  It has been accepted that the polarization of the photon in vector beams is
entangled with its momentum. Here a quantum description is advanced for the
polarization that shows entanglement with the momentum. This is done by showing
that the Jones vector at each value of the momentum plays the role of the
polarization wavefunction in the sense that the Pauli matrices represent the
Cartesian components of the polarization in the local reference system with
respect to which the Jones vector is defined. The unit vector that the
constraint of transversality condition requires to specify the local reference
system turns out to be a gauge degree of freedom that determines the
entanglement of the polarization with the momentum and has observable effects.
