I was once reading a book about a civilization that escaped into an electron after the galaxy had a core explosion. They did this again and again, many levels, sometimes into 4+ dimensional spaces. I left the book on an airplane and did not read the whole book and forgot the author/title. I'd like to find the book again - it was a great book. Does it ring a bell for anyone?
The book is Diaspora by Greg Egan.
The original idea was to widen electron wormhole mouths to make the wormholes large enough to be traversable, and then use the wormholes to hop between the stars. This is based on Kozuch Theory, an Egan invention where all elementary particles are wormholes. The wormholes produced were traversable but useless as they took just as long to traverse as geodesics in normal space. Eventually civilization traveled to the stars by conventional means and discovered a planet with high concentrations of the heaviest stable isotopes of several common elements. Excerpt:
YATIMA: I think I know what the Transmuters wanted us to find.
ORLANDO: I doubt it.
YATIMA: What do you add to hydrogen to make deuterium? What do you add to carbon-12 to make carbon-13? (gently) It's been staring us in the face.
ORLANDO: Neutrons are neutrons. What is there to find? What is there to travel eighty-two light years for?
YATIMA: Neutrons are wormholes. And if Blanca's dead clone was right, the Transmuters had all the degrees of freedom they could need to make Swift's neutrons unique.
Eventually they figured out how to use the special neutron wormholes the Transmuters left behind and used them to migrate to other universes.