Current Explanations of Quantum Mechanics

[Ghost Post]

A really good chapter explaining this is in the book, Paradigms Lost. I forget the author, but check Amazon, I believe the publishing year was 1991. The author spends each chapter on current thinking on a particular problem in science, and gives the current thinking on how to resolve them. The Minotaur himself recommended this book to me.

The problem is this:
Quantum Mechanics work. Plug in numbers to the formulas, and everything just comes out right. But why should the universe (or the multiverse) behave in this really odd way.

There are 9 different explanations given in Paradigms Lost that all are mathematically equivalent, but are entirely at odds with one another. I'm sure there are more.

The Standard Model (Copenhagen) comes right from Dirac/Heisenberg/Bohr/most everyone else who developed those magical formulas mentioned earlier. The belief goes like this:
Anytime a particle/wave is not being acted upon (the word "observed" was really just a bad translation from German) by any other particles/waves (good luck pinning this definition down) it goes into a superposition of all possible states until it is acted upon again and then chooses at random one these states that is mathematically allowed.

The Copenhagen Explanation:
The photon passes through the slits. The photons could have passed through the slits in two major ways, as a wave or as a particle, so on the other side the photons are in the superposition of all of these two types of states. Flat boards tend to show off the waviness of the superpositions, so you see a diffraction pattern. Detectors that are positioned such that they can only see photons that went through one side tend to cause these superpositions to collapse into these type of particle states.

This would be how most physicists would explain the double-slit. The photon went through both as a particle and a wave, and your choice of how you decide to measure those photons will give you the result you're looking for. By using a detector you seem to be changing events back in time, but this is not what's going on according to the Standard Model.

Feynmann had another explanation. He didn't like this explanation at all. One of the things he noticed was that from a mathematical point of view anti-matter is merely matter going backwards in time. This explains why there is no anti-matter in the universe by saying that none is being created in the future. No Big-Crunch, universe flat or expanding, etc. This may not be correct with some current experiments showing that anti-matter is in fact a bit less stable than matter. Not terribly important for this discussion. He just extended this thinking to say that at every quatum event, some information was sent back in time to previous events. By setting up a particluar detector you are are sending information back in time forcing the photon through one of the slits or through both. Again, when you set up the experiment you pollute it.

These explanations are ugly and you really have to stretch to explain some other experiments. Read about cosmic inflation to see hacks upon hacks to get fairly elegant theories to explain reality.

There's a theory that's growing in popularity that sheds all of these hacks, by saying this: Everytime a quantum event occurs an infinite number of universes are spawned. Through a clever mathematical construct called a Hilbert Space you don't even need to violate Conservation of Mass and Energy either. The model is alternatively referred to as Everett (invented it) or the Multiple Universes. A good physicist friend refers to it as the worst violation of Occam's Razor that he has ever heard of.

Everett's explanation for the two-slit experiment would be that when you use a flat detector you're in one universe and the photons travelled through the slits as waves, while when you use a photon-beam detector, you're in a universe that the photons went through as particles. Unrelated to this problem, cosmic inflation and omega equalling one make perfect sense.

The downside to this theory is that you may as well explain all the dark matter to a alien race's undetectable stash of spare bowling balls.

The reasoning for this goes:

1) Science doesn't answer questions that can't be measured through experimental evidence.

2) You can't measure these other universes.

Q.E.D. This isn't science.

It's not quite this bad, due to some current theories that you CAN measure these universes when they are just starting to form. I don't believe you should trust any experiment done in the last 5 years. There hasn't been enough time for alternate explanations to be put forward, but if you are interested, search the 'net for pages on Quantum Computing. They're all Everett proponents.

None of the rest of theories interest me in the slightest.

My opinion:
Feynmann from my Physics/Math background.
Everett when I'm in a Sci-Fi mood.

My prediction:
All of these will be wrong. Something even weirder will come along in a few years. The quanta just seem to like doing that to us.

[AcidFast]

Thank you for that, Ark. That was very interesting. I agree with you on a few points:
#1 None of the rest of the theories interest me in the slightest. Actually, except for the one someone mentioned about quanta being 4-or-more-dimensional, and we being three dimensional can't observe it fully. But the rest of them sound like philosophy to me, not science.

#2 All of these will be wrong. Call it Occam's Razor, or call it a 'gut feeling' (which I am in the habit of going with more often than not), but none of them sits right with me. Can't fully explain it, can't put my finger on it, but I am convinced none of them are correct (fully, at least).

