Examining the Myth of Decoherence & the Measurement Problem

[vanesch]

A word of advice, be very cautious with Zeilinger. He has a tendency to carelessly throw around this word "information" without defining it. Indeed, the first question you should ask about his quote is "information about what?". Moreover, "how does he define information as something on its own?". "Information" always is about something else, in other contexts. For example, the information in history books is about historical events. So what exactly could Zeilinger possibly mean there?

That's also my opinion. In as much as his group does brilliant experiments, I always find the section on the "interpretation" in their papers confusing (confused) as hell.

 

[Coldcall]

Maaneli,

"No but that's the thing, it isn't pure common sense stuff at all. It's very easy to make up interpretations about a physical theory if you don't have knowledge of the mathematics of the theory to constrain your range of interpretive ability. I assure you that a knowledge of the basic mathematics of QM is indispensable to being able to accurately and rigorously interpret QM."

Well I think that's a bit of a cheap shot And exactly the reason why I stick to philosophy forums and keep this away from the physics/maths because we are talking about interpretations. I've read at least 25 different books on Quantum Mechanics and while I don't pretend to understand all the maths I certainly feel I have a reasonably good understanding of quantum theory. Or as well as i could from a non technical layman's perspective.

"Where are you getting this from? Classical physics (in the form of special relativity) is not background independent. Background independence is a property of general relativity, not special relativity. And in neither case is there retrocausality. So I don't know what you're saying."

Yes that's right, GR is BI and SR is BD. What I am arguing is that Quantum mechanics, or whatever fundamental laws our version of QM is describing is background independent. Here's the wiki entry on background independence:

"Background independence is a condition in theoretical physics, especially in quantum gravity (QG), that requires the defining equations of a theory to be independent of the actual shape of the spacetime and the value of various fields within the spacetime, and in particular to not refer to a specific coordinate system or metric. " -my emphasis added.

So what I am saying is your claim that a wave function evolves through time (from the quantum perspective) is not supportable in a background independent theory. The "time" evolution is a space/time mechanism we have bolted on for the benefit of our understanding quantum mechanics in as classical way as possible.

Okay howabout we get an experts opinion? I have a reasonable email relationship with various mathematicians/cosmologists like J.D. Barrow. I'll send him an email about whether we can assume "time" as we understand it is a property of the fundamental quantum world. Okay?

"No this isn't retrocausality. Please take the time to learn the mathematics of QM. I can't debate any further with you on this until you do. Because then it is just your belief in your own interpretation (which is not based on any of the mathematics of QM) versus mine which is solidly based on mathematics of QM"

Okay let's change the word then because you seem to have a hard time accepting retro-causality unless it amounts to particles or waves being sent backwards through time. Howabout "retro-active"? Does that make it easier for you to swallow

"That's a bizarre way of thinking! If you think it is really pushing the credibility envelope to claim there is a determined value before its measured/observed, then I guess you would say classical mechanics and classical electrodynamics are dubious theories in their domain of empirical validity because the equations of motions of particles are deterministic?"

Now I understand why you are willing to speculate wildly as Bohmian Mechanics does that there actually is a definite vlaue to the particle before its measured. Its all about clinging onto a Determinstic worldview! I'd say that is a bizarre way of thinking. What you appear to wnat to do is develop a theory which is compatible with the old classical view of nature. Why are you mixing classical Determinism with quantum mechanics? You may want a Deterministic universe because it matches your philosophical perspective but all the evidence so far suggests that view is not supportable in QM. There are atleast 2 or 3 levels of inherent indeterminism in quantum mechanics. And it seems the only way Bohmiam mechanics deals with the uncertaintly is to claim there is none, and the certainty is just hidden from us by nature's veil.

Suggesting as you have done that quantum mechanics is a classical determinist theory (by making comparisons to Newtonian motion) flies in the face of all evidence. I don't need any maths to clock that. Your and Bohmian proponents that we must keep Determinsim at all costs is almost theological in its fervour.

"An epistemological interpretation of wavefunction superposition is not in contradiction with the idea that there is a particle with a definite position. This is also true of the Hamiltonian in classical mechanics."

Its not in contradiction because we don't know what going on in the superposition. Thats like saying that claiming aliens exist in the universe is not in contradiction to the laws of nature. Yes we know its true of classical mechanics but quantum is not classical!

"I have always been talking about nonrelativistic and relativistic QM, both of which are background-dependent theories. And I thought you were talking about them as well, not quantum gravity. In any case, there are extensions of deBB to quantum gravity and string field theory. But I am not an expert on them."

Any quantum theory is going to have to fit into the bigger picture which will have to include gravity. Hence any genuine quantum intepretation will also have to meet those same requirements for an integrated theory. I'm no expert on either ST or any other quantum gravity theories but I know one thing for sure, and that is they will have to be background independent. Meaning time-independent, and as i mentioned Shrodinger equations can now be forumated to be time-independent because of this very issue about background-independence.

"No you're confusing QM with quantum gravity. They are quite different theories. It is very basic QM that wavefunctions generally have time dependence. When wavefunctions have no time dependence, this is called the stationary state. I recommend learning the theory of QM before getting lost in speculations like these, as it has seriously led you astray."

