Quantum mechanics and randomness

[arkajad]

dBB has less predictive power than standard qm.

Which should not be a surprise taking into account how much has been invested in the standard qm and how little in the alternatives. You will say that people invest in what is good and do not invest in what is not so good? Well, look what happens to many real investors - after a crash they say (if they do not commit suicides): Oh, I should have invested in something else...

 

[ThomasT]

The problem is that I seem to hear that "quantum" randomness has nothing to do with our ignorance of the variables involved ...

Then you're hearing it incorrectly. Quantum randomness has everything to do with physicists' ignorance of the variables involved. Why do you think that qm is a probability theory? It's because physicists don't know what's happening in the reality that underlies instrumental behavior. They're probing this underlying reality in a more or less random, haphazard way. And then they're making some inferences regarding these probings, and fornalizing some of them, and then doing more, more or less random haphazard, probings. It isn't an exact science. It's probabilities based on the behavior of detection devices. That's all there is.

 

[arkajad]

@ThomasT
But it is also possible that even knowing all the variables involved a given process can still be considered as random - simply because of its complexity - you will never have the computing power to calculate the result within a given error margin. Still you may be able to use probability theory in such a case.

 

[ThomasT]

Which should not be a surprise taking into account how much has been invested in the standard qm and how little in the alternatives. You will say that people invest in what is good and do not invest in what is not so good? Well, look what happens to many real investors - after a crash they say (if they do not commit suicides): Oh, I should have invested in something else...

Well, the best minds in physics have decided to endorse standard qm, which means that they endorse the Born-Copenhagen interpretation. And from what I know of qm, this is the most sensible way to think about it.

 

[ThomasT]

@ThomasT
But it is also possible that even knowing all the variables involved a given process can still be considered as random - simply because of its complexity - you will never have the computing power to calculate the result within a given error margin. Still you may be able to use probability theory in such a case.

Well I can't argue against this.

 

[ThomasT]

By the way, arkajad, you write very good English. Better than me really. I'm impressed but not really surprised. I've looked over some of your publications and I can honestly say that I don't think I'm qualified to even begin to understand any of them. So, whatever you say about pretty much anything I think I have to defer to your judgement.

 

[wuliheron]

You can't predict the outcome of a complex deterministic machine when it it goes through a certain number of iterations. There is absolutely nothing particular about quantum randomness that would distinguish it, by objective tests, form sufficiently complex deterministic schemes. What is amazing in quantum theory is its apparent nonlocality of computation, not its "randomness".

You can turn your own argument on its head and say that there is nothing to distinguish the supposidly deterministic from the random. Just because I roll the dice six times and get snake eyes every time does not mean the dice are loaded in some sort of metaphysical sense. All it means is that I observe what we could call order. Thus we use the convenient fiction that we "know" something is a deterministic system in some sort of metaphysical sense even though by definition metaphysics cannot be proven.

For me the nonlocal nature of quanta is no more or less puzzling than their wave-like and particle-like nature or their random and orderly nature. For all I know the very concepts themselves are relative like up and down and have no meaning whatsoever outside of specific contexts. Likewise, they may describe something entirely different just as up and down describe a dimension rather than up or down being an absolute. As usual what I suspect is that the depth of this particular puzzle is such that we are missing a very subtle relationship rather than some easy answer such as everything is orderly or random or wave-like or whatever.

 

[arkajad]

As usual what I suspect is that the depth of this particular puzzle is such that we are missing a very subtle relationship rather than some easy answer such as everything is orderly or random or wave-like or whatever.

Perhaps. But perhaps the answer is hidden in plain sight.

 

[wuliheron]

Perhaps. But perhaps the answer is hidden in plain sight.

That seems unlikely after a century of looking, trillions of dollars spent looking, and some 90% of all the scientists who have ever lived being alive today. It also would seem to buck the general trend that the more progress we make the more complex the answers become. Before he died John Wheeler stated that he now believed if we ever found a ToE it would be a simple equation with no metaphysical explanation for why it worked. It seems the more questions we answer, the deeper the remaining mysteries become.

 

[ThomasT]

For me the nonlocal nature of quanta is no more or less puzzling than their wave-like and particle-like nature or their random and orderly nature.

How do you know that the 'nature' of quanta is nonlocal?

As usual what I suspect is that the depth of this particular puzzle is such that we are missing a very subtle relationship rather than some easy answer such as everything is orderly or random or wave-like or whatever.

