The Double Slit Experiment and Reality

[BMcGilly07]

I don't often have much of an interest in physics or any of the sciences for that matter, beyond a basic understanding of the popular current theories. However I just came across a video explanation of the Double Slit Experiment found on YouTube here: http://www.youtube.com/watch?v=DfPeprQ7oGc.

After reading up on it, I came to a conclusion which may be flawed.

Keep in mind the following facts:

1. Particles have a smallest possible unit before losing their thingness.

2. Multiple particles can be halved and retain their thingness.

3. Particles only add constructively.

4. Multiple waves can add constructively or destructively.

5. A wave can be halved and retain its thingness.

Ergo, via the double slit experiment: Awareness creates order, creates matter, directs possibility into being.

Is this conclusion accurate? Is it the scientific proof that all the world is of the mind? Is it scientific proof that cause and effect is inescapably the driving force of Reality? Or just shoddy thinking?

[kissaki]

The term wave in the context of quantum mechanics is a mathematical construction. No one has ever seen a probability wave move through space. The video is deceptive in that sense.

Also keep in mind that Dr. Quantum is a creation of Fred Alan Wolf, a quantum physicist that writes books on the subject of quantum mechanics explaining consciousness and other spiritual matters. In my opinion the books are shallow and full of fluff and feel-good spiritualism that mentions every kind of spirituality from native American religions to Vedic philosophies.

QM is 99% math and 1% impressive visual demonstrations to be parsed into meaninglessness by the masses.

Edit: Also keep in mind that the mathematics of QM works out the same regardless of whether you interpret it as a wavefunction collapse or a particle riding the probability wave. You either have the math that fits the observed behavior or you don't; everything else is a red herring.

[DHodges]

That video was very misleading.

In particular, "the act of observing" changes the physical structure of the experiment. We are used to being able to look at something without disturbing it; this is not true in the quantum world. You have to bounce e.g. a photon off the electron to see where it is. So the electron does not go on the same path it would have without the "observation;" it is a different experiment. It has nothing to do with some mystical "act of observation." (See more here)

It is (very) misleading to think of an electron as a little marble; the double slit experiment demonstrates clearly that it doesn't act like one. Quantum level entities don't really have good analogs at the macroscopic level. Thinking of them as a particle ('like a marble') or as a wave (in water) is going to be misleading. This is a good part of what makes QM difficult to understand; quanta don't act like things we are used to seeing.

[Shahrazad]

It is (very) misleading to think of an electron as a little marble; the double slit experiment demonstrates clearly that it doesn't act like one. Quantum level entities don't really have good analogs at the macroscopic level. Thinking of them as a particle ('like a marble') or as a wave (in water) is going to be misleading. This is a good part of what makes QM difficult to understand; quanta don't act like things we are used to seeing.

What do you suggest we see them as?

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[brokenhead]

A probability distribution. Right, Hodges?

[maestro]

I would visualize the universe as a unified whole, say a large body of thick fluid.

Matter is a particular configuration of the fluid say lumps in the fluid, which are distinguishable from the surrounding "emptiness", which appears empty because of its uniformity.

The interconnectedness of the fluid ensures that this knot exerts its influence over the whole universe, thus behaving as a wave,

However for certain purposes it can be regarded as a localized entity.

It really matters on how you probe the lump whether it will appear as a localized entity (particle) or a nonlocal entity (a wave).

[kissaki]

You must learn the math to know the full extent of what it is and isn't. It seems everyone wants to get the QM knowledge for free, that is, avoiding the mathematics. Start with the 1 dimensional quantum harmonic oscillator -- easiest QM calculation.

brokenhead,
The probability waves, and waves really just mean complex exponentials, are not 'out there.' They are purely a mathematical construct used to create and test empirical QM predictions.

EDIT: A particle never turns into a wave or vice-versa, nor do constructions such as wavicle make any sense. This is one of, if not the biggest, misconceptions of QM. Energy in QM is always measured in discrete quanta, particles. It is merely that the energy bits influence each other with wave-like characteristics, but the energy manifestation is always discrete. The entire QM edifice was built and is probed with math, the moment you leave it and somehow try to explain what it really is you are only fooling yourself.