No I am not confusing anything. I'm making the point that any final theory and Quantum mechanics is far from complete, as is our understanding of gravity. For heavens sakes you don't know whether time exists in a wave function! That is not speculation!

Yes i am speculating that because of the FTL effects of entanglement being instantaneous, even across 10 billion light years, i think there is no "time" as we understand it within the real quantum fundamentals. Can you not understand that the reality we experience with time is forever tied to Relativity no qauntum mechanics?

Yes i realize that Bohmian mechanics attempts to normalise quantum mechanics into some classical facade for the sake of our simple minds. Thanks but i don't need a synthetic reading of quantum mecahnics just because it suits a classical determinist view.

Its funny you go on about maths but you are more wed to your philosophical inclinations than i.

 

[Coldcall]

Maaneli,

About your claim that we know quantum experiences time. I looked this up in my nw version of John Barrow's "New Theories of everything".

Under the chapter title: "The Quantum mystery of Time"

He starts the first paragrapgh by saying:

"In quantum theory the status of time is an even greater mystery than it appeared to Einstein and Newton. IF it exists in a transcedent way then it is not one of those quantities subject to the famous Uncertainty Principle of Heisenberg..."

Okay? Just plain english and common sense. And from a great mathematician too
I guess he should go back to school and learn more maths because he doesn't agree with your point about classical time being applied to quantum fundamentals?

 

[Fra]

deterministic indeterminism

I didn't follow all this thread and maybe this point is uncalled for but.
Coldcall seems to argue in a conceptual manner in a non-mathematical way -

It is basic QM that wavefunctions have a deterministic and unitary evolution. That's true of the Schroedinger evolution in any interpretation.

Suggesting as you have done that quantum mechanics is a classical determinist theory (by making comparisons to Newtonian motion) flies in the face of all evidence. I don't need any maths to clock that.

- I'm not sure if Coldcall referred to the above of Maaneli,

if so, stadnard QM is clearly both indeterministic and deterministic at different layers. The outcome of particular measuresments can't be predicted with certainty (indeterminism), however the probability of any possible outcome is predictable with certainty (determinism), where any uncertainty of the probability goes back to the initial conditions, like in classical mechanics.

Unless it was already clear, this is what the "deterministic evolution of the wavefunction means". "Unitarity" impiles conservation of probability, ie. that the set of all possibilities at all times add upp to 1.

This is what standard QM suggest. In this sense, QM is very simple. I replaces the deductive causality of Newton, with a kind of inductive reasoning that is still deducive to spirit. It considers deductions at probability level, thereby restoring determinism.

But then you can go on and question this. And one may also question where this is entirely consistent when you try to add gravity. One can question the meaning of probability and the sense in having knowledge rather than opinion of a determinate state of the probability?

/Fredrik

 

[Coldcall]

Fra,

"I didn't follow all this thread and maybe this point is uncalled for but.
Coldcall seems to argue in a conceptual manner in a non-mathematical way"

First of all not being a mathematician it would be foolish for me to try to pretend However i check my ideas with mathematicians and I've never ever had anyone say to me "you can't understand this because you don't have the maths".

However even taking maths into account, each and every qm interpretation is mathematically compatible with standard qm maths. Otherwise they would not be valid intepretations and one would have been picked as the "genuine" intepretation. The fact that we have so many standing intepretations means this is not about the maths, but about foundational issues.

"if so, stadnard QM is clearly both indeterministic and deterministic at different layers. The outcome of particular measuresments can't be predicted with certainty (indeterminism), however the probability of any possible outcome is predictable with certainty (determinism), where any uncertainty of the probability goes back to the initial conditions, like in classical mechanics."

Yes I agree there is Determinism and indetermisnim at different levels of physics. But even if only one small variable in a final TOE is non-deterministic it makes the whole system non-dterministic, because once there is any uncertainty, no matter how small an initial condition, it will taint the whole system. The butterfly effect is a prime example of how one small uncertainty works its way up through a system and makes it inherently unpredictable.

And this is the nitty-gritty of interpretations such as Bohm's and others to a lesser extent. They offer no proof of a local or non-local hidden variable. In fact one of their original proponents, John Bell, falsified the local hidden variable theory in the effort of trying to prove it. So while Bell may have been a genius he was wrong about a local theory. So then Bohmians changed it to insist on a so far unexplained non-local variables theory. How convenient! I have an inate distrust of goal-post moving theories such as Bohmian mechanics. In the same way I don't trust String theory, even though its supposed to be beautiful from a mathematical point of view.

So what i am left with to think about Maaneli's ferocious defence of Bohmian mechanics which extends to stooping to a level where he claims I cannot understand because I am not a mathematician? What he is in fact defending is his unshakeable belief that our universe is 100% Determinstic.

My preference is to accept quantum mechanics with its apparent uncertainty until someone proves otherwsie, and Bohmian mechanics proves nothing other than we must have some sort of faith for the sake of an almost theological belief about Determisnim.

New reasearch sheds some light on the repellent influence a Determinstic worldview would have on humanity, which i propose anyone interested in the Determinsim vs Indeterminsim argument reads:

"Destined To Cheat? New Research Finds Free Will Can Keep Us Honest"

http://www.sciencedaily.com/releases/2008/01/080129125354.htm

So while this does not prove a non-deterministic fundamental to the universe; it surely suggests the idea of a Deterministic universe is counter-productive to human progress/evolution.

