Parallel universes have long been a staple of science fiction. But according to a radical new theory of quantum mechanics published Oct. 23 in the journal Physical Review X, other universes are real--and they exist in vast numbers.
What's more, the scientists behind the theory say the other universes exert a subtle repulsive force on our own universe--and that this force is what makes the quantum realm so mind-bendingly bizarre.
"Any explanation of quantum phenomena is going to be weird, and standard quantum mechanics does not really offer any explanation at all--it just makes predictions for laboratory experiments," Prof. Howard Wiseman, a physicist at Griffith University in Brisbane, Australia, and one of the creators of the new "many interacting worlds" theory, told The Huffington Post in an email. "Our new explanation...is that there are ordinary (non-quantum) parallel worlds which interact in a particular and subtle way."
The theory is a new twist on the so-called "many worlds interpretation" of quantum mechanics, which dates back to the 1950s. As Wiseman explained in a written statement issued by the university:
"In the well-known 'many worlds interpretation,' each universe branches into a bunch of new universes each time a quantum measurement is made. All possibilities are therefore realized--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 the name implies."
Wiseman and his collaborators--Dr. Michael Hall, also of Griffith University, and University of California, Davis mathematician Dr. Dirk-Andre Deckert--say that their theory may have important implications in the field of molecular dynamics, which is critical to understanding chemical reactions.
Does it also suggest that humans might someday be able to interact with other universes?
"It's not part of our theory...," Wiseman told Motherboard. "But the idea of interactions with other universes is no longer pure fantasy."
What do other experts make of the new theory?
Dr. Lawrence Krauss, a theoretical physicist at Arizona State University in Tempe, told The Huffington Post in an email that he was "skeptical." And a popular Czech Republic physicist wrote on his blog that while Wiseman and his collaborators had "managed to present some ideas that are at least slightly original," their paper was "another example of the fact that such efforts are a hopeless enterprise and a huge waste of time."
But Charles Sebens, a philosopher of physics at the University of Michigan in Ann Arbor, told Nature that he was excited by the approach taken by Wiseman and his collaborators.
“They give very nice analyses of particular phenomena like ground-state energy and quantum tunneling," he told the journal. “I think that together they do a nice job presenting this exciting new idea.”
Dr. L. William Poirer, professor of chemistry at Texas Tech University in Lubbock, also expressed support for the "many interacting worlds" theory. He told HuffPost Science in an email that Wiseman and his collaborators had made "an important contribution...There is no experimental evidence to support this yet, but if true, it means that their theory will make different experimental predictions than standard quantum mechanics does."
Clearly, there's no consensus. But if Wiseman is dismayed by the uneven reaction to the theory, he's not letting on.
"There are some who are completely happy with their own interpretations of QM, and we are unlikely to change their minds," he said in the email. "But I think there are many who are not happy with any of the current interpretations, and it is those who will probably be most interested in ours. I hope some will be interested enough to start working on it soon, because there are so many questions to answer."
In the meantime, the last word should probably belong to Nobel Prize-winning theoretical physicist Richard Feynman (1918-1988), who once said, "I believe I can safely say that nobody understands quantum mechanics."