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.
Dragan Slavkov Hajdukovic, a physicist on leave from Cetinje, Montenegro, currently working at CERN in Geneva, Switzerland, emphasizes that he has no idea if this scenario occurred 13.7 billion years ago or not. But in a recent study published in Astrophysics and Space Science, he has described a mechanism that can convert matter into antimatter (or vice versa) that results in a cyclic universe that is successively dominated by matter and antimatter. In this scenario, when a matter-dominated universe collapses, an antimatter-dominated universe emerges, and the cycle continues indefinitely.