This is one of the arguments I have always made against the Determinist cause. Arguing for such a universe means that at some stage we can map out the human life on a second by second basis, prediciting how we will live, marry and die - to the utmost accuracy. In my opinion it is a preposterous suggestion. Also Determinism is one step away from predestination. And we know what that entails...

But let's pretend its all as Maaneli and other Bohmians suggest. I suppose they would say this is why the Deterministic nature of Bohmian qm is veiled from nosey humans poking around in the guts of the universe.

Right Maaneli?

 

[Fra]

Coldcall, I've participated in some interpretational threads and I will pass digging deeper in here. That's not to say there aren't many interesting questions.

I am no bomhian to start so I'll pass that this time.

Bell wrote on "professional theoretical physicists ought to be able to do better". I think so too, however I disagree Bohm has the best answer.

Deymystifier is I think the one who can be thought of as the local Bohm-guru on here.

However even taking maths into account, each and every qm interpretation is mathematically compatible with standard qm maths. Otherwise they would not be valid intepretations and one would have been picked as the "genuine" intepretation. The fact that we have so many standing intepretations means this is not about the maths, but about foundational issues.

I think one should distinguish between predictions of mathematics, and the mathematics itself.

I would not say that the mathematical formalism of quantum mechanics is with certainty, uniqely determined from experiment. This is because IMO science does not progress work by deductions. It's not like some one discovered the axioms of quantum mechanics in nature. It is a "theory". But the language of the theory is that of mathematics, but that's not to say that an mathematician would solve the problems of foundatinal physics, no less than it's enough to learn a language to write best selling books. so in this respect I agree with you that mathematics per see is not the problem.

But I figure man developed mathematics for good reason. It was needed for efficient solutions of certain problems.

It could be that there exists, as many times before, a more fundamental formalism - better described by a completely different mathematical formalisms - that still yields the same predictions as QM in the correspondingly special/limiting case. So different mathematics can be consistent with other mathematics to in special cases, within experimental error.

My personal "interpretation" is almost perpendicular to the Bohmian view. I don't look to restore determinism at all levels, I rather suggest that from the scientified perspective, there is an uncertainty in the determinsm at probability level in QM. And my personal ideas will certainly change the mathematic of QM. But I think there is a good logic as to why the standard mathematics of QM is so good. So the new logic will by no means need to contradict the current one.

It is possible argue about these things without much math, but I have no choice but to agree that if you somehow ever aspire on developing your thinking into a full scale theory that can eventually persuade othre people then, what we need is a way to produce numbers that can be tested against numbers produced from measurement devices, which normally leads to mathematical theories.

I think that even for a intrinsic philosoher, some of the basic matehmatics of QM and probability theory is beneficial. You don't need a phd in math or anything. Mainly linear algebra and some calculus.

In particular basic probability theory (bayesian), is even the basis for some philosophical schools of reasoning, from evidence.

/Fredrik

 

[Coldcall]

Fra,

"I am no bomhian to start so I'll pass that this time. Bell wrote on "professional theoretical physicists ought to be able to do better". I think so too, however I disagree Bohm has the best answer. Deymystifier is I think the one who can be thought of as the local Bohm-guru on here."

I agree with your sentiment of Bell's. He was an interesting thinker and tackled the big questions which is more than can be said for many of modern day theorists who shy away from foundational issues. I've not yet had the pleasure of meeting Deymystifier!

"But I figure man developed mathematics for good reason. It was needed for efficient solutions of certain problems."

Maths is vital for humans to conduct physics, make predictions, calculate complex problems etc..Absolutely! What I was trying to say to Maaneli was that our maths for qm is subject to our classical reality. Its a mistake to think that quantum mechanics, behind the veil of non-measurement, is evolving as we imagine it would in a classical environment with "time".

"It is possible argue about these things without much math, but I have no choice but to agree that if you somehow ever aspire on developing your thinking into a full scale theory that can eventually persuade othre people then, what we need is a way to produce numbers that can be tested against numbers produced from measurement devices, which normally leads to mathematical theories. I think that even for a intrinsic philosoher, some of the basic matehmatics of QM and probability theory is beneficial. You don't need a phd in math or anything. Mainly linear algebra and some calculus.

In particular basic probability theory (bayesian), is even the basis for some philosophical schools of reasoning, from evidence."

Yes i agree if i wanted to formulate a whole new interpetation or develop experiments then maths would be essential. But look I'm not a scientist, I left school at 17 and started my business immediately. But hey i know how to read a set of accounting books Of course I have a strong interest from a foundational point of view, and if I had the time to take a crash course in calculus i certainly would, as i admire the way mathematics can neatly deal wth "some" complex problems.

But there is a real danger when i see people hide behind maths as an excuse not to explain themselves in a logical consistent manner. We got to this situation because i simply did not agree with Maaneli's favoured interpretation so he says it must be because I'm not a mathematician.

If someone doesn't agree with my (interpretation) i certainly would not say its because its above their level of understanding.

