Schild's Ladder

Schild's Ladder (ISBN 006107344X) is a 2002 science fiction novel by Greg Egan.

Warning: Spoilers follow

This novel is perhaps the hardest ever published by Egan, filled with non-trivial mathematics and physics. A two-millimiter high physicist, Cass, starts an experiment that inadvertantly creates a bubble of - it seems - void, expanding at half the speed of light. But, inside this bubble, Egan's usual topics of simulation and virtual reality are taken to the extreme when we learn that life is thriving inside this zone of apparent destruction; sustained not on physical particles, but on constantly changing laws of physics that provide a framework for intelligent beings to exist.