Suppose at some point the universe ceases to expand, and instead begins collapsing in on itself (as in the “Big Crunch” scenario), and eventually becomes a supermassive black hole. The black hole’s extreme mass produces an extremely strong gravitational field. Through a gravitational version of the so-called Schwinger mechanism, this gravitational field converts virtual particle-antiparticle pairs from the surrounding quantum vacuum into real particle-antiparticle pairs. If the black hole is made from matter (antimatter), it could violently repel billions and billions of antiparticles (particles) out into space in a fraction of a second, creating an ejection event that would look quite similar to a Big Bang.
The idea of a cyclic universe is not new. As Hajdukovic notes in his paper, in 1922 cosmologist Alexander Friedmann noticed that Einstein’s theory of general relativity is compatible with the framework of a cyclical universe. More recently, cyclic models have included loop quantum gravity, braneworld theories, and other “Big Bounce” models. However, unlike Hajdukovic’s scenario, in all of these models, all cycles are dominated by matter. As Hajdukovic explains, he is not offering a new cyclic model of the universe, but simply a mechanism that could, in principle, have allowed the transition from a matter-dominated universe to an antimatter-dominated universe, and vice versa.
http://www.physorg.com/news/2011-07-big-quick-conversion-antimatter.html