 

[Fra]

But there is a real danger when i see people hide behind maths as an excuse not to explain themselves in a logical consistent manner. We got to this situation because i simply did not agree with Maaneli's favoured interpretation so he says it must be because I'm not a mathematician.

If someone doesn't agree with my (interpretation) i certainly would not say its because its above their level of understanding.

In a way communication, is certainly a mutual thing. So if I don't understand you, or you doesn't understand me, it's a mutual problem to solve if we want to understand each other. Sometimes one party may hold the opinion that their language is standard.

Of course it could be plain difficult to explain what is usually described in mathematics, in plain english. To do that I think takes even more skill because not only do you need to understand something in one language, you have to see beyond tha language and try to convey it in a different way. Some authors of books, have it seems to have talent for that, while some are consistently very dry and focus only of the mathematics, but then they apparently have no intetion to communicate to anyone but other similar minds.

I feel that sometimes, ideas or concepts, are more easily expressed in english but the same as with languages and math, it only works if the receptor is somewhat on the same page so to speak.

/Fredrik

 

[Coldcall]

Hi Fra,

"Of course it could be plain difficult to explain what is usually described in mathematics, in plain english. To do that I think takes even more skill because not only do you need to understand something in one language, you have to see beyond tha language and try to convey it in a different way. Some authors of books, have it seems to have talent for that, while some are consistently very dry and focus only of the mathematics, but then they apparently have no intetion to communicate to anyone but other similar minds."

Yes if there is a substantative foundational difference because of a mathematical truth, not just a re-formulation or framework, then i agree that to understand the maths would be a very helpful thing. And to use these new physical insights maths is unavoidable.

But what's interesting is that looking at the motion of planets which is a very simple conceptual idea, can also be explained in mathematics. Now if someone just looked at the maths without having been trained (or knowing that this related to the motion of planets) they would not understand what it could be telling them. However it could be reasonably well explained with a stick scraping out the idea on a sandy beach.

So you see this is why i maintain that anything that can have any real significance on our fundamental understanding about the universe, should not be difficult to explain. It may take some innovative analogies, but we are intelligent enough, and have enough imagination to understand these important concepts - without constructing barriers subject to being a mathematician.

 

[Maaneli]

Well I think that's a bit of a cheap shot And exactly the reason why I stick to philosophy forums and keep this away from the physics/maths because we are talking about interpretations. I've read at least 25 different books on Quantum Mechanics and while I don't pretend to understand all the maths I certainly feel I have a reasonably good understanding of quantum theory. Or as well as i could from a non technical layman's perspective.


It may be a cheap shot but it's the harsh truth. Keeping to philosophy forums doesn't justify this any better. All the serious philosophers of QM know the very basic mathematics of QM (and you don't have to be a mathematician to do this) which is why they have any semblance of credibility and coherence to their ideas. It's not about what you feel you understand. Can you write down the Schroedinger equation and general wavefunction solution? And can you identify what the Hilbert space and configuration space of QM are? Look, I could tediously take the time to explain all this to you in english and some math (which I already have tried actually), but I don't have the time or patience to do that any further, because you don't seem to know some very basic prerequisites.





Yes that's right, GR is BI and SR is BD. What I am arguing is that Quantum mechanics, or whatever fundamental laws our version of QM is describing is background independent. Here's the wiki entry on background independence:

"Background independence is a condition in theoretical physics, especially in quantum gravity (QG), that requires the defining equations of a theory to be independent of the actual shape of the spacetime and the value of various fields within the spacetime, and in particular to not refer to a specific coordinate system or metric. " -my emphasis added.

So what I am saying is your claim that a wave function evolves through time (from the quantum perspective) is not supportable in a background independent theory. The "time" evolution is a space/time mechanism we have bolted on for the benefit of our understanding quantum mechanics in as classical way as possible.


Yes in a BD theory time is not fundamental. That would however be problematic for ANY interpretation of QM based on wavefunctions. Look, the nonrelativistic Schroedinger equation and the relativistic Dirac equation both have time-dependent wavefunctions. That's very standard and well known. You're asking a question about quantum gravity which is a different issue. In terms of deBB, there is nonetheless an extension of it to a BD quantum gravity theory, namely, string field theory.


Okay howabout we get an experts opinion? I have a reasonable email relationship with various mathematicians/cosmologists like J.D. Barrow. I'll send him an email about whether we can assume "time" as we understand it is a property of the fundamental quantum world. Okay?


We don't really need his opinion on this, as this is not a controversial issue at all. But, if you want to as him anything, ask him exactly this: do wavefunctions have time-dependence in standard nonrelativistic and relativistic quantum mechanics? And what is meant by a stationary state in QM?

And make sure to tell him this is not a question about quantum gravity.



Okay let's change the word then because you seem to have a hard time accepting retro-causality unless it amounts to particles or waves being sent backwards through time. Howabout "retro-active"? Does that make it easier for you to swallow


Retrocausality has a very definite meaning in the foundations of physics literature. You just seem to be ignoring that and redefining things as you feel like it. That's the problem I have with you using the word "retrocausality" to describe QM nonlocality.



