  We address a problem of proper definition of momentum density for spatially
structured electromagnetic fields. We show that the expressions for the
momentum and angular momentum obtained locally are not the same when one uses
the canonical energy-momentum tensor instead of the symmetric Belinfante
energy-momentum tensor in electrodynamics. This has important consequences for
interaction of matter with structured light, for example, twisted photons; and
would give drastically different results for forces and angular momenta induced
on small test objects. We show, with numerical estimates of the size of the
effects, situations where the canonical and symmetrized forms induce very
different torques or (superkick) recoil momenta on small objects or atomic
rotors, over a broad range of circumstances.