However, I still do think that, one day, science will evolve to a point where whatever explanation is finally proven for this phenomenon will be one that 'sits well' with people. In other words, I believe that there IS an explanation out there that, if not today, then someday, will be easily conceivable by the human mind.

So far, I do not feel that any of these explanations meet the above criteria, and although I can't prove any of them wrong (I wouldn't even know where to begin), they disturb me.

Was it Feynman who said he wished he never got involved in Quantum Physics in the first place? I can't remember.

[Ghost Post]

1) Sorry for starting this in a new thread. I didn't understand the interface of UBB. As a possible suggestion, maybe you should only be able to reply when viewing articles and create new forums when looking at the current forums. Just a thought.

2) I should have mentioned that the author of Paradigms Lost came to the same opinions as me, but I had already made up my mind before I read that last few pages. I'm not just blindly agreeing with him.

I believe that we might not understand the "right" explanation, but my gut reaction is that the multiple dimensions isn't the root of the problem. I don't have too much of a problem with 4-space. The String/SuperString/Membrane theories of the fabric of space with >10 dimensions, I'll probably never get, especially multiple time dimensions.

The author of Paradigms Lost gives a more basic problem. Everything we are taught about basic Boolean logic do not apply at the quanta level. Take for example this:

A & <anything else> & ~A = Empty Set

Or, in English, any set intersected with the inverse of that set, intersected with anything else is ALWAYS the empty set. Intersection and Union commute, too. i.e.

A & B = B & A

So, if you have a filter that only allows up-down polarized light through, and add a filter behind it that only allows right-left polarized light through it, it won't matter what's between them, no light can get through, right?

Wrong.

| + / + - = a very little light polarized left-right.

Even worse, from a macrocosom point of view, that '+' sign doesn't commute.

| + - + {anything at all} = no light

Our most basic rules of how things behave in the world that we can touch and see just do not apply at the very small scale. We may be the only block left to putting all of the experiments together. That's how I see it anyways.

[Ghost Post]

reading books written for the general public on physics,(for the layman) can be interesting, but often leave the reader with a far too simplified model of the situation.
i have experienced going from reading these texts to then studying physics, and i would advise against deciding between different theories based on what you have read in them.

many of the theories have to be discussed in such superficial terms that the reader does not understand their implication or power.

often these theories arise because of problems in the other theories which are too subtle or mathmatical for a laypersons book to delve into.

occams razor is a nice principal, but un-appliable unless you really do understand all the factors involved.
ie. ppl who refuse to study science might consider the earth as the centre of the universe for its "simplicity"

[Amy]

If they refuse to study *any* science, including astronomy, then it doesn't matter whether they consider the earth to be the center of the universe. It only matters when you are trying to apply that model to something. People who "refuse to study science" don't have to apply it. For those of us who do, however, a heliocentric model is more useful.

As my friend's physics teacher used to say: "Models are not accurate or inaccurate. They are more or less elegant."

[Ghost Post]

Hi,
I'm Arkamedes' friend who mentioned Occam's Razor in offline discussions of the Many Worlds interpretation. I've got three responses to boom's message...

(1) I agree that attempting to decide between conflicting physical theories based on lay texts can leads to trouble. At best, you adopt the author's spin on the subject, even if the author is attempting to be neutral. At worst, you make a choice at random. That's why I wasn't relying on popular texts as my sources, but rather, on my education (M.S., physics). Oops, I mean, "Mortal, I am Urania, the Muse of Astronomy, so I know whereof I speak "

(2) I like Occam's Razor, but I only use it to make "zeroeth-order guesses." If I don't have enough data to decide between alternatives, I resort to Occam to make my initial guess. Of course, further observation may prove that guess wrong. At which time, I modify the existing theories such that they satisfy observation, and apply Occam again...

(3) Actually, the form of the heliocentric model that accounts for the state-of -the art Middle-ages observations is *less* complicated than the geocentric model. In order to account for the retrograde motion of the planets, supporters of the geocentric model had to introduce epicycles. The heliocentric model accounts for the observed phenomena as well as the geocentric, without introducing epicycles. Therefore, the heliocentric model wins the Occam's Razor argument. Of course, that's not "proof" that heliocentric is correct, but I think that it makes it more likely.

PS For Amy: I think that "simplicity" is a big part of "elegance," so I guess that I agree with your friend's teacher, too.

[This message has been edited by Urania (edited 01-09-2000).]

