The Hamiltonian for particle in an EM field is
H = 1/2m (p - qA)^2 + q phi
If we take the cross-terms, which corresponds to the paramagnetic term, we have
H para = -q/2m * (p.A + A.p )
= iqh/2m * (\nabla .A + A.\nabla)
What I do not understand is how this simplifies...