The concept of parallel universes has been depicted frequently in science fiction, without any real evidence that they actually exist. Howard Wiseman of Griffith University in Australia led a team that believes quantum theory allows for multiple versions of our universe to exist and overlap, and even interact with one another on the quantum level. Michael Hall is the lead author of the paper, which was published in the journal Physical Review X.
Studying the nuances of quantum theory can get tricky, as things behave contrary to what would be expected from ordinary matter. Quantum states of a system are believed to simultaneously exist in all possible configurations until an observer forces it to adopt one state.
In the mid-20th century, the ‘Many Worlds’ theory first speculated that multiple versions of reality branch out from one another as distinct entities existing in discrete locations, without any interaction. This new theory suggests that all of these infinite multiple worlds overlap and occupy the same region of time and space simultaneously, just like a quantum state.
“All possibilities are therefore realized – in some universes the dinosaur-killing asteroid missed Earth. In others, Australia was colonized by the Portuguese,” Wiseman said in a press release. “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.”
Under this new interpretation, some worlds in parallel universes would be nearly identical. In others, the “Butterfly Effect” is responsible for completely different outcomes. Each universe is equally real; it isn’t that one universe is the truth while others are bizarre copies or lesser in any way. Wiseman also believes that the quantum forces responsible for driving this shared existence are also responsible for causing quantum interactions between the worlds. Similarity between worlds interact through quantum forces, which influences the outcome of the world by making them slightly dissimilar. Though the theory states that the worlds interact with one another on the quantum level and not on a larger scale, Wiseman also believes the theory does not preclude that possibility, either.
“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. In between it predicts something new that is neither Newton’s theory nor quantum theory,” Wiseman continued. “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.”
Response from the physics community has been varied. Luboš Motl described Wiseman’s paper as “a hopeless enterprise and a huge waste of time.” Charles Sebens from the University of Michigan, on the other hand, is more aligned with Wiseman. Using a different line of thinking, he came to a very similar conclusion and told Nature: “They give very nice analyses of particular phenomena like ground-state energy and quantum tunneling.”
Of course, the big obstacle now is determining how Wiseman’s ideas could be tested and how to detect quantum variations that could indicate interactions with another world.