Now I understand why you are willing to speculate wildly as Bohmian Mechanics does that there actually is a definite vlaue to the particle before its measured. Its all about clinging onto a Determinstic worldview! I'd say that is a bizarre way of thinking. What you appear to wnat to do is develop a theory which is compatible with the old classical view of nature. Why are you mixing classical Determinism with quantum mechanics? You may want a Deterministic universe because it matches your philosophical perspective but all the evidence so far suggests that view is not supportable in QM. There are atleast 2 or 3 levels of inherent indeterminism in quantum mechanics. And it seems the only way Bohmiam mechanics deals with the uncertaintly is to claim there is none, and the certainty is just hidden from us by nature's veil.


Once again there is nothing wildly speculative about formulating QM into a fully realist theory of physical processes. It is perfectly consistent with everything we see, unlike the solipsistic interpretations. Moreover, determinism isn't the main point of deBB or of realist formulations of QM. There are stochastic versions of deBB that are also realist theories. Also, determinisim is not something intrinsic to just classical physics. That's an example of an error you're making by not understanding the basics of QM. The Schroedinger wavefunction evolves deterministically via the Schroedinger equation. The measurement postulates are what introduce indeterminism. Of course, the measurement postulates are hopelessly vague, ad-hoc, and anthropic, and this is the cause of the measurement problem as well as the inability of standard QM to describe the quantum-classical limit. The basic deBB theory just replaces those ad-hoc measurement postulates with a mathematically precise equation of motion for a particle that depends on the deterministic wavefunction evolution, and from this is able to derive ALL the quantum statistics without further postulates or fundamental reference to human beings.


Suggesting as you have done that quantum mechanics is a classical determinist theory (by making comparisons to Newtonian motion) flies in the face of all evidence. I don't need any maths to clock that. Your and Bohmian proponents that we must keep Determinsim at all costs is almost theological in its fervour.

You missed the point entirely before. As I already explained, the determinisim has nothing to do with classical physics, but rather the determinism of wavefunction time evolution. Moreover, as I have already exlained, there are stochastic deBB theories and there is no fervor in keeping determinism. The point is that we should only be introducing stochastiticty in a theory in a mathematically and physically precise way. By the way, that is why many Bohmians like Bell are also proponents of stochastic wavefunction collapse theories like GRW.



Its not in contradiction because we don't know what going on in the superposition. Thats like saying that claiming aliens exist in the universe is not in contradiction to the laws of nature. Yes we know its true of classical mechanics but quantum is not classical!

Missed the point again. It has nothing to do with details of superposition, quantum or classical. The point is just that there is nothing mathematically inconsistent about writing down an equation of motion for a particle in terms of something mathematically abstract (like the quantum wavefunction or classical Hamiltonian). Yes of course there are differences in details that still should be explored, but that is not my point. And please don't bother to insist that it is.

 

[Maaneli]

Maaneli,

About your claim that we know quantum experiences time. I looked this up in my nw version of John Barrow's "New Theories of everything".

Under the chapter title: "The Quantum mystery of Time"

He starts the first paragrapgh by saying:

"In quantum theory the status of time is an even greater mystery than it appeared to Einstein and Newton. IF it exists in a transcedent way then it is not one of those quantities subject to the famous Uncertainty Principle of Heisenberg..."

Okay? Just plain english and common sense. And from a great mathematician too
I guess he should go back to school and learn more maths because he doesn't agree with your point about classical time being applied to quantum fundamentals?

LOL, I don't think you understood what he means. He's not denying that there is a time parameter in QM and that wavefunctions have a time-dependent evolution. What he is worrying about is the physical interpretation of the time parameter in QM, and rightly so if he is starting from the assumption that the orthodox intepretation of QM and the HUP is fundamentally correct.

 

[Coldcall]

LOL, I don't think you understood what he means. He's not denying that there is a time parameter in QM and that wavefunctions have a time-dependent evolution. What he is worrying about is the physical interpretation of the time parameter in QM, and rightly so if he is starting from the assumption that the orthodox intepretation of QM and the HUP is fundamentally correct.

You are back peddling here big time My original point was about whether "time" existed at the deepest quantum fundamental - which is something Barrow admits is an open question. Same thing I said (perhaps poorly) but you argued against that saying that we could be certain that time exists in the quantum level - even leaving aside our classical coniderations.

Before i posted the Barrow comments you expressed no distinction between our sense of time, and whatever is going on at the fundamental quantum end. And whenever i tried to raise this difference of time perspectives you completely ignored the idea. No wonder i am skeptical of so-called forum maths exerts - especially ones with severe Determinist tendencies

 

[Coldcall]

Maaneli,

"Look, I could tediously take the time to explain all this to you in english and some math (which I already have tried actually), but I don't have the time or patience to do that any further, because you don't seem to know some very basic prerequisites."

Unfortunatley all I've really heard from you are tedious excuses or contradictions. The reason you don't make any sense is because you appear to be brainwashed with a emotional attachement to super-determinsim. Maybe you need to look at that study about what your brand of super-determinsim does to people's minds and then do a little inward refelction.
"Destined To Cheat? New Research Finds Free Will Can Keep Us Honest"
http://www.sciencedaily.com/releases...0129125354.htm

" You're asking a question about quantum gravity which is a different issue."

