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A Mathematical Answer To the Parallel Universe Question

Posted by ScuttleMonkey on from the evil-twins-always-have-a-goatee dept.

diewlasing writes to mention that Oxford scientists have proffered a mathematical answer to the parallel universe question that is gaining some support in the scientific community. "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. 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."

6 of 566 comments (clear)

  1. One question... by StandardCell · · Score: 3, Interesting

    How does this reconcile with reality as we see it?

    From my perspective, even if this mathematical "proof" is true, it is only true in the ontological sense, i.e. that these branches can happen and maybe do happen, but not in reality. Then again, I believe the entire basis for the universe is ultimately ontological but that's a different matter.

    My point is that these alternate "universes" may only exist in infinitesimally-small times (possibly below the Planck time threshold) and then simply cease to exist again as compared with our reality in the next moment, moment after moment.

  2. Where is the paper? by kmac06 · · Score: 3, Interesting

    I would very much like to find the publication of this, or least more details given by the authors if anyone can fine a link.

    By the way, Deutsch is a well known physicist, not some crackpot. One of the first problems discovered to be theoretically sped up by a quantum computer is named after him (link).

  3. Re:Occam's razor by hanssprudel · · Score: 5, Interesting

    So, which is simpler?

    (1) Shit happens.

    (2) Shit happens. Parallel universes are created. That isn't the choice. It is more like:

    (1) (Copenhagen) The act of "observing" a particle at some point between the particle, the measuring apparatus, and your mind, somehow magically causes the particle to collapse from a wave state to a fixed one, without any other action on your part. Nobody has ever explained exactly what an observation is (we are, after all, made of particles too) nor when this happens.

    (2) (Multiple worlds) Reality consists of particles in quantum waves of superimposed states. Period. When we observe a particles state, it's state becomes entangled with the state of the particles in our mind, and hence we observe the particle as collapsing to a single state "in each world".

    I don't know about everybody else, but the fact that all states can exist, yet I can only perceive them separately, is no stranger to me than that all moments of time exist, yet I can only perceive each one separately.
  4. Re:Raises the question by kebes · · Score: 5, Interesting

    I'm not sure if you were already aware, but there is indeed a concept called "Quantum Darwinism" which helps explain (using the results from quantum decoherence) why we observe things "classically" (single outcomes of experiments, non-entangled macroscopic states, etc.) despite the universe being fundamentally quantum.

    Briefly, the theory shows (rigorously) how pseudo-classical states are the only ones that are robust against decoherence. Hence, those are the states that tend to persists for measurable periods of time. And those pseudo-classical states are the ones that give rise to other pseudo-classical states.

    Moreover the main developer of these ideas (Wojciech Zurek) describes in his papers how what we typically term "memories" are inherently classical states (it's either "a" or "b"--not a superposition of both). He explains how macroscopic states will tend to be pseudo-classical, so of course any biological (macroscopic) creature will evolve to assume that reality is classical (it's an adaptive advantage and a good approximation of reality).

    The point is that these larger-scale superpositions do indeed exist, but that local observers (e.g. instruments, or ants, or humans) can inherently only record/remember classical states, not quantum ones. So, our perception of reality (and memory of reality) is inherently a classical one.

  5. Re:idiotic circular logic by lawpoop · · Score: 3, Interesting

    The absurd number of parallel universes that would have to be created is mind boggling, since, at the very least, an entire universe would have to be created every single time any atom decayed (one for the universe where that atom happened to decay at that instant, another for the case where that atom didn't happen to decay). What exactly is the absurdity scale you are using to measure the absurdity of this idea? Four parallel universes are okay, six are goofy, seven are silly, 10 are ridiculous, and 1000 or more are absurd?

    Strange that none of the wackos who advocate this, and I use the term very loosely, "theory", bother to expain where all of the mass and energy is coming from for all of these extra universes. That's like asking where the mass and energy in our universe came from. It's the same answer in all parallel universes -- it was there all along. When they talk about a new universe branching, it's not a big bang event, where a new universe is born, it's an altered copy its twin, identical up until the point where the quantum decision was made. It has a completely identical history after a certain point and therefore, the same mass and energy. Parallel universes do not 'share' energy, nor information, nor anything else. They don't 'seed' or 'give birth to' each other. They are totally out of contact with each other. We wouldn't even know about other ones, if not for the math.

    Note that we are talking about far more universes than atoms in our own universe. Absolute hogwash. I can't see why anyone modded you insightful here. You seem to be arguing from personal incredulity. Not that I'm claiming that these guys are right or their theory is true, but your skepticism seems more emotional than rational to me.
    --
    Computers are useless. They can only give you answers.
    -- Pablo Picasso
  6. Re:Occam's razor by suv4x4 · · Score: 3, Interesting

    Reality consists of particles in quantum waves of superimposed states. Period. When we observe a particles state, it's state becomes entangled with the state of the particles in our mind, and hence we observe the particle as collapsing to a single state "in each world".

    Many people mix those up. Our "mind" doesn't have anything to do with it.

    The wave function collapses when a particle interacts with a macrosystem. When two macrosystems are separate from each other, we have to assume the other macrosystem is not coherent with us until contact.

    And remember contact *includes* photons reflected off the other macrosystem, so if we see it, otherwise put "observe" it, we're already in contact.

    This is why "observation" causes collapse. Not because we're smart.