Gravitational solitons on Kasner background revisited: The simplest solitons with physical context

Abstract: We revise the one-pair complex poles soliton solutions on a Kasner background. In the literature, these were rejected as solutions with no cosmological interest due to singularities that supposedly show up at space-like infinity. The only accepted solutions of this kind were those with background metric parameter $d=\pm 1$. By computing the scalars $I, J$ we find that there are no scalar singularities at all, for a wide range of the background parameter $d$. This means that there are actually an enormous number of acceptable simple complex-poles solutions, besides the $d=\pm1$ cases. These solutions are interesting, because they are much simpler than the two-pairs complex poles solutions and, consequently, it is easier to draw conclusions and relate physical phenomena to them.