In a radical new theory, scientists have proposed that parallel universes really do exist and they interact with one another.
Professor Howard Wiseman and Dr Michael Hall from Griffith University's Centre for Quantum Dynamics in Australia, and Dr Dirk-Andre Deckert from the University of California, have proposed that parallel universes exist, and rather than evolving independently, nearby worlds influence one another by a subtle force of repulsion.
The researchers said that such an interaction could explain everything that is bizarre about quantum mechanics.
Quantum theory is needed to explain how the universe works at the microscopic scale, and is believed to apply to all matter. But it is notoriously difficult to fathom, exhibiting weird phenomena which seem to violate the laws of cause and effect.
The "Many-Interacting Worlds" approach developed at Griffith University provides a new perspective on this.
"The idea of parallel universes in quantum mechanics has been around since 1957," said Wiseman.
"In the well-known "Many-Worlds Interpretation," each universe branches into a bunch of new universes every time a quantum measurement is made.
"All possibilities are therefore realised - in some universes the dinosaur-killing asteroid missed Earth. In others, Australia was colonised by the Portuguese.
"But critics question the reality of these other universes, since they do not influence our universe at all. On this score, our "Many Interacting Worlds" approach is completely different, as its name implies," he said.
Wiseman and his colleagues proposed that the universe we experience is just one of a gigantic number of worlds. Some are almost identical to ours while most are very different.
All of these worlds are equally real, exist continuously through time, and possess precisely defined properties, they said.
All quantum phenomena arise from a universal force of repulsion between 'nearby' (ie similar) worlds which tends to make them more dissimilar, they added.
Hall said the "Many-Interacting Worlds" theory may even create the extraordinary possibility of testing for the existence of other worlds.
"The beauty of our approach is that if there is just one world our theory reduces to Newtonian mechanics, while if there is a gigantic number of worlds it reproduces quantum mechanics," he said.
"In between it predicts something new that is neither Newton's theory nor quantum theory.
"We also believe that, in providing a new mental picture of quantum effects, it will be useful in planning experiments to test and exploit quantum phenomena," Hall said.
The study was published in the journal Physical Review X.
