Massless Stueckelberg field, exact solutions in Сartesian coordinates and gauge degrees of freedom

In the paper we examine the massless Stueckelberg field. Among the eleven field function components, the antisym-metric tensor represents the gauge variables, whereas the scalar and vector correspond to physically observable quan-tities. It is shown that in Cartesian coordinates the Stueckel-berg equations permit the existence of five independent solu-tions which describe the different states of the field. We have derived an expression for the energy-momentum tensor of the massless Stueckelberg field. We find its explicit form for arbitrary linear combination of five established solutions. We have found four combinations of five solutions which do not contribute to energy-momentum tensor, therefore they cor-respond to purely gauge states. There exists only one solution which corresponds to nonvanishing energy-momentum ten-sor, it relates to physically observable states of the massless Stueckelberg field.