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

## TL;DR

This paper revisits complex-poles soliton solutions on a Kasner background, demonstrating that many solutions previously thought singular are actually regular, expanding the set of physically relevant solutions and simplifying the analysis of related phenomena.

## Contribution

It shows that a wide range of complex-poles soliton solutions on Kasner backgrounds are free of singularities, broadening the class of physically acceptable solutions beyond the known special cases.

## Key findings

- Many solutions are free of scalar singularities.
- Simpler solutions are identified compared to two-poles solutions.
- Expands the set of acceptable cosmological soliton solutions.

## 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.