The Boundary-Value Problem, Ch The vector potential and the magnetostatic boundary-value problem
Problem
For the uniform field B=B0z^, A1=B0xy^ is a valid vector potential. Someone claims that A2=21B0(xy^+yx^) is obtained from A1 by the gauge transformation A2=A1+∇λ with λ=21B0xy, and therefore produces the same B. Check the claimed gauge transformation directly, find the error, and state what field A2 actually produces.