The problem of nonconservation of the electromagnetic current for two-boson systems on the light front obtained by truncation of the quasi-potential expansion is studied. We found that current conservation can be restored by a subtle choice of the truncation of the expansion of the current operator, while the naive truncation of the expansion of both current and effective interaction violates covariance and current conservation. The framework allows to treat at the same level the current operator for bound and scattering states. The generalization to two-fermion systems is briefly discussed.
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