We are talking about foundational issues here so any genuine quantum gravity theory would necessarily impact upon any genuine intepretation of quantum theory or vice versa.

"In terms of deBB, there is nonetheless an extension of it to a BD quantum gravity theory, namely, string field theory."

There you go. This why you are confusing. Check out the last two statements you've made. Its as if these things have to be dragged out of you kicking and screaming.

"We don't really need his opinion on this, as this is not a controversial issue at all. But, if you want to as him anything, ask him exactly this: do wavefunctions have time-dependence in standard nonrelativistic and relativistic quantum mechanics?"

If my orignal point was not controversial why were you arguing? You know and I know i was making a distinction between our practical application of quantum mechanics from a classical perspective (ie. time), and the question of time at a deeper fundamental level. You refused to accept such distinctions. And i even mentioned the Shrodinger equation before you did just to make sure you understood the distinction, but then again you just barged ahead.

"And what is meant by a stationary state in QM? And make sure to tell him this is not a question about quantum gravity."

Here we go again It is, its not, it is, its not - LOL

"Retrocausality has a very definite meaning in the foundations of physics literature. You just seem to be ignoring that and redefining things as you feel like it. That's the problem I have with you using the word "retrocausality" to describe QM nonlocality."

It is an open argument whether retrocausality is an accurate way to define the effects of Wheeler's Delayed choice or Quantum experiment, or even entanglement. Its ongoing:
http://en.wikipedia.org/wiki/Retrocausality

But I am willing to concede to you sir the use of the word, for retro-active instead, because it doesn't really matter in as far as the instantaneous effects of entanglement across large distances is a known. My point was that our limited glimpse of this "spooky action at a distance" may be indicating that on that fundamental (non-classical) level of quantum mechanics it operates outside of "time". Entanglement seems to be one of the few observable effects we know about whatever is the guts of fundamental quantum mechanics. And the fact that the effect is apparently instantaneous even if tested across lightyears should make us stop and think for a moment what that could be telling us about whatever level of the universe quantum mechanics is reaching into, or out of. We cannot know that our maths (with the classically constucted time-dependence) is describing that fundamental level.

And surely you must agree with that if you are going to stay true to Bohmian principles - namely quantum mechanics is as of yet incomplete? Right? We may not agree on things like the Determinsim inherent in Bohmian mechanics but i would have thought you'd keep an open mind about the status of "time" in any true fundamental theory.

"Also, determinisim is not something intrinsic to just classical physics."

Its not even *intrinsic* to classical mechanics. There were plenty of early classical scientists along the way who warned about the impossibility of knowing all starting conditions at anyone given time. Then there's chaos and the butterfly effect which should be classed as classical non deterministic emergent behaviour. You only cling on to any concepts which promote a Deterministic worldview, because for you to admit just one non-deterministic system exists - breaks your whole philosophical pro-Determinsim bias. Which frankly is why you and most strong Determinists hook up so closely to Bohmian theory.

Am i right or wrong about that?

"The point is just that there is nothing mathematically inconsistent about writing down an equation of motion for a particle in terms of something mathematically abstract (like the quantum wavefunction or classical Hamiltonian). Yes of course there are differences in details that still should be explored, but that is not my point. And please don't bother to insist that it is."

Thank heavens you've at least said "abstract". You know this has been my whole point all along in relation to the wonderful feats you attributed to Bohmian mechanics. They most certainyly are abstracts and by saying so you admit - rather belatedly - that the maths we use for these quantum calculations are indeed abstract for the simple reason we don't really know either the status of a "reality" or "time" inside the wave function.

In any case. I've never questionaed any of the maths from our classical perspective, but the fact is the maths for all intepretations works as well as the others. Thats a well documented fact even without a maths degree.

The only difference in Bohmian theory that I can establish after all this, is that it represents a neo-classical Determinist view of quantum mechanics. Its deeply motivated by a philosophical or theological angst about the nature of reality. Sad but true.

From Bohm to Bell, to Legett; its sad to see the house of cards coming down boys.
Oh yeah, now I know why you have not much nice to say about the brilliant Anton Zeilinger, he slam-dunked Legett's tests for quantum realism. Ouch.

 

[Hurkyl]

The reason you don't make any sense is because you appear to be brainwashed with a emotional attachement to super-determinsim.

Or maybe... just maybe... the problem is with you?

 

[Coldcall]

Or maybe... just maybe... the problem is with you?

