Photon propagator in de Sitter space in the general covariant gauge

We consider a free photon field in $D$-dimensional de Sitter space, and construct its propagator the general covariant gauge. Canonical quantization is employed to define system starting from classical theory. This guarantees that satisfies both equation of motion subsidiary conditions descending gauge invariance fixing. first as sum-over-modes momentum carefully accounting for symmetry properties state. then derive position space representation, our main result. Our conclusions disagree with previous results we find necessarily breaks symmetry, except exact transverse limit.