.If you try to measure the surface bound current ,you will unable as there only tiny current loops in reality.
A: I know the answer. It's in the article Cooper, N. R., B. I. Halperin, and I. M. Ruzin, 1997, Phys. Rev.B 55, 2344.  Bound currents do not make any contribution to the net current flows that are measured by conventional transport experiments. Specifically, consider any closed curve C that encircles the sample but is exterior to it, and let S be a surface spanning this contour. The total magnetization currents crossing the surface must be zero, by Stokes’s theorem, and the total currents IS crossing the surface are obtained by considering the transport currents alone.

