Quantum Question

Discussion in 'Physics & Math' started by Roman, Feb 7, 2009.

  1. Roman Banned Banned

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    Question 1:
    If there is a goat behind one of two doors, and I open a door, and there is no goat, does the goat spontaneously come into existence behind the other door?

    Question 2:
    If I have a duck, and I throw it into water, it demonstrates diving behavior. If I instead throw the duck off a building, it demonstrates flying behavior. Does this mean the duck has dualistic flying & swimming properties?
     
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  3. Bishadi Banned Banned

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    Go figure!

    it takes a 'rocket surgeon' to have a sense of humor on QM
     
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  5. Tom2 Registered Senior Member

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    No, but if you weigh the same as a duck then you must be made of wood, in which case you must be a witch.
     
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  7. Roman Banned Banned

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    I'm serious.

    How does not looking at a particle make the particle not exist?

    Entangled electrons going in opposite directions simultaneously determine their spin, which seems pretty incredible. Until you hear about how physicists figured this out. They have two electrons shooting out in different directions, but they don't know which one has up spin and which one down, but they know that one is up and one is down. So they look at one, and suddenly, magically, holy shit, the other one is spinning the opposite way!

    Am I really missing something here?
     
  8. John Connellan Valued Senior Member

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    It is a simple basic truth of nature. There's no point in asking how or why this is the way it is. It is like asking how gravity only acts in one direction whereas the other forces can act in both directions. We have the maths that explain what happens given a certain situation but we don't know why or how
     
  9. Enmos Valued Senior Member

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    No, it means the goat was behind the other door all along, you just opened the wrong door.

    I don't get this one. Do you mean that when you throw it dives and flies both at the same time until you actually look which of the two it is doing ?
    I'd say it is doing one of the two, and you simply won't know which one until you look.. :shrug:
    Although in this case it seems fairly probable that it would not dive if you threw it off a building.
     
  10. Enmos Valued Senior Member

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    Lets say you have two cabins with goat food in them.
    The backs of the cabins have doors that are open.
    Behind the cabins is a meadow with one goat in it.
    You have a computer system hooked up that can tell if the goat is in either cabin, but it cannot tell in which one.
    The moment the goat enters either cabin both doors close and lock.
    After 24 hours you come to the cabins and open one of the two cabins.
    The goat is not there. Does the goat spontaneously come into existence inside the other cabin ?
    You open the other door and the goat is, of course, there.
    But apart from the goat being there, there is also 24 hours worth of goat poo lying on the ground.
    Also, the amount of food that is missing appears to be what a goat would eat in 24 hours.
    So if the goat spontaneously appeared in the other cabin, does that mean that reality quickly winds back
    time and then fast forwards time to the point where you open the door, to recreate all the circumstances inside
    the cabin, so it would look as if it had been there for the past 24 hours ?
    I'm sorry, but this QM shit strikes me as complete nonsense.
     
  11. John Connellan Valued Senior Member

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    But Roman was talking about particles:

    when you get to goats, classical physics take over and so this kind of stuff never happens
     
  12. gluon Banned Banned

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    1) No. In the Copenhagen Interpretation, upon some observation, there either is or is not. If you see no goat, there is no goat.

    2) The duck never decided to be a swimming or a diving expert, so it doesn't really have both properties.
     
  13. Enmos Valued Senior Member

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    I'm pretty sure the OP asked two questions, one about goats and one about ducks.. :shrug:
     
  14. John Connellan Valued Senior Member

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    But you had quoted me and I was referring to the OP's post about particles (if you check what I had quoted)
     
  15. Enmos Valued Senior Member

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    You're right, my bad.

    I'm still skeptical about QM. QM only works with subatomic particles though, right ? Are you knowledgeable in the field ?
     
  16. John Connellan Valued Senior Member

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    I wouldn't say "properties". It has dualistic behaviours alright. I'm sure it has many more at that.
     
  17. John Connellan Valued Senior Member

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    Yes, QM does not work for large collections of particles. Instead, these collections have emergent properties that we call "classical physical laws"

    Not as much as I'd like to be

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  18. Enmos Valued Senior Member

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    But when you say particles you are referring to subatomic particles right ?

    I was hoping you could clarify some stuff for me

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  19. John Connellan Valued Senior Member

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    Atoms themselves can also be influenced by QM laws
     
  20. Roman Banned Banned

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    It seems to me the basic quantum statement is that if we're not "looking", it doesn't exist. Observation, in this case, is the interaction between a particle and our instruments, or interaction with other particles that instruments can measure.

    I fail to see why it MUST be the case that if two particles are in space, why one decides to spin the opposite direction when we observe the other, and until the point of observation, they haven't made up their mind about spinning yet. Note for retards like Enmos- observation merely means the particle interacts with something other than vacuum. Why couldn't they just be spinning in opposite directions the whole time, and we don't know which is up or down, since we haven't looked yet?

    As for ducks:
    Light's specialness doesn't really strike me as all that special. I guess it's because Western science is so infatuated with biconditionals that something that has "dualistic" properties is magical. I blame the Greeks.
     
  21. John Connellan Valued Senior Member

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    It is a consequence of QM being governed by probability laws. The particle cannot be spinning in opposite directions all the time becase either particle may, for example, have an equal probability of spinning in either direction.
     
  22. Enmos Valued Senior Member

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    Roman, you are a dickhead.
     
  23. Crunchy Cat F-in' *meow* baby!!! Valued Senior Member

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    No. The goat was already there.

    No. The duck can distinguish between liquid and gas and chooses an appropriate method of navigating the medium.
     

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