Parallel universes aren’t just the stuff of sci-fi, according to a mathematical discovery by Oxford scientists. The breakthrough is being described as "one of the most important developments in the history of science".
The parallel universe theory was first proposed back in over half a century ago in 1950 by US physicist, Hugh Everett. The theory helps make sense of the many mysteries of quantum mechanics that have left scientists scratching their heads for decades. In Everett's "many worlds" universe, every time a new physical possibility is explored, the universe splits off. For each possible alternative outcome, each one is played out in an alternate universe. The implication would mean that the number of alternative scenarios in every individual’s lives would be bizarrely and unfathomably endless.
Partly because the idea is so uncomfortably strange, it’s dismissed as sci-fi by many critics. But there are also many credible, respected proponents of the theory—a group that is continuously gaining new adherents as new research unveils new evidence. The new research stemming from Oxford now—for the first time—offers a mathematical answer that sweeps away one of the key objections to the controversial idea. Their research shows that Dr Everett, a Phd student at Princeton University back was indeed on the right track when he came up with his multiverse theory.
Dr Andy Albrecht, a physicist at the University of California at Davis commented, "This work will go down as one of the most important developments in the history of science."
According to quantum mechanics, nothing at the subatomic scale can really be said to exist until it is observed. Until then, particles occupy uncertain "superposition" states, in which they can have simultaneous "up" and "down" spins, or appear to be in different places at the same time. The mere act of observing somehow appears to "nail down" a particular state of reality. Scientists don’t yet have a perfect explanation for how it works, but that hasn’t changed the fact that the phenomenon appears to be real.
According to quantum mechanics, unobserved particles are described by "wave functions" representing a set of multiple "probable" states. When an observer makes a measurement, the particle then settles down into one of these multiple options, which is somewhat how the multiple universe theory can be explained.
The Oxford team, led by Dr David Deutsch, showed mathematically that the bush-like branching structure created by the universe splitting into parallel versions of itself can explain the probabilistic nature of quantum outcomes.
The work has another very strange implication. The idea of parallel universes would apparently sidesteps one of the key complaints with time travel. Every since it was given serious credibility in 1949 by the great logician Kurt Godel, many eminent physicists have argued against time travel because it undermines ideas of cause and effect to create paradoxes. An example would be the famous “grandfather paradox” where a time traveler goes back to kill his grandfather so that he is never born in the first place.
But if parallel worlds do exist, there is a way around these troublesome paradoxes. Deutsch argues that time travel shifts happen between different branches of reality. The mathematical breakthrough bolsters his claim that quantum theory does not forbid time travel. "It does sidestep it. You go into another universe," he said. But he admits that there will be a lot of work to do before we can manipulate space-time in a way that makes “hops” possible. While it may sound fanciful, Deutsch says that scientific research is making the theory sound much more believable.
"Many sci-fi authors suggested time travel paradoxes would be solved by parallel universes but in my work, that conclusion is deduced from quantum theory itself."
Posted by Rebecca Sato
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