I doubt it and there is an ever increasing amount of evidence which confirms that realism is non-existent at the quantum mechanical level. Get use to it guys. Party is over for Determinism and once Zeilinger finally ejects the primitive idea of realism at the quantum level, you'll have to reformulate Bohmain so it makes some sense to someone. I can hear the clenching of arses

http://seedmagazine.com/news/2008/06/the_reality_tests_1.php?page=all&p=y

http://www.nature.com/nature/journal/v446/n7138/full/nature05677.html

"Most working scientists hold fast to the concept of 'realism'—a viewpoint according to which an external reality exists independent of observation. But quantum physics has shattered some of our cornerstone beliefs. According to Bell's theorem, any theory that is based on the joint assumption of realism and locality (meaning that local events cannot be affected by actions in space-like separated regions) is at variance with certain quantum predictions. Experiments with entangled pairs of particles have amply confirmed these quantum predictions, thus rendering local realistic theories untenable. Maintaining realism as a fundamental concept would therefore necessitate the introduction of 'spooky' actions that defy locality. Here we show by both theory and experiment that a broad and rather reasonable class of such non-local realistic theories is incompatible with experimentally observable quantum correlations. In the experiment, we measure previously untested correlations between two entangled photons, and show that these correlations violate an inequality proposed by Leggett for non-local realistic theories. Our result suggests that giving up the concept of locality is not sufficient to be consistent with quantum experiments, unless certain intuitive features of realism are abandoned."

http://arxiv.org/PS_cache/arxiv/pdf/0801/0801.3050v1.pdf

"The before-before experiment demonstrates free will acting from outside space-time. The experimental violation of the Leggett’s inequality supports the view that it is not appropriate to attempt to limit this freedom in Nature by forcing it to mimic classical features."

http://physicsworld.com/cws/article/print/34774

"A quantum renaissance"

 

[Hurkyl]

I doubt it and there is an ever increasing amount of evidence which confirms that realism is non-existent at the quantum mechanical level.

What sort of evidence? It's certainly not empirical -- all of the major interpretations are observationally indistinguishable. It's certainly not logical; the existence of realist interpretations proves that such an argument cannot exist. (Assuming the consistency of logic and the corresponding mathematics) (also assuming you are not assigning an exotic meaning to the word 'realism') Argumentum ad populum is a

So what sort of evidence could it be? And if it's neither empirical nor logical, why should I listen to it?


Your citation speaks only of a certain class of theories -- assuming their conclusion is correct, that class must exclude both the Bohm interpretation and the many-worlds interpretation.

 

[Coldcall]

What sort of evidence? It's certainly not empirical -- all of the major interpretations are observationally indistinguishable. It's certainly not logical; the existence of realist interpretations proves that such an argument cannot exist. (Assuming the consistency of logic and the corresponding mathematics) (also assuming you are not assigning an exotic meaning to the word 'realism') Argumentum ad populum is a

So what sort of evidence could it be? And if it's neither empirical nor logical, why should I listen to it?

Your citation speaks only of a certain class of theories -- assuming their conclusion is correct, that class must exclude both the Bohm interpretation and the many-worlds interpretation.

On checking the time of my previous post with the links and this response of yours I KNOW you could not have looked at those articles. The one in Seed is very long just on its own. How could i know that without having observed you? Wow , according to your *beliefs* that must mean hidden variables exist!

I suggest you and Maaneli call together some Bohmian conference in order to induce mass panic amongst the evangelical ranks of super-Determinists.

Anyways i certainly can't un-brainwash you lot- so i will go and have a nice Saturday afternoon, Cheerio!

 

[Hurkyl]

On checking the time of my previous post with the links and this response of yours I KNOW you could not have looked at those articles.

You're right, I didn't read them in their entirety; I simply skimmed them long enough to realize they are a red herring. And then I realized I didn't even have to bother with that, because the parts you quoted said they were a red herring.

 

[Maaneli]

You are back peddling here big time My original point was about whether "time" existed at the deepest quantum fundamental - which is something Barrow admits is an open question. Same thing I said (perhaps poorly) but you argued against that saying that we could be certain that time exists in the quantum level - even leaving aside our classical coniderations.

Before i posted the Barrow comments you expressed no distinction between our sense of time, and whatever is going on at the fundamental quantum end. And whenever i tried to raise this difference of time perspectives you completely ignored the idea. No wonder i am skeptical of so-called forum maths exerts - especially ones with severe Determinist tendencies

<< Before i posted the Barrow comments you expressed no distinction between our sense of time, and whatever is going on at the fundamental quantum end. >>

I was not talking about our sense of time, I was talking about the existence of the time parameter in wavefunctions obeying the time-dependent Schroedinger equation.

<< You are back peddling here big time My original point was about whether "time" existed at the deepest quantum fundamental - which is something Barrow admits is an open question. >>

This isn't back peddaling. This is correcting your misunderstanding of what Barrow is worrying about. Furthermore, I thought we were always talking about nonrelativistic and relativistic QM, not quantum gravity until a couple posts ago. This word "deepest level" is ridiculously vague, and if you want people to know what you're talking about, you got to be precise about what you're talking about. Finally, you were claiming that time "does not exist" in QM, which is something that Barrow clearly doesn't claim, and which you certainly have no evidence for, and so to claim this as if it is obvious or well accepted, is simply disingenuous. But then again, that's not surprising considering how conveniently disingenuous you have been in your last couple posts by trying to brand me as a hard-core determinist, even though I repeatedly pointed out that I am not so and that determinism is not the main point or purpose of deBB theory, and that there are stochastic versions of deBB, and that GRW theory is a purely stochastic theory. Maybe you just don't know what the word "stochastic" means, in which case you should say so before making any more assumptions. By the way, I think it's fair to say that you're quickly losing credibility in this forum based on my impressions, and your interactions with the others.

