Multiple Slit Experiment?

Thanks Joshi

Just what I needed.

That will keep me busy for a while

Yes
Del

(don't forget to click the GA box folks)

All of those experiments end up supporting the same conclusions:

That photons act as both a particle and as a wave depending on whether there is an "observer" or not.

"Now I see!" ,said the blind carpenter as he picked up his hammer and saw.

Thanks everyone!

These 'Holiday Specs' use 'holograms' to create images around the lights on a Christmas Tree (or any pinpoint light source). The lenses are actually special types of diffraction gratings, which are versions of multiple slits in 2 dimensions. They actually work really well. I bought a few pairs a number of years as little surprises for my wife and son one Christmas morning.

http://www.holidayspecs.com/index.php?option=com_content&view=article&id=1&Itemid=2

So why cant it be defined as waves OF particles?

Some call them wavelets, but think about a single photon that has both wave-like and particle attributes.

In your analogy of a single particle you really can not create a wave. You need many. Just like a sound wave is a collection of air molecules of varying densities rippling across the room.

The concept of a photon wave is really considered a probability wave in quantum physics. Heisenberg stated that we can know a particle's velocity or its position with great accuracy, but not both.

The probability wave tells us with greater or lessor probability where a particle may be found at any given time, but not with any certainty. The same thing applies to an electron orbiting a nucleus. We have a probability where it will be found and we have places where the probability is nil, such as when an electron transitions from one orbital shell to another.

The "collapse" of a probability wave it the point where the wave function of a particle's vector becomes certain as a particle or in the case of a detected photon.

The point of collapse seems to be the point where we consciously observe or interact with the wave function.

You can apply this, with some caution, to the macro world and ask does the Moon exist with no eyes to see it? In the world of quantum physics the answer is, no because all particles that make up the Moon are simply a probability wave at that unobserved instant.

Confused yet?

One of the reasons I like the idea of string theory (though I admit I know almost nothing of the math) is the idea that a particle could be a tiny piece of vibrating string. Thus it has a sense of location like a particle, yet can also have a frequency and a wavelength. It can vibrate open-ended, or it can be closed up like a toroid.

Ok, back to a question I asked quite a while back in a different discussion:

If observation by a consciousness is required for existence of anything, then what "Observer" made us "Real", if indeed we are real.

We cannot know anything without observing it via one or more of our senses.So if we do not observe it, for us it does not exist.That is subjective reality.

A person under the influence of drugs is convinced he can fly, and as he leaps from the top of the building, he is indeed flying.At the point that he impacts the sidewalk, the probability wave collapses, and so does the subjective reality.When objective and subjective reality collide, objective reality always loses.

Saying that something is altered by observing it is true, but only in our realm of experience.The object was what it was before we observed it.We are always observing the past.We can never observe the present.Light requires a certain travel time from the object to the observer, so what we see,or observe, is a past event.Similar to looking at the night sky, but on a smaller scale.

A photon travels at the speed of light, which, according to Einstein, is where time stands still.There is plenty of time at that speed to appear in more that one place at the same "Time".

"Spooky action at a distance" opens the door for lots of "spooky" things to happen faster than "C".We just would not be able to observe them,because information cannot travel faster that light.

I believe spooky action occurs at many places besides with entangled particles.

IMHO.

Yeah, that whole idea that reality requires an observer always sounded like a lot of hooey to me when I took QM in college. It just didn't sound scientific.

A few years back I read one of Roger Penrose's books in which he proposed an alternate to this part of the Copenhagen Interpretation. Makes a bit more sense to me. Here's a Wiki link to his idea:

http://en.wikipedia.org/wiki/Penrose_interpretation

THAT observer is called the "Grand Observer". The next question that arises is usually "Where is he?"

The answer is relative. Where is the questioner?

The answer to this is, "Within"

The only answer that makes any sense is that the GD is looking within and what we see as reality and substance, and particles is what is observed there. In other words, the whole shebang is within the only observational space that is guaranteed to yield a result for the GD, assuming the GD is consciousness. We cannot know what is without the GD, and He can only know what is without if he has a reference point for the opposite condition as a basis of observation and comparison. However, if he is conscious, even within a void, he knows of himself in general, if not in detail, and can therefore look inward and be guaranteed a result.

Same is true for any self with that grand self.

So, Buddha mind, here I come!

How easy it is to strangle on a gnat, yet swallow a whole camel.

AH,

I've read a number of books on Quantum Theory, but I don't claim to be an expert by any means. Here are a some of my thoughts.

From my experience, if something doesn't make sense, we've made a bad assumption somewhere, or we're not seeing the whole picture, so to the blind man, the elephant seems like a rope, tree, etc (you recall the metaphor).

A light wave acts like a particle and a particle (say an electron) acts like a wave. But a light wave is different from a probability wave in that it has an oscillating magnetic and electric field associated with it. Most of what I read seems to group these two together. So maybe light just interacts with matter in this strange way (energy proportional to frequency) and these are just two phenomena that look similar and don't represent some particle-wave equivalence.

As a particle moves it has wave like properties. Is it possible that as it moves, it somehow rotates into another dimension (possibly one of those rolled up dimensions), so that it is only periodically in existence in our 3D plane where it can interact with other particles that are doing the same thing? That would let it be a particle but act as a wave.

I'm very troubled with the 'Consciousness' thing. I feel that the only thing Counsciousness and QT have in common is that nobody really understands either.

If I remember correctly, when experiments with two or more diffraction slits have been performed where statistically there is only one photon in the system at a time the multi-slit diffraction pattern still appears! This seems to indicate that the single photon went through multiple slots simultaneously...... very strange!

What if the photon is actually a "droplet" of energy that splits when it hits the boundary between slits.The total energy delivered is not double the input energy, so it must be dividing at some point.

If the accumulated energy is double the total, then they must be created at different times to give the same power as a single slit.

Try putting a double slit in front of a single slit and see what happens.Will the wave revert back to a particle?Or try just the opposite configuration.I am sure someone has tried this, and I wonder about the results.

How about a target screen that is a parabolic reflector with the focus back to the slit?

With proper spacing and focus it should be possible to cancel all incoming photons at the slit boundary, with a slight delay.A divide by 2 counter?

Just curious.

Interesting thoughts

Yeah, there's that non-locality thing. These puzzles go away if you consider light as an electromagnetic wave, but then you have to figure out why it interacts with matter in quantum chunks.

I guess the reason it makes no sense is that it's like nothing we have any experience with. That's still not very satisfying.

Have a look at gratings

gratings search

Look at high school physics text books

Yes the double slit experiment is sometimes called Young's Experiment wherein matter and energy can display characterstics of both wave and particles.

With regard to only part of your question, the wave and particle do not "separate." Instead, the particle appears when one observes it, and the wave gives the probability of such an observation at any given place.