... "quantum particle creation could play a role in the creation of matter in the universe after the end of an inflationary era" ...

The way i read it : Our theoretical framework, allowing matter creation (*) provides a possible origin for the universe (without the need of a Big Bang). Also this is quite timely in the actual context of new observations made by the James Webb space telescope that are in tention with classical models.

(*)(after an hypothetical inflatory period, […or at any time as long as the universe expands…])

title of this post is taken from section : VII. SUMMARY
Of : Cosmological Particle Production: A Review

Preprint :
(2021 December 7 // @ arXiv…)
arxiv.org/pdf/2112.02444.pdf

The article has been published in a peer reviewed journal paywall warning.