And I suspect that the deep answer is that everything is orderly, and wavelike. I guess we're all entitled to our own opinions about questions that we'll never answer.

 

[ThomasT]

Perhaps. But perhaps the answer is hidden in plain sight.

I think there's much truth in this. If nature is fundamentally wavelike, and if there's a fundamental wave dynamic, then wouldn't it be evident on any and all scales of behavior? My explanation for the arrow of time is to simply drop a pebble into a calm pool of water and point out the expanding wavefront. Any disturbance in any medium at any scale behaves in this way.

I think that electricity, magnetism and gravity can be explained in terms of this fundamental wave dynamic. And I have no idea how to do that.

 

[nismaratwork]

That seems unlikely after a century of looking, trillions of dollars spent looking, and some 90% of all the scientists who have ever lived being alive today. It also would seem to buck the general trend that the more progress we make the more complex the answers become. Before he died John Wheeler stated that he now believed if we ever found a ToE it would be a simple equation with no metaphysical explanation for why it worked. It seems the more questions we answer, the deeper the remaining mysteries become.

So the answer is '42', but we'll never know the question that tells us why eh?

 

[arkajad]

"Before he died John Wheeler stated that he now believed if we ever found a ToE it would be a simple equation with no metaphysical explanation for why it worked."

The last paragraph in his "Geons, black holes & quantum foam" is a little poem:

"I'd like to know
what this whole show
is all about
before it's out."

I think he is watching us and waiting. So, we better hurry up.

 

[wuliheron]

Wanting to know and expecting to get an answer are two different things. Also, if he is watching I doubt we need hurry. In fact, he may already know the answer, lucky dog. That is, assuming there is an answer and the question isn't meaningless to begin with.

 

[latter]

In uncertain.p at the heart is the claim that there is no cause.because if there was a cause people wouldn't say its not just the tecHnology or equipment.what they actaully mean is there is no cause to it.Because if there was a cause then it wouldn't simply be technology eqiupment,or our acceptance that there is a cause but we as humans can never know it.
you have to get into your head that there is a implicit claim.of no cause at the heart of the uncertain.p.and not just use the phrase uncertain.p to cover this fact up.

Now if the no cause claim was true then you would have a form of pure randomness.
the fACT that what happens is a pacticle doing something slightly to what we would expect makes me suspicious.
if it was pure randomness born from a "no cause" anything could happen at that moment the universe could blow up a horse could appear now in front of your nose white light could appear everywhere .not just particles doing something slighly different even though it seems radical its nothing compared to what could happen because anything can happen with no cause and this is what you have to grasp "anything can happen".not just something slightly different.
of course this form of randomness can never be proved because to prove it you would need a cause.and if you had that cause it wouldn't be this form of randomness.
so here you go a form of pure randomness.
the random where people choose things i can't remmeber my thoughts on this form of randomness..

 

[arkajad]

That is, assuming there is an answer and the question isn't meaningless to begin with.

Well, that's up to us to find it out. Human beings are quite good at giving meaning to things that would be meaningless without them. I mean it is ok to exploit the existing qm as much as we can and even further, but those other dimensions are lurking out there and the old idea of merging, somehow, quantum theory with some kind of geometry has not been exploited enough - I think. Klein's idea didn't work the way we would like, but there is so much of beauty in "geometric quantization" that it would be a surprise if it was purely accidental. Now, what geometry has to do with randomness is an interesting question; but here we have all the research on chaos from hyperbolic dynamics. And meaningful chaos can be practically indistinguishable from meaningless randomness.

 

[inflector]

A nonlocal model is possible, and extant (dBB). But it isn't a mechanistic model. It's as nonrealistic as standard qm is.

How are you defining realistic? dBB is a nonlocal realistic interpretation of QM. According to dBB particles really exist and the wave function is a real wave not just a mathematical device. The very distinguishing characteristic of dBB is the fact that it is a NONLOCAL and REALISTIC theory.

dBB does not make any predictions, but I know some predictions based on dBB and on other models.

dBB has less predictive power than standard qm.

Which should not be a surprise taking into account how much has been invested in the standard qm and how little in the alternatives.

dBB uses exactly the same equations as standard QM. Most consider it to be only an interpretation of QM and as such it is experimentally as verified as QM and is indistinguishable from the other interpretations in this respect.

