1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Quantum decision affects results of measurements taken earlier in time

Discussion in 'science and environment' started by xes, Apr 24, 2012.

  1. xes

    xes F.O.A.D

    http://arstechnica.com/science/news...-results-of-measurements-taken-beforehand.ars
    http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys2294.html (subsciption needed)

    brain goes nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnngggg to this sort of stuff, but it's still pretty cool so I share.
     
  2. littlebabyjesus

    littlebabyjesus would be a rubbish god

    Yeah, that's a variant on similar experiments I've read about before. Everyone's brain goes nnnnnnnnnnnnnnnnnnnnnggg on this a bit at the moment, xes. You're in good company. :)
     
  3. Crispy

    Crispy Fond of drink and industry

    Nah, it's simple, cos the entanglement after the fact reflects the measurement you ma... no hang on, it's because you make the measurement which then affects the choice of whether or not you... no hang on it's because you can't measure it unless you choose to... no hang on. HNNNNNNNG
     
    beesonthewhatnow and stuff_it like this.
  4. xes

    xes F.O.A.D

    can we just all agree that it's either magic, or god did it.
     
    fogbat likes this.
  5. fractionMan

    fractionMan Custom Title

    hedsplode
     
  6. xes

    xes F.O.A.D

    If I learn quantum physics in the future, can I understand it now?
     
  7. EastEnder

    EastEnder Brixton Barnacle

    Surely the key point here that whilst Alice & Bob's photons may have correlated polarisations, dependent on what Victor subsequently does, neither of them actually know whether they do or not. Unless they phone each other to swap notes, as it were. So the system is entangled, but none of the players know any more than they would in a classical system, unless they resort to traditional means of communication. To put it another way, there's no way for Victor to change past events by deciding whether or not to entangle his photons based on what Alice & Bob have already done, because he doesn't know what they've done - and if he did know, that would be a form of measurement, collapsing the quantum nature of the system.

    Possibly. I may be talking rubbish...
     
    existentialist likes this.
  8. stuff_it

    stuff_it Nerd burglar

    Hnggggggg
     
  9. alsoknownas

    alsoknownas some bloke

    There's another famous delayed-choice experiment, which is more closely linked to the classic two-slit experiment.
    [​IMG]
    Read all about it:
    http://news.sciencemag.org/sciencenow/2007/02/16-04.html
    (After a Short Delay, Quantum Mechanics Becomes Even Weirder - Science Now, Feb 2007)

    Don't ask me to explain any of this shit :confused:.
     
  10. Greebo

    Greebo Laquelle lettre de "non" n'as tu pas compris?

    No, because they're cop outs. Just accept that quantum physics was, is (and probably ever shall be) a headfuck.
     
  11. Pickman's model

    Pickman's model Poster of the Year 2004

    How are things affected if instead of bob two people called alice are doing the work?
     
  12. Pickman's model

    Pickman's model Poster of the Year 2004

    Magick as we all know is the science and art of causing change to occur in conformity with will.
     
  13. Greebo

    Greebo Laquelle lettre de "non" n'as tu pas compris?

    Pretty please with sugar on it, stop complicating it even more!
     
  14. Greebo

    Greebo Laquelle lettre de "non" n'as tu pas compris?

    Or so Uncle Al said.
     
  15. teqniq

    teqniq DisMembered

    I think it's got something to do with time having no real meaning from a quantum 'perspective'. Everything is/was/will be happening now.

    However I could be/was/am talking total bollox. :)
     
  16. Johnny Canuck3

    Johnny Canuck3 Well-Known Member

    We know so freaking little about almost everything.
     
    xes likes this.
  17. teqniq

    teqniq DisMembered

    So I went to bed thinking 'no that's not right, I meant to say.....' and in fact the above is an edit as I decided the first attempt was inadequate. It would be really great if we had some proper quantum physicists come along and attempt to give a layman's description of what is going on. Anyway haha this maybe more total bollox but say rather that the normal rules that govern how we perceive time in our comfortable day-to-day world no longer apply. This is in part attributable to the concept that matter (that everything is made of) has the properties of both waves and discrete particles. So, if you perform an action on something at point the 'A' the effect can propagate along the wave in more than one direction. From our perspective, into the past or into the future.

    Hopefully someone will come along and point and laugh or put me right. Or something.

    Time, it's just so last year :rolleyes:
     
  18. EastEnder

    EastEnder Brixton Barnacle

    Not sure that's really doable. A layman's description is normally one in which a complex and/or esoteric concept is explained in a simplified form, usually via analogy with more pedestrian concepts. A lot of the weirdness of the quantum world simply cannot be reconciled with the intuitive, macroscopic world in which we live. Trying to find an explanation that seems intuitive, the kind of thing you can picture in your head and go "ahh, yes, that makes more sense now..." is fraught with difficulty. Any such explanation is likely to have to describe things in such a way that the explanation no longer really bears any relation to reality.
     
  19. alsoknownas

    alsoknownas some bloke

    My laymans understanding (which may be deeply flawed, or just plain wrong) is that within a quantum system a [portion of stuff] is neither a wave nor a particle, neither has it a place - rather it is a mere component in a sytem, subject to the laws of probablity.

    It is only when that system comes into contact with another sytem (such as a scientists measuring device), that the wave/particle nature of the entity is resolved, along with it's location.

    But as I say, I could be wrong.
     

Share This Page