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The meaning of double slit experiment

  1. Jul 4, 2013 #1
    The meaning of double slit experiment....

    As i understand the outcome of the double slit experiment is firstly the Photons of light that were fired have no true location and seem to jump about and interact with themselfs. So my question to that is, have they tried anything bigger than a Photon? Would/can something of a greater mass leap/jump and interact with itself? Whats to say anything or anyone could suddenly leap jump shift or whatever to anywhere else in the universe???????

    My next question about this experiment is...as i gather the photons acted differently when they were monitered going the the slits. So the simple act of trying to record and witness physics at this level can determine the way in which it acts? So im just wondering, whats really going on??? whats happens when were not observing anything? To me i found myself asking the age old question......Does a falling tree really make a sound if noone is there to here it.....or infact is it there at all? May sound silly but does anyone get what im trying to say here????

    Does anyone have any further infomation or views on this?
  2. jcsd
  3. Jul 4, 2013 #2
    It is more than that. If the "physics at this level" can be recorded and/or witnessed, then this is the way it acts. Or better, if this is the way it acts, the physics can be recorded. If it acts in other way, then it cant be recorded. It doesnot matter weather you see the meter/reading or not (nature behaves as she should and it doesnt depend on you or me seeing the reading etc).

    Of course there is a well developed theory (on solid mathematics) known as Quantum Mechanics.

    To be frank no one knows (AFAIK). Hence the interpretation problem of Quantum Mechanics.
    Well in this case if you apply the logic I stated, you will see that the production of sound doesnot depend on the presence of someone. Nature behaves as she should, and hence the sound is made because on collision the vibrations are produced in air :)
    Last edited: Jul 4, 2013
  4. Jul 4, 2013 #3


    Staff: Mentor

    Yea they have - do a search on Buckyballs. In more recent times however its become obvious since everything is quantum something must be responsible for the world of everyday experience which most definitely does NOT behave that way. What we now know is its not a matter of size, its a matter of objects getting entangled with and interacting with the environment. Its very difficult to isolate objects from the environment - it requires temperatures near absolute zero for instance - but when you do that quantum effects assert themselves even for macro sized objects and you get some very very weird behavior. Look up Bose Einstein Condensates and Liquid Helium.

    Quantum Mechanics is a theory about observations on a system - what is happening between observations the theory is silent about. The reason we don't notice this in everyday life is everything is constantly being observed by the environment. Einstein once said to Bohr - "I, at any rate, am convinced that He (God) does not throw dice." and "Do you really think the moon isn't there if you aren't looking at it?" Bohr, in response, said, "Einstein, don't tell God what to do."

    The joke is they were both wrong - the moon is there when you are not looking because it is being constantly observed by its environment eg photons from the sun. And while it is generally thought Einstein lost the debates with Einstein it is now known Bohr's ideas were deeply flawed - not in the sense they were actually wrong - but had a dirty great big gap. Steven Weinberg expressed it thus:

    'A'll this familiar story is true, but it leaves out an irony. Bohr's version of quantum mechanics was deeply flawed, but not for the reason Einstein thought. The Copenhagen interpretation describes what happens when an observer makes a measurement, but the observer and the act of measurement are themselves treated classically. This is surely wrong: Physicists and their apparatus must be governed by the same quantum mechanical rules that govern everything else in the universe. But these rules are expressed in terms of a wave function (or, more precisely, a state vector) that evolves in a perfectly deterministic way. So where do the probabilistic rules of the Copenhagen interpretation come from? Considerable progress has been made in recent years toward the resolution of the problem, which I cannot go into here. It is enough to say that neither Bohr nor Einstein had focused on the real problem with quantum mechanics. The Copenhagen rules clearly work, so they have to be accepted. But this leaves the task of explaining them by applying the deterministic equation for the evolution of the wave function, the Schrodinger equation, to observers and their apparatus.'

    And I will have to leave it at that. If you would like to join us and delve into the detail yourself a new book has appeared that will be a great help:

    Its about Classical - not Quantum Mechanics. But it gives the required background to start to understand the literature that will allow you to make sense of this stuff. Take your time and you will enjoy a wonderful journey.

  5. Jul 4, 2013 #4


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    Buckyballs are molecules of Carbon 60, ie 60 atoms! Everything technically has both wave and particle elements, although bigger things tend to appear as definite objects and smaller seem somewhat more like waves.
  6. Jul 4, 2013 #5
    bhobba (bill) thanks for your reply it was alot of help infact all the comments were. I think your rite though bill its something i really need to study further to even begin to try and get my head round. Im a 26 year aerospace engineer and have only just began being, to be honest, stunned by how fasinating all these subjects are.................
  7. Jul 4, 2013 #6

    The biggest problem is with objectivity. Quantum systems, as seen in your experiment, display contextual properties, hence all interpretations can provide only contextual objectivity. And at our level of scales nothing at all seems contextual in any way or form. :confused:
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