[maestro]

You must learn the math to know the full extent of what it is and isn't. It seems everyone wants to get the QM knowledge for free, that is, avoiding the mathematics. Start with the 1 dimensional quantum harmonic oscillator -- easiest QM calculation.

But most physicists avoid visualizing it at all, following Feynman advice "Shut up and compute".

The most popular interpretations are the Copenhagen or many worlds interpretations. These are highly dissatisfying and paradoxical.

Bohm on the other hand was dissatisfied with the "mere computational" paradigm. He went at great lengths to develop a theory of QM consistent with both causality and visualizable. The picture which I have presented follows his interpretation and is far superior to the Copenhagen or Many worlds interpretation (from his book "Wholeness and the implicate order").

Also for anybody puzzled by the apparent paradoxes in QM, it would be good to read this article, which explains that using Bohm's formulation, these paradoxes and puzzles disappear and a very intuitive picture of the world is obtained.

http://plato.stanford.edu/entries/qm-bohm/

Why do then physicists hold on to the paradoxical stuff?
First of all because they were trained by a generation which favored the paradox riddled Copenhagen interpretation, which became deeply entrenched in academia.
And secondly it sounds cool and mysterious and enhances the aura of the field and is useful for gaining publicity (as in documentaries) and funding (from clueless grant managers).

It could also be an egoistical thing to make the field impenetrable to not one of the tribe.

[kissaki]

maestro,

This is what I mentioned in my first post -- regardless of your interpretation the math works out the same. It's always the same pattern on the screen in the double-slit experiment. The whole Bohemian mechanics vs Copenhagen vs many-worlds vs mumbo-jumbo-QM-spirit-world is simply a battle over mind-space as to who gets the bragging rights to the mystery. Which group shall become the next QM priesthood? That's all it is. As far as QM applies to philosophy I think David Quinn nailed it: All appearances of QM are still in the realm of causality and thus not an impediment to enlightenment.

Now on the other hand if you want to construct a new photonic crystal with specific electromagnetic properties, then shut up and do the goddamn math.

[maestro]

This is what I mentioned in my first post -- regardless of your interpretation the math works out the same. It's always the same pattern on the screen in the double-slit experiment.

Hey the math was cooked up to explain the experiments, but yes the prediction are identical irrespective of the interpretation.

As far as QM applies to philosophy I think David Quinn nailed it: All appearances of QM are still in the realm of causality and thus not an impediment to enlightenment.

Oh no not all are causal, for example the Copenhagen interpretation is not causal. This is the reason why many argue that the world is fundamentally random etc. (Victor also had a debate with Quinn on this.)
Bohmian is causal and Many worlds is causal, but in a screwy manner.

Now on the other hand if you want to construct a new photonic crystal with specific electromagnetic properties, then shut up and do the goddamn math.

Of course physics is about measurements and without maths there can be no measurement.

But as Bohm said that without a visualization of the whole thing and just relying on the maths could be a real impediment to understanding and creativity. Lots of physics (including QM) has been advanced through visualization, then modeling and formalization.

[David Quinn]

Why do then physicists hold on to the paradoxical stuff?
First of all because they were trained by a generation which favored the paradox riddled Copenhagen interpretation, which became deeply entrenched in academia.
And secondly it sounds cool and mysterious and enhances the aura of the field and is useful for gaining publicity (as in documentaries) and funding (from clueless grant managers).

It could also be an egoistical thing to make the field impenetrable to not one of the tribe.

That's pretty much spot on, maestro.

You might be interested in some of the thoughts aired on a physics forum that I had briefly joined a few years ago: Quantum Theory and Causation

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[kissaki]

maestro,

The QM interpretations themselves are completely within the realm causality, regardless of whatever fanciful imaginations are involved in it. You're basically saying, oh the universe is non-causal because I can concoct a theory in my head that says it's non-causal ... without providing any kind of physical evidence of this non-causality of course. The fact remains that every single manifestation of QM is consistent and repeatable -- every time. We can't see how it all happens but we sure like to imagine what we might see. All we know is that the math works, we don't know why, and we don't even know if the math we are using is in any way shape or form representative of what is really happening, whatever that might be.

