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The Quantum World - The Double Slit Experiement

Archie Moses

Archie Moses

Well-Known Member
Is reality real?

https://www.youtube.com/watch?v=DfPeprQ7oGc

I first learned of this the other day while watching Through the Wormhole with none other than Morgan Freeman.

The video above shows scientific proof that there is something NOT quite logical or scientific about this universe. The mere act of observation can completely change the outcome of an event! Before I get too ahead of myself, you need to watch the video below to understand:

(Forgive the corny cartoon character explaining the concept — at least he knows his stuff)

Recap: When a camera observed the electrons, they acted as particles. However, when the no equipment was used to observe the electrons, they acted as waves and particles simultaneously.

So what’s the reason for this? Does the electron somehow know that it is being watched? That was the only “logical” reason that scientists could come up with so much skepticism and controversy followed.
Click to expand...

Then in 2002, a group of researchers set up the experiment in a way that the electron could not possibly receive information about the existence of an observing instrument. The setup was on a much smaller scale: a single photon was emitted and an interferometer that observed the wave-or-particle behavior was either inserted or not inserted. (Click here to download the full report)

Here’s the kicker: The insertion of the interferometer took only 40 nanoseconds (ns) while it would take 160 ns for the information about the configuration to travel from the interferometer to reach the photon before it entered the slits. This means in order for the photon to “know” if it was being watched, that information would have to travel at 4 times the speed of light, which is impossible (the speed of light is the universal speed limit).

The Results: The photons acted like particles 93% of the time that they were observed. Even if the photon “guessed” the configuration each time, statistically speaking it would never have more than 52% accuracy. In scientific experiments, a 93% success rate is as conclusive as they come.
What are the implications of this?

1. Matter can act as both a wave and a particle depending on whether or not it is being observed (Wave-Duality Theory)

This is the least meaningful implication for you as a macroscopic organism, but nonetheless it’s a pretty crazy concept.

2. Observation can (possibly) affect the outcome of macroscopic events

After all, you and everything you know are composed of these microscopic particles, so why couldn’t something large be influenced as well? It would be the sum of a seemingly infinite amount of pieces of matter acting as either waves or particles. Scientists have very mixed opinions on this topic so I’ll just say it makes sense to me that this could happen on a larger scale.

3. We don’t know very much about this universe (Science is not yet an ‘exact science’)

There are a couple things out there that science still cannot explain like the characteristics of gravity, but this blows Newton’s discovery out of the water. As we study smaller and smaller particles in order to understand more about what we’re made, we seem to find more things that just don’t make sense. Point being that nothing should be ruled out completely because we simply cannot know anything for certain at this point.

What other implications did you get out of these experiments?
Click to expand...
 
I know there was some controversy about how this experiment was composed. But I have enjoyed through the wormhole, although it borders on too much to take in at one time.
 
I actually love this show. The episode about "Time" and does it really exist, really made my mind go. The 6th sense episode was $$$ too.

Great show.
 
Good stuff. That is, it's good physics. A lot of times programs like this will simplify things too much and will therefore get the physics wrong.

My only issue with the video clip is that they way oversold the experiment that tested it it. "Physicists were completely baffeld by this!" --> No, physicists had known what would happen since the 1940s. And that particular experiment, in various forms, has been done many times since then. "The quantum world was far more mysterious than they could have imagined." --> No, the experiment confirmed exactly what they predicted.


Archie Moses said:
3. We don’t know very much about this universe (Science is not yet an ‘exact science’)
Click to expand...

I disagree with this statement. Better, would be, "We know enough about the universe to know that Science CANNOT be an ‘exact science’." That is, quantum mechanics doesn't say "We can't make definite predictions of where the electron will land as it passes through the two slits, we can only make predictions about probabilities of where it will land."

For what it's worth, when I was first learning quantum mechanics (as an undergrad back in 1993), I was very skeptical. This particular experiment was one of the things that sold me. It is truly mind-blowing.
 
After trying to watch the BBC documentary on this, this link makes life seem pretty good.

So here's one old-timer's take. Someone who actually understood it in the college course before most JazzFanz folks were born. The way we were taught back then was what the scientists a hundred years ago were figgerin' out. Light is composed of photons, discrete particles with a wave packed right in the tiny little package. And even with a microscopic-sized "slit", something comparable to the actual "size" of a photon, diffraction occurs due to the sharp gradients of electromagnetic field strength in the vicinity of a sharp metal edge. In short, the photon trajectory can be bent passing by an edge of solid material.

I would view it, in quantum mechanical mathematical terms as the "waves within the 'particle' photon" being bent outta shape. But here the single-photon experiment does push our information forward significantly, and the result does force a new interpretation of the nature of a photon. I like the new idea better. Reportedly, it's not just photons that do this with accumulated single-shot experiments. Atoms and even molecules produce the same results. Goes to the way even materials like glass and plastic can produce EMF densities within their materials that cause diffraction. Even a molecule has a helluva EMF within it's "space". With "wave" character. As a high school physics student I even calculated my own "wavelength".

I was a skeptical student way back when anyway. I had a hard time figgerin' how we could git photons to show up for our lenses and do all that wave behavior if'n they wuz just tiny little wave packets in the first place. And I even did an experiment in my basement bedroom when I was in high school. Thinkin' if photons were particles with the speed of light and evin a smidgin of mass, there's gotta be some kinda recoil when they get reflected, like maybe you could measure the force on reflection. So I set up two mirrors as close to parallel as I could and put a lamp sos' I could input a stream of light and just keep reflectin them photons back and forth between the mirrors. Well, after about a day the mirrors broke.

Probably just "heat" did it.

But anyways, as tiny as you might imagine a "photon" to be, it's EMF wave character might not be constrained to the insides of that there little "particle" idea, and the whole mathematics of quantum theory is based on wave functions that would predict photons being "detected" at points where the wave functions give nonzero results. So much for particle trajectories period. I still haven't seen what they used for a detector in these experiments that supposedly changed the behavior of the sensitive self-concious little photons, but I'm bettin it does sompthin to the EMF interference field in the post-slit space.
 
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