Why Detecting a Parallel Universe May be Impossible

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Are there parallel universes? And how will we know? Researchers from the universities of Calgary and Waterloo in Canada and the University of Geneva in Switzerland have published a paper this week in Physical Review Letters explaining why we don’t usually see the physical effects of quantum mechanics and why it may be impossible to ever detect a parallel universe (at current levels of scientific knowledge).
“Quantum physics works fantastically well on small scales but when it comes to larger scales, it is nearly impossible to count photons very well. We have demonstrated that this makes it hard to see these effects in our daily life,” says Dr. Christoph Simon, who teaches in the Department of Physics and Astronomy at the University of Calgary and is one of the lead authors of the paper entitled: Coarse-graining makes it hard to see micro-macro entanglement.

It’s well known that quantum systems are fragile. When a photon interacts with its environment, even just a tiny bit, the superposition is destroyed. Superposition is a fundamental principle of quantum physics that says that systems can exist in all their possible states simultaneously. But when measured, only the result of one of the states is given.

This effect is known as decoherence, and it has been studied intensively over the last few decades. The idea of decoherence as a thought experiment was raised by Erwin Schrödinger, one of the founding fathers of quantum physics, in his famous cat paradox: a cat in a box can be both dead and alive at the same time.

But, according to the authors of this study, it turns out that decoherence is not the only reason why quantum effects are hard to see. Seeing quantum effects requires extremely precise measurements. Simon and his team studied a concrete example for such a “cat” by using a particular quantum state involving a large number of photons.

“We show that in order to see the quantum nature of this state, one has to be able to count the number of photons in it perfectly,” says Simon. “This becomes more and more difficult as the total number of photons is increased. Distinguishing one photon from two photons is within reach of current technology, but distinguishing a million photons from a million plus one is not.”
The Daily Galaxy via University of Calgary
Image credit: With thanks to

Written by physicsgg

December 19, 2011 at 7:17 am


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  1. If parallel universes are stacked one “over” another (for lack of a better term), I can understand that electromagnetism and the strong and weak nuclear forces wouldn’t be able to travel from one universe to another. In such a case, we might not be able to see another universe.

    But general relativity says that gravity should be able to pervade the multiverse. So in theory, an experiment should be able to find another universe by sending gravitons out of our universe or detecting gravitons coming from another universe. Some believe that’s a candidate for dark matter. Only problem is we haven’t detected gravitons, yet.


    December 19, 2011 at 8:20 pm

  2. I do believe there infinet number of universes, with infinet number of choices both Dr Who and Star Trek have done stories on this subject, it is possible that in another unvierse i am in country rock band that is/was as succesful as The Beatles, Elvis, ABBA, Michael Jackson ect., did any out there see the US Sci-Fi series Sliders where, travlerswould slip sideways in time, in another universe my home town of Leigh in Lanchashire is still part of Lancashire it still has a railway and station it’s own bus depot Leigh remaind unaltered round king street and Spinning Jenny Street, i am just saying this as an example, in this realty I’m working in a supermarket attending drama school pushing for an acting career maybe another reality i’m ready an actor, my theroy is that by 22nd December 2012 when the world supposely ends we’ll wake up in one of these other realities this reality will have been just a dream

    Gary J Waldron

    January 1, 2012 at 7:18 pm

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