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Writer's quantum entanglement Qs (help!)

  1. Sep 16, 2010 #1

    I'm currently writing a novel that incorporates kernels of truth from current quantum physics theories and experiments. Please note that I am 100% layperson where this topic is concerned. I've tried to do my 'homework' by reading books geared toward folks like me.... not smart enough to be a real physicist, but fascinated by that world nonetheless. Sadly, I don't personally know anyone in the field and despite asking friends and family, have come up with my hands empty. In short... I... have... no...physicist... friends (sniff). I feel very uncool. Will you be my (patient) cyber physics friend? (haha).

    Ok, in all seriousness... I could really use help, here. As I said above, I am taking liberties w/ quantum physics theories and findings while writing my novel. One aspect is quantum entanglement. My dumbed-down understanding of it is that entangled photons (2 or more) are inextricably linked, regardless of distance. It is NOT a physical entanglement like depicted in some sci-fi shows where the good guy "merges" with his doppleganger. The photons are not physically anywhere near each other-- and while they each exist, they behave as if they were only one (the same) photon. The result is that whatever happens to one automatically affects the other.

    From what I understand, there is evidence that human can see quantum entanglement with the naked eye. http://www.wired.com/wiredscience/2009/09/quantum-entanglement/ . I *fully* understand that current science does not suggest that human beings are entangled. No one has outright said it is impossible, b/c one doesn't do that in science -- but it is highly improbable.

    But this is what fiction is for (right?) and in my book some folks are...just...entangled. Now, I am not writing 'science fiction.' I am writing 'geek fiction', which means that even though I include things that are highly improbable, I want the premise to be based on real science and what is currently known/theorized. In other words, I wouldn't want to explain entanglement between two people as the result of, say, alchemy. Or gamma rays. Or aliens alchemists who use gamma rays.

    Assume for the sake of my story plot that there really is a multiverse and that splitting occurs so that every possible outcome happens somewhere. We're talking here only about those parallel universes that have physics laws the same as our own; "close" parallel universes. So let's say in our world, Lucy pulls the football so that Charlie Brown falls. In the parallel Universe, she lets him kick the ball and a scout sees him and offers him a scholarship to pee wee football university. In my freaky-fiction-geek world, the two Lucys and two Charlies are entangled.

    Given that, here are some (most assuredly really stupid) questions I have.

    1. From what I read, entangled photons do not act exactly the same. Once observed, if one has an up spin, the other will have the opposite spin. What does this mean for our Lucys and Charlies? If Charlie Brown gets upset with the Lucy in our world and he stomps away, fuming does the other Charlie feel the same way -- fuming, though inexplicably to him -- or does he behave in an opposite way (like the spins) and he's suddenly inexplicably very happy? Or, what if Lucy, her usual manipulative self in our world, pulls the football and she gets satisfaction from seeing him fail, while in another universe she allows him to kick it and she instantly falls in love with him b/c he turns out to be a world record kicker? If they are entangled, what might happen in this scenario?

    2. And, let's say at the same exact time the entangled Lucys are engaged in different activities. Our world Lucy is swimming. The other world Lucy is skiing. Swimming Lucy gets a sunburn while skiing Lucy gets frostbite. Would they each feel both frostbite and sunburn simultaneously, or would they 'switch' feelings?

    I guess what I need help working out is IF someone ever came up with proof that people can become entangled, what exactly might it look like? And what would happen it they "decohered", and how would that come to pass?

    Finally (for now, anyway), there is one thing about the multiverse idea that I don't get. Let's say I am with my little kids (I have twins) and I'm feeding them dinner. One throws a plate of food and the other runs upstairs. In this world I ignore the tantrum and running off. I split, and in other world I make the one kid clean up the mess and the other has to come down to finish dinner. In another, I just send both kids out to play... and so on. But wouldn't the splitting have to be based on what everyone is doing at that moment? So not only is it me splitting of, it is a combination and permutation of every. single. thing. that could happen.