Visualizations are a useful scientific tool, no debate there. However, visualizations are never complete substitutions especially when dealing with high-level math involving infinite vector spaces. The hilarity of it all is that infinite vector spaces provide infinite ways of visualizations, and thus a playground for scientists to let their artistic imaginations run wild.

I'll make it easy: Show me an example of a probability wavefunction in action in the empirical world and I'll revoke every word I've said on this matter.

[brokenhead]

brokenhead,
The probability waves, and waves really just mean complex exponentials, are not 'out there.' They are purely a mathematical construct used to create and test empirical QM predictions.

Yes, I know that the waves are not out there but rather "in here." My BS degree was in physics so I did learn the math, albeit some years ago.

[maestro]

The fact remains that every single manifestation of QM is consistent and repeatable -- every time.

No, we do not know when an individual atom will decay for example, the consistency is only in the statistics.

I'll make it easy: Show me an example of a probability wavefunction in action in the empirical world and I'll revoke every word I've said on this matter.

How about Schrodinger's cat experiment which magnifies the effect of the randomness in subatomic particles to the macro level.

You're basically saying, oh the universe is non-causal because I can concoct a theory in my head that says it's non-causal

Non-causality is a superset of causality, so I do not see any reason to lose so many degrees of freedom so hastily.

[kissaki]

No, we do not know when an individual atom will decay for example, the consistency is only in the statistics.

Which only means we currently don't have a way of knowing when a particular individual atom will decay. Not knowing does not automatically imply non-causality. We may possibly may never know.

And only the statistics? You wouldn't even know definitively about the existence of atoms if it weren't for only the statistics. You have no other way of seeing or knowing atoms. If you want to invoke magic then simply claim invocation of magic, don't criticize the only tool which has gotten us this far into empirical knowledge and then leave some vague opening for the possibility of knowing all this through some other undefined means.

How about Schrodinger's cat experiment which magnifies the effect of the randomness in subatomic particles to the macro level.

It's a thought experiment and remains as only a thought experiment to this day. Besides, the moment you look in the box the probability wavefunction collapses according to the Copenhagen interpretation. Even then you never observe the wavefunction itself. It exists only as a construction of thought.

Non-causality is a superset of causality, so I do not see any reason to lose so many degrees of freedom so hastily.

You have no basis for saying this. Nearly all appearances we know have shown themselves to be causal in nature, and the ones that are undetermined are simply undetermined. Again, not knowing does not imply non-causality. Claiming otherwise is magical thinking. Your stance seems similar to the God of The Gaps Theory, except yours should be called Non-Causality of the Gaps Theory.

EDIT: Furthermore, QM does not claim to predict the exact behavior of a quantum particle. So to suggest that the inability to do so is somehow a counter-example to the consistent statistical predictions of QM is disingenuous. QM is completely consistent. If a technique is ever created to predict the exact behavior of a quantum particle then it will be incorporated into QM and QM will remain consistent.

[DHodges]

It is (very) misleading to think of an electron as a little marble; the double slit experiment demonstrates clearly that it doesn't act like one. Quantum level entities don't really have good analogs at the macroscopic level. Thinking of them as a particle ('like a marble') or as a wave (in water) is going to be misleading. This is a good part of what makes QM difficult to understand; quanta don't act like things we are used to seeing.

What do you suggest we see them as?

I suggest that any simple view or analogy is going to be misleading.

A probability distribution. Right, Hodges?

The probability distribution allows you to predict some of the behavior, but does it really tell you what it is the behavior of? It doesn't really give you much understanding of the underlying whatever-it-is.

[DHodges]

QM is completely consistent. If a technique is ever created to predict the exact behavior of a quantum particle then it will be incorporated into QM and QM will remain consistent.

And yet, if I remember correctly, QM is not consistent with relativity.

(Or perhaps it has just not been shown to be consistent.)

[kissaki]

QM is completely consistent. If a technique is ever created to predict the exact behavior of a quantum particle then it will be incorporated into QM and QM will remain consistent.

And yet, if I remember correctly, QM is not consistent with relativity.

(Or perhaps it has just not been shown to be consistent.)

Yes I could have been more specific in my statement. QM in and of itself is a consistent theory. Making QM consistent with GR across all energy spectrums is still the problem worth all the marbles.

[David Quinn]

Non-causality is a superset of causality, so I do not see any reason to lose so many degrees of freedom so hastily.

