What kind of topology change does this Lorentzian metric describe?

[Onyx]

TL;DR Summary

What kind of topology change does this Lorentzian metric describe?

Looking at this paper, what sort of spatial topology change does the lorentzian metric (the first one presented) describe? Does it describe the transition from spatial connectedness to disconnectedness with time? All I know is that there is some topology change involved, but I don’t see the paper specifying what kind. Also, why is $t$ periodic? That seems very unusual to me.

 

[martinbn]

Which one do you call the first example? The one that says that it is Wheeler's beloved wormhole? Then it describes the change from nothing to a wormhole $S^1\times S^2$.

 

[Onyx]

No, when I say the first example, I mean number 7, the Lorentzian metric with the off-diagonal entries.

 

[martinbn]

No, when I say the first example, I mean number 7, the Lorentzian metric with the off-diagonal entries.

That is the same example!

 

[Onyx]

That is the same example!

Oh, my bad.

 

[Onyx]

Oh, my bad.

Well then I suppose $t=0$ represents nothing and $t=1$ represents the $S^3$ wormhole having formed.