    So if I make a matrix of the possible actions for the three of us, the # of 'new' universes caused by splitting is.... even for just three people and one situation.... infinite. (What is in one I decide just to sell the kids on ebay?)

    Please help me wrap my head around this.

    I owe you, friend(s). And please continue to tolerate me, as I have other questions for you. I promise if my book gets published you'll get a signed copy for you in this world and all the yous in the branching universes.

  2. jcsd
  3. Sep 16, 2010 #2
    You're talking about something like what is known as the "Many Worlds" Interpretation of QM (Quantum Mechanics). In that, there is no link between photon "A (call it Alice for convention" and photon "B (Call it Bob)" of the type you describe. On one hand you're talking about two universes that are entangled at a macroscopic scale, but NOT two "realities" as in the general MWI (Many Worlds Interpretation). Such macroscopic emergence of quantum behavior is generally considered impossible, because while one photon, or an atom might undergo a spin flip as a result of entangled state, they will undergo decoherence as they are perturbed. Add more particles or atoms to a system, and that happens even faster.

    What MWI talks about is a lack of wavefunction collapse, and not entanglement: every possible solution (to simplify) occurs in a separate universe or reality... yadda yadda. In one reality, Schrodinger's cat is dead, and in the other, alive, but this is an example meant to convey a microscopic principle. That principle is that rather than a single photon taking multiple paths to say, a detector screen, it takes one path in each "world", with an outcome in many worlds.

    On a HUGELY macroscopic level, you could (like the episode of futurama) have universes in which the only difference is that the outcome of flipping a coin is reversed. This doesn't mean that if you cut someone in Universe A, they have a twin in B to bleed as well. In fact, most configurations in MWI doesn't even have life, never mind an organized universe.

    If you want to write about the things you're talking about, and I'm not judging your story, this isn't the physics to support it... there's a reason it's called "fiction"

    I hope this helps, and as a caveat there are many here, in fact, many many MANY who are far better at the physics, math, and subsequent explanations than I am.
  4. Sep 16, 2010 #3
    As stated above, entanglement is not the physical phenomina you want to use to explain the scenerios you described. The only plausable explaination I can think of would be if Charlie and Lucy are simulated people existing in simulated worlds constucted by some advanced race for the purpose of predicting human behavior and outcomes given various changes such as wether Lucy pulls the football. In this cenerio a programming glitch could let variables from one simulation be used in another. If the simulations were sufficiently advanced Charlie and Lucy would percieve themselves and their worlds to be real and have no explaination for the strang effects of the programmign glitch.

    I don't know if such a framework works for your story. Take it for what it's worth. If you use it and your book sells a million coppies and you become rich you owe me a pizza ;-)
  5. Sep 16, 2010 #4
    That sounds pretty good to me! Another idea, would be that Charlie and Lucy are connected, and the means of communication is entanglement. As long as they're within a few light seconds of each other, it would be VERY quick, and not detectable in the way that a radio signal might be.
  6. Sep 17, 2010 #5
    Huh? What? You mean we're *not* a computer simulation created as a plaything for an advanced race? (smile). Thanks for the input & ideas. Nismar, when you say, 'connected' do you mean as in some sort of quantum telepathy type of communication? (Did I just embarrass myself again?)

    E-gads, I'm confused about things, aren't I...You know, I gotta say--strictly from an uneducated perspective--that the terminology makes things confusing. It seems "universe" and "world" are often used interchangeably.

    Anyway.. Ok, another question. Y'know the findings back in the spring where folks @ UC Santa Barb demonstrated the whole one-thing-in-two-places with an object large enough to be seen w/ the naked eye? So, the whole superposition thing, using some sort of mechanical resonator. Presumably research marches forward and now that it's been done someone will do it with something even bigger. I feel like I oughta be able to work this in somewhere. (?)
  7. Sep 18, 2010 #6
    When you lead with, "I'm a writer, not a physicist" you don't embarrass yourself, especially when dealing with a very complex issue in QM. You're not right about telepathy, because that implies the ability to communicate with or read minds directly. Even if you had a bit of your brain that was macroscopically entangled with another, what means do you have to interpret that as language or thoughts? More likely, the first spin flip would just kill you.