Again, the restrictions you see in causality are not really there. You're chasing a phantom of your own making.

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[maestro]

Again, the restrictions you see in causality are not really there. You're chasing a phantom of your own making.

The restrictions are quite severe, not an ounce of freedom from the past. Like the past the future is frozen solid.

[Diebert van Rhijn]

Again, the restrictions you see in causality are not really there. You're chasing a phantom of your own making.

The restrictions are quite severe, not an ounce of freedom from the past. Like the past the future is frozen solid.

That restriction is only relevant from the position of an omniscient being which you are I are not. The moment one misses the knowledge of even only a few causes, one ends up knowing nothing empirically for certain at all and the future could as well be called totally open from that perspective.

[David Quinn]

Again, the restrictions you see in causality are not really there. You're chasing a phantom of your own making.

The restrictions are quite severe, not an ounce of freedom from the past.

Yet it is free to create everything that we experience in each moment. It creates our very lives. That not good enough for you?

There is no freedom in uncaused events, only nonsense. An uncaused act is an act which lacks context, which immediately renders it into nonsense.

Like the past the future is frozen solid.

Future cannot help but be frozen solid, regardless of any other consideration. Whatever happens, from whatever process, will instantly be solidified. Nothing we can do about that.

So by my count, that's at least two phantoms you are chasing. And for what purpose?

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[maestro]

That restriction is only relevant from the position of an omniscient being which you are I are not. The moment one misses the knowledge of even only a few causes, one ends up knowing nothing empirically for certain at all and the future could as well be called totally open from that perspective.

If acausality is true then omniscience is also impossible, since the future is undecided. It means that our perspective is also the universe's perspective, and the universe is unfolding with us, rather than it being frozen and we being artifacts.

An uncaused act is an act which lacks context, which immediately renders it into nonsense.

How about a power (akin to free will) to choose one course of action another, it is not nonsense.

Future cannot help but be frozen solid, regardless of any other consideration. Whatever happens, from whatever process, will instantly be solidified. Nothing we can do about that.

As I said to Diebert that if acausality is possible then the universe is evolving with us rather than being a four dimensional fixed block, so the future is not frozen solid, and the present has a special significance in which possiblities are chosen.

[Jamesh]

As everything is causal then, regardless of how we actually observe things, in reality every thing must exist in wavelike form. A cause cannot be a cause unless it has a holistic or wavelike action - that is, it must affect and be affected non-linearly (mind you the term non-linear must by default include all possible linear observations - linear observations are effects, they are what we refer to as things)

Particalisation is simply those parts of the universe where equality produces increased staticness relative to what surrounds the equalisation.

[David Quinn]

That restriction is only relevant from the position of an omniscient being which you are I are not. The moment one misses the knowledge of even only a few causes, one ends up knowing nothing empirically for certain at all and the future could as well be called totally open from that perspective.

If acausality is true then omniscience is also impossible, since the future is undecided. It means that our perspective is also the universe's perspective, and the universe is unfolding with us, rather than it being frozen and we being artifacts.

Omniscience is just as impossible in a deterministic universe, which cannot help but unfold and evolve in each moment.

An uncaused act is an act which lacks context, which immediately renders it into nonsense.

How about a power (akin to free will) to choose one course of action another, it is not nonsense.

The act of choosing is necessarily a causal process. It involves weighing up information and making a judgment based on one's experiences, reasonings, mood, values and goals.

By the same token, the act of choosing is incompatible with the acausal act of things just happening out of the blue. Acausality is blind and random by nature. The decisions our minds "make" would have nothing to do with us if they were acausal.

Future cannot help but be frozen solid, regardless of any other consideration. Whatever happens, from whatever process, will instantly be solidified. Nothing we can do about that.

As I said to Diebert that if acausality is possible then the universe is evolving with us rather than being a four dimensional fixed block, so the future is not frozen solid, and the present has a special significance in which possiblities are chosen.

Evolution is a causal process, involving incremental development of what is already there. It is infinitely more likely that random, acausal acts would hinder the evolution of things than help it.

I think you have a psychological aversion to causality - partly caused by a misunderstanding of it (equating it to a rigid universe), and partly because it exposes our empty nature, a reality that the ego tends to equate with death.

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