 

[wuliheron]

Your argument reminds me of Plato who used his influence in Rome to have all of Democritus' books burned as, "ugly and demeaning". He too was enthralled by beauty and order, but it engendered an irrational ugliness and hate within him. Perhaps any answer we do find will be so obscure as to allow each to interpret it however they desire or merely choose to accept it humbly as a gift and use it for the good of all.

 

[inflector]

Your argument reminds me of Plato...

I assume you were replying to arkajad?

 

[arkajad]

Most consider it to be only an interpretation of QM and as such it is experimentally as verified as QM and is indistinguishable from the other interpretations in this respect.

Why should one care about what "most consider it" to be. One should care what it is and not what it is "considered to be". And to know what it is one needs to study it and to use it. Tunneling times predictions are different from those of the standard qm for the simple reason that in standard nonrelativistic qm time is not an "observable" like position or momentum or energy. Therefore all questions about time of arrival must be dealt in qm by some kind of rather arbitrary tricks. This is not so in some of the alternative theories, including dBB.

 

[inflector]

Why should one care about what "most consider it" to be.

It's called a theory or an interpretation by different groups. I haven't seen anything that tells me it is anything other than an interpretation. But I'm open to being educated.

And to know what it is one needs to study it and to use it. Tunneling times predictions are different from those of the standard qm for the simple reason that in standard nonrelativistic qm time is not an "observable" like position or momentum or energy. Therefore all questions about time of arrival must be dealt in qm by some kind of rather arbitrary tricks. This is not so in some of the alternative theories, including dBB.

What are the specific reasons that the arbitrary tricks of which you speak cannot be applied with dBB?

I haven't seen any data or papers that suggest that dBB provides different predictions. Since you must know something I don't here, can you point out any specific papers?

 

[wuliheron]

I assume you were replying to arkajad?

Yes, sorry if that wasn't clear. I'll try to quote people more often.

 

[nismaratwork]

Why should one care about what "most consider it" to be. One should care what it is and not what it is "considered to be". And to know what it is one needs to study it and to use it. Tunneling times predictions are different from those of the standard qm for the simple reason that in standard nonrelativistic qm time is not an "observable" like position or momentum or energy. Therefore all questions about time of arrival must be dealt in qm by some kind of rather arbitrary tricks. This is not so in some of the alternative theories, including dBB.

Because with few exceptional minds aside, when you're swimming upstream in a well established field you're going the wrong way. QM doesn't present the pat answers that dBB does, but what it DOES do is be infallibly predictive so far... dBB can only MATCH QM.

I also note that you said alternative theories, plural... what other theory exists which matches the predictions of QM other than... QM... and dBB?

 

[arkajad]

I also note that you said alternative theories, plural... what other theory exists which matches the predictions of QM other than... QM... and dBB?

Theories with a a dynamical state reduction. There are several such.

"(QM) but what it DOES do is be infallibly predictive"

And when it fails it is said that it is beyond its domain of applicability or that we have a wrong model. Clever.

 

[nismaratwork]

Theories with a a dynamical state reduction. There are several such.

I'm genuinely unfamiliar with them! I thought that QM and dBB were the only two in the building so to speak, do you have any links to these others that I can read about? I would appreciate it, and if they're the type to violate PF guidelines just PM me... I'm curious, not trying to sucker you.

 

[Pythagorean]

I'm genuinely unfamiliar with them! I thought that QM and dBB were the only two in the building so to speak, do you have any links to these others that I can read about? I would appreciate it, and if they're the type to violate PF guidelines just PM me... I'm curious, not trying to sucker you.

It's an easy google; it pertains to the EPR paradox.

 

[nismaratwork]

It's an easy google; it pertains to the EPR paradox.

Done... so something like this? http://arxiv.org/abs/0907.2327

 

[arkajad]

@nismaratwork
And references there.

 

[nismaratwork]

@nismaratwork
And references there.

OK, gotcha, thanks arkajad, Pythagorean, I obviously have a lot of reading to do.

 

[kfmfe04]

Pulling balls from a bag (with replacement) produces a stationary random distribution; ie the higher moments of the distribution is bounded/fixed and is not a function of time.

Is this also true of qm randomness? Aren't there different degrees of mathematical randomness?
I suspect that qm randomness is "messier" but I don't understand it enough to assess.