[Chaodyn]

My entire problem with explinations of quantum physics is this: we are basing our models and theories on prinicples measured in a laboratory. This was fine at first, because we were measuring large things like apples falling in gravity. Now we are at an age where we are trying to measure quantum events with instruments that in my opinion are not suited for the job. How can you measure something accuratly moving at the speed of light with an instrument that takes samples and gives results at the speed of light? Isn't that like trying to measure the speed of sound and what's happening to a supersonic aircraft with an instrument that can only read and report at the speed of sound?

I personally don't think there is a universal speed limit (c), mainly because of gravity. It hasn't been explained by quantum physics and might never be. Might this be because all we can measure is the speed of light, and maybe gravity falls beyond our ability to measure? Hmm...

[Ghost Post]

chaodyn:
i am not sure what point you are trying to make but i think you are underestimating the inginuity of physicists. you do not have to "give results at the speed of light"... results can be combined and conclusions drawn at any later time or date.

on the subject of occams razor, i think what some ppl miss sometimes is that the proposed model does not only have to be simple.. but also must satisfy the requirements of the problem at hand.
i think that all the religious and spiritual crap floating around has somehow led ppl to believe that our conciousness is not something that is a result of the physical universe. so they dont look to explain it in their models, and by occams razor feel confident in models with much less sophistication than the universe really has.
n oone really knows how the mechanisms of the brain create consiousness, but i would bet everything i have that if you understood that process, you could prove that it is impossible to come about in a deterministic universe. otherwise you could make all kinds of contradictions about knowing the future then changing it and it would not be self consistent.

so many ppl do anything they can to try and explain the uncertenties of quantum physics with underlying determenistic models, but before trying to simplfy the solution, they should make sure they are not simplyfying the problem.

so i challenge occams razor with the anthropotic principle (think i spelt that wrong)

[Andy]

Boom - you make a good point. The wording of Occam's Razor that I first saw was something like this:
"Of two explanations that fit the observed data equally well, the simpler is to be preferred."
Obviously this rules out simplification of the problem. It may be reasonable at times to ignore the data we can't explain - but it isn't Occam's Razor (unless no more fitting explanation is known).

Anthropocentric principle?

[Ghost Post]

anthropotic principle:

"it is that way, because if it wasnt, then we wouldnt be here to see it"

may seem kind of obvious at first but i think it is a very important principle. it is generaly usaed to explain why the universe is so stable and why conditions for life are so un-explainably perfect.

eg: for ppl who think relativity could easily not exist and human life wouldnt be affected, there are some particles created in the upper atmosphere by cosmic rays with half-lives far too short to make it to the earths surface, but due to their speed and relativistic effects they make it to the surface and are thought to play an important part in causing biological mutations

why is the world relativistic?
if it wasnt we would be here to see it

[Ghost Post]

Actually, boom, I think that we're agreeing on the application of Occam's Razor. It should ONLY be applied to theories that explain the available facts. Theories that don't (mostly) do so "don't get to play the Occam game."

So to go back to the heliocentric/geocentric example, the only geocentric model that explained retrograde motion had epicycles and other, um, "enhancements" to explain the observational data. If a medieval philosopher steped back and compared (a geocentric model sufficient to explain the observations) to (a heliocentric model suficient to explain the observations), then he would have seen that that heliocentric model was less complicated than that geocentric model. So he should have "bet" on the heliocentric model. And he would have been correct.

One other thing; while I am serious in my belief that multiple worlds is just too complicated compared to other comparable theories, there was a bit of a joke going on, as well. In my original discssion with Arkamedes, we happened to mention William of Occam's original definition, which referred to "avoiding a multiplication of entities" (or words to that effect). Well, creating *several entirely new universes* for every single quantum event struck me as the biggest "multiplication of entities" that there could possibly be. Yes, I know, Occam was talking about "features of a theory" when he said "entities." But if one applies a slightly different spin to that definition, then I think anyone with a sense of humor has to agree that multiple worlds is the *greatest* violation of Occam's Razor ever conceived

[Ghost Post]

Urainia: i know we are, i just think that most ppl diregard the existance of sentient beings as an important fact to explain. otherwise they wouldnt be holding so dearly to their deterministic models.

my problem with multiple worlds is that any finite possibility of worlds is unable to account for all the probabilities. there would need to be infinite... created at each instance of time... all seems a bit too much.
also that at any instance.. trillions of quantum events are happening, all with their own complicated probabilities.. so in order to figure out the states of all the new universes would require some enourmous data collection calculating machine external to the universe. (and you'd have to define a reference frame for "instance of time")
i think the universe propogates itself without any external help