    That doesn't mean that you can't WRITE that however, and here's one idea... you have people who... for reasons we can't yet imagine do have a portion of their brains which communicates with alternate universes occupying the SAME SPACE (important) or a nearby region (light seconds ideally). You can't violate light-speed without resorting to fiction, but if you're close enough spatially (and you fudge the rest) then there's only as much delay in the comms as there are light-seconds/minutes/years.

    You would have to invent the physiology or science to achieve such a connection and ability to interpret it, but that's where the fiction comes in. You see, this isn't the kind of connection that I meant... it's just the simple spin-flip (at its most basic) connection of normal entanglement.

    You're correct about the oscillator that was... I think... 40 microns and placed into what is called a "Superposition" of both vibrating, and not vibrating at what is arguably a macroscopic scale. HOWEVER... this is a completely different beast from Entanglement (aka non-locality).

    Take the following with several grains of salt, but it isn't bad: http://en.wikipedia.org/wiki/Quantum_superposition


    http://en.wikipedia.org/wiki/Quantum_entanglement http://en.wikipedia.org/wiki/Non-locality

    What you need to understand above all, and what you'll have to imagine in the fictional department, is that the more elements: particles, atoms, and more... that you put into system, the less likely it is to demonstrate what might be termed as "quantum weirdness". There are hefty ongoing debates as to whether there is some magical threshold, or if Decoherence http://en.wikipedia.org/wiki/Decoherence or some other mechanism is at play in these matters.

    To put it simply, if you're small and made of few "parts" in an isolated and low energy system (that oscillator was super-cooled, lower energy, less motion) that is less likely to be perturbed, you can maintain the "weirdness" for a long time, relatively speaking. The more a system is perturbed, and that goes up as it has more elements, the shorter the time-scale for the 'weirdness', down past nanoseconds and into the currently unmeasurable scales with current tech. To confront this, you'll need to use imagination and fiction based on the essential principles, but if you write with complete scientific fidelity, your plot (which sounds fun to me) dies.
    Last edited by a moderator: Apr 25, 2017
  8. Sep 19, 2010 #7
    thank you. this is all very helpful. i believe i'm beginning to understand the differences. i am determined to at least get a basic grasp, though i suspect that you are right. i don't understand enough to write scientific realism, at least where QM is concerned! i mean, hey -- Fringe hardly has scientific fidelity and look at the hit it is (though I understand scientists have a good ol' laugh over it!)
  9. Sep 19, 2010 #8
    Entanglement can not be used for communication.

    Whatever happens to system A cannot effect system B in any measurable way. Entanglement has to do with what you can infer about system B based on your measurement of system A. For example, a source can send particles in two opposite directions in such a way that their spin points in opposite directions. Now, when you measure the spin of a particle, you will get a result of +1 or -1 in a particular direction. The probability of getting +1 or -1 depends on the superposition of spin eigenstates that the particle is in. By making the measurement, the system is forced into a particular eigenstate, such that by repeating the same measurement, you get the same result. If you perform a measurement along the same axis on the other particle, the result will be consistent with the measurement of particle A, since the particles were in a superposition of states, each having the spins pointing in opposite directions. If the measurement on particle A gave you +1, the measurement of particle B necessarily gives you -1. If the measurements are done in perpendicular directions, the results are not correlated at all, no matter what is measured for particle A, the outcome for particle B is completely random.

    The strangeness lies in the result you get when measuring the particles at an angle in between 0 and 90 degrees. The amount of correlation between the measurements depends on the angle in a way that can't be explained in any way other than that the system consisting of the two particles were in a superposition of states until they were measured. (By measuring the system, the state of the experimenter himself, and the rest of the world, becomes entangled with the state of the measured system) So, this is how it is determined the the particles were entangled.

    Of course, any further disturbances to either particle won't affect the other particle at all.
  10. Sep 20, 2010 #9
    thanks, this also helps! i sure would love to be able to see this in action in the lab. maybe one day.
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