It's an interesting idea, but I feel like this is taking a lot of speculative (not observable) ideas for granted. What is a "variation in the basic parameters of matter"? Has anyone observed such a thing taking place? Also where would the universe birthing take place? I'm assuming you want me to believe the expansion of a brand new universe isn't occuring within the space of our own? I don't know how we would study new bubbles of space time, whatever those are.