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More Than One Reality Exists (in Quantum Physics) (livescience.com)

Posted by EditorDavid on from the Schrodinger's-cat(s) dept.

Zorro (Slashdot reader #15,797) quotes Live Science: Can two versions of reality exist at the same time? Physicists say they can -- at the quantum level, that is.

Researchers recently conducted experiments to answer a decades-old theoretical physics question about dueling realities. This tricky thought experiment proposed that two individuals observing the same photon could arrive at different conclusions about that photon's state -- and yet both of their observations would be correct.

For the first time, scientists have replicated conditions described in the thought experiment. Their results, published Feb. 13 in the preprint journal arXiv, confirmed that even when observers described different states in the same photon, the two conflicting realities could both be true. "You can verify both of them," study co-author Martin Ringbauer, a postdoctoral researcher with the Department of Experimental Physics at the University of Innsbruck in Austria, told Live Science.

13 of 114 comments (clear)

  1. that explains politcs! by kiviQr · · Score: 4, Insightful

    ...we knew it for long time

    1. Re:that explains politcs! by Tablizer · · Score: 2

      It's fake news and very fake news at the same time!

      --
      Table-ized A.I.
  2. Duh!!!! by NoNonAlphaCharsHere · · Score: 2

    Every time I talk to my boss, I know there's more than one reality.

    1. Re:Duh!!!! by Tablizer · · Score: 2

      Every time I talk to my boss, I know there's more than one reality.

      The Milton Effect: You are fired and working at the same time. The boss just hasn't told you yet.

      --
      Table-ized A.I.
  3. Not Necessarily by Roger+W+Moore · · Score: 3

    The paper indicates that one of three assumptions must be wrong with the other two being: free choice and non-locality. My bet is on the latter. However, one aspect of this particularly dense paper that I do not quite grasp yet is that it seems that the suggested experiment requires measuring the state of an entangled photon non-destructively which I understood to be impossible...but it is possible I misunderstood.

    1. Re:Not Necessarily by Xylantiel · · Score: 2

      I think this is terribly mischaracterized even in the paper. They say that the assumption they think is violated is something like "there is an objective reality" and so the reality can be different for the two observers. But, as best I can tell, what they mean by an "objective" answer is that there is a hidden variable. We already knew that there are no hidden variables, so it's not surprising that this experiment also shows the assumption of a hidden variable must be violated. While this is a really nice realization of this thought experiment, I don't see how it adds anything new to our understanding of quantum mechanics, it just confirms what we already knew. I'm pretty sure that one of the things we already knew is that phrasing things in terms of "wave function collapse" is not a good way to think about it (easily leads to misleading conclusions). This is why the many-worlds interpretation already exists.

    2. Re:Not Necessarily by SoftwareArtist · · Score: 2

      Actually, we don't know that there are no hidden variables. Quite the contrary, lots of hidden variable theories are still consistent with all known experiments. You've probably been misled by the nonsense that gets published every time someone tries to do a new test of Bell's inequality. Most of those articles are just as confused as this one. Remember that all those "experimental proofs" that the wavefunction is real, that measurements are random, that hidden variables don't exist, and so on are actually based on a long list of assumptions. Locality, no retrocausality, no contextuality, fair sampling, and so on. None of those assumptions are justified in any way, either from theory or experiment. And at least one of them (fair sampling) is patently absurd.

      --
      "I'm too busy to research this and form an educated opinion, but I do have time to tell everyone my uninformed opinion."
  4. Wigner's friend by Okian+Warrior · · Score: 5, Informative

    For a little more clarity on the subject, this is a physical realization of the "Wigners Friend" experiment. The "state" referred to in the summary is "superposition/collapsed waveform", and not the specific information about the photon such as its spin.

    In the experiment, one scientist ("Wigner's friend") observes a photon in a superposition of states, which collapses the state, while a second scientist observes the first scientist. This uses entangled photons, so that observing the first photon collapses the state of the second.

    The first scientist observes one photon, thereby collapsing its state to reveal information. Does the second scientist see his photon in a superposition or collapsed state? The first scientist might even tell the 2nd that he has observed the photon, collapsing its state - but not sating what state information was seen.

    According to the experiment, the 2nd scientist still sees his photon in a superposition of states even though he knows that the first scientist has observed the photon and that the first scientist knows what the collapsed state is.

    1. Re:Wigner's friend by Anonymous Coward · · Score: 2, Interesting

      None of which suggests what the article summary implies: parallel realities. Everything in your experiment involves two people interacting with one another in one shared space-time continuum.

      The whole "multiverse" thing annoys me because it is intrinsically non-falsifiable. It gets a lot of attention because a specific group of physicists who favor this model happen to be famous and popular. So people think this is a done deal. And it's not. Just as many, just as smart and just as prominent physicists do not accept this model.

      No, I won't give you links. You can find your own links if you actually care, which you don't.

    2. Re:Wigner's friend by burtosis · · Score: 4, Interesting
      It's a bit clickbaity as the experimenters themselves say

      In contrast to standard Bell inequalities, (the probability distribution) is not concerned with the coexistence of local properties for two separate physical systems, but rather with the coexistence of facts with respect to different observers.

      Yet this apparent discrepancy in observed measurements, or "facts about the world being observer independent" has several loopholes including locality, freedom of choice, and the detection loophole (only a fraction of photons are successfully detected). The locality and freedom of choice loopholes can be removed by sufficiently seperating the events in space. Neither of these was able to be done in this experiment. Further you would need to ensure that the measurement of the observers "memory" (an observer could simply be an instrument, sensor, or interaction of matter/energy of some kind and not a person) and are clearly independent systems initially.

      Tl:dr this is less about showing multiple realities exist and more about showing how the "cut" between indeterminate quantum and deterministic classic macro systems work. A good discussion is here

  5. And what are they? by Okian+Warrior · · Score: 2, Insightful

    More than one reality In Donald Trump's head.

    The current realities are in flux - can you be more specific here?

    Is he still "literally Hitler", or has that reality been discarded?

    How about "is going to rot in federal jail, along with his family"? Will that reality happen any time soon?

    I think the "anti-semite" reality was dealt a death blow by moving the embassy to Jerusalem, but if that didn't kill it the Golan Heights thing surely did.

    Or is he still an anti-semite after all that?

    The "racism" reality is still going strong, despite having done more for minorities than any other president in living memory (by reforming the sentencing guidelines). Also, illegal immigration disproportionately hurts minorities, and minority unemployment is the lowest it's ever been.

    Is he still racist after all that?

    Which realities are you referring to, that appear in Trump's head?

    We're all dying to know what you think!

  6. Re:And in other news by Jeremi · · Score: 3, Insightful

    But I guess they have never heard of KISS.

    The problem is that Quantum Physics already uses the KISS method -- it's just that universe behaves strangely enough that this is the simplest theory they can (currently) come up with that hasn't been already falsified by measured results. Plenty of beautiful, simpler theories (Newtonian mechanics, aether, etc) have already been tried and found wanting.

    Correlary: if/when they ever do figure out How The Universe Really Works, it will probably be even weirder and more counterintuitive than their current theories. Buckle up!

    --


    I don't care if it's 90,000 hectares. That lake was not my doing.
  7. It's too early ... by CaptainDork · · Score: 3, Insightful

    ... to ink this one in.

    Recall the twin paradox and the loss of simultaneity with Special Relativity. The phenomenon are both "apparent," and "true," depending on the frame of reference.

    It took years for that to be accepted and to morph into intuition.

    Quantum mechanics is in its infancy and it will be 30-40 years before we get to the same comfortable place.

    --
    It little behooves the best of us to comment on the rest of us.