The photomagneton and photon helicity

It is shown that the real and physical Pauli-Lubansky pseudo-four-vector (Vμ) dual to the electromagnetic four-tensor in free space is proportional to photon helicity. Therefore Vμ is rigorously non-zero, showing that the photomagneton is rigorously non-zero in the theory of special relativity. In the conventional approach to free space electromagnetism, the photomagneton is at best not considered (because it is not a transverse wave), and at worst asserted to be zero. Physical effects are expected from the interaction of with matter. The vector Vμ contains the expectation value (Bz) of as its space-like and time-like component, i.e. Vμ = ε0c(0,0,Bz,iBz). The imaginary pseudo-four-vector Wμ = −iε0(0,0,Ez,iEz) is dual to Vμ in free space, but its components are unphysical because they are imaginary. Therefore Bz in free space is dual to an imaginary and unphysical longitudinal electric field