 

[Maaneli]

I doubt it and there is an ever increasing amount of evidence which confirms that realism is non-existent at the quantum mechanical level. Get use to it guys. Party is over for Determinism and once Zeilinger finally ejects the primitive idea of realism at the quantum level, you'll have to reformulate Bohmain so it makes some sense to someone. I can hear the clenching of arses

http://seedmagazine.com/news/2008/06/the_reality_tests_1.php?page=all&p=y

http://www.nature.com/nature/journal/v446/n7138/full/nature05677.html

"Most working scientists hold fast to the concept of 'realism'—a viewpoint according to which an external reality exists independent of observation. But quantum physics has shattered some of our cornerstone beliefs. According to Bell's theorem, any theory that is based on the joint assumption of realism and locality (meaning that local events cannot be affected by actions in space-like separated regions) is at variance with certain quantum predictions. Experiments with entangled pairs of particles have amply confirmed these quantum predictions, thus rendering local realistic theories untenable. Maintaining realism as a fundamental concept would therefore necessitate the introduction of 'spooky' actions that defy locality. Here we show by both theory and experiment that a broad and rather reasonable class of such non-local realistic theories is incompatible with experimentally observable quantum correlations. In the experiment, we measure previously untested correlations between two entangled photons, and show that these correlations violate an inequality proposed by Leggett for non-local realistic theories. Our result suggests that giving up the concept of locality is not sufficient to be consistent with quantum experiments, unless certain intuitive features of realism are abandoned."

http://arxiv.org/PS_cache/arxiv/pdf/0801/0801.3050v1.pdf

"The before-before experiment demonstrates free will acting from outside space-time. The experimental violation of the Leggett’s inequality supports the view that it is not appropriate to attempt to limit this freedom in Nature by forcing it to mimic classical features."

http://physicsworld.com/cws/article/print/34774

"A quantum renaissance"

Yes I looked at this too. Indeed it is all BS red herring stuff.

 

[jostpuur]

I doubt it and there is an ever increasing amount of evidence which confirms that realism is non-existent at the quantum mechanical level. Get use to it guys. Party is over for Determinism...

Claims like this implicitly assume that the "realism" must be kind of realism of Bohmian interpretation or something similar. I think that the wave functions of QM are the objective reality (according to the best current knowledge), and I don't see any reason for changing philosophical attitude towards reality.

It would be notably bad terminology to choose such meaning for the word "reality", that the reality would not exist!

 

[Coldcall]

You're right, I didn't read them in their entirety; I simply skimmed them long enough to realize they are a red herring. And then I realized I didn't even have to bother with that, because the parts you quoted said they were a red herring.

LOL, of course you don't have to bother. I would not want anything to burst your little bubble of Determinist insecurity.

What your's and Maaneli's behaviour proves to me beyond a reasonable doubt; is that it would not matter how much proof or evidence appears which contradicts either local or non-local realism. I hope neither of you work in the sciences because you would be about as useful as an ID proponent or Creationist. Very sad indeed.

 

[jostpuur]

What do you mean by "realism"? Is it synonym with "determinism"?

 

[Coldcall]

Maaneli,

" was not talking about our sense of time, I was talking about the existence of the time parameter in wavefunctions obeying the time-dependent Schroedinger equation"

I mentioned the Schrodinger equation first, not you. I did that in order for you to distinguish between how we treat "time" and whether time actually exists in an independent fashion in the quantum realm. Problem is you seem unable to separate our classical reality from the quantum world. You appear to think they are one and the same. You're plain wrong.

"Finally, you were claiming that time "does not exist" in QM, which is something that Barrow clearly doesn't claim, and which you certainly have no evidence for, and so to claim this as if it is obvious or well accepted, is simply disingenuous."

But we don't know whether time exists in the fundamental quantum world. Thats a bloody fact! You seem intellectually unable to understand that "time" is a human measurement construct for our classical reality. Of course since you believe in fairytale hidden variables I guess it should not be surprising that you insist on the quantum world behaving with the same heuristic properties as our classical reality. You're wrong again. And for a guy who is such a maths-head you certainly lack some very basic logic skills.

And yes there is cirucmstantial evidence that within the quantum mechanism responsible for entanglement, time has no meaning. Why? Because its effects are instantaneous. Its just obvious..well obvious to anyone but you and Hurkyl, and i suppose any other self-deluded Bohmians who are holding onto quantum realism for their lives.

Additionally it was noted 30 or 40 years ago that any cosmological quantum theory which treated the universe as a wave function could not include a time function as we understand it. It had to be based on discreet transitions. ie: Wheeler-DeWitt equation. Such a universal wave function mapped from the moment of the big bang is necessarily fundamental since space/time would not yet have been created.

The fact that you keep banging on about "time" as if its something fundamental shows you really don't understand the wider picture. Are you involved in science at a professional level? Please do answer - I am very curious.

"But then again, that's not surprising considering how conveniently disingenuous you have been in your last couple posts by trying to brand me as a hard-core determinist, even though I repeatedly pointed out that I am not so and that determinism is not the main point or purpose of deBB theory"

You are clearly a Determinist by the very fact you support a compeletely fanciful idea that a particle in a wave function has a defintie value before its measured...but its just hidden from us. Bohmian mecahnics is the last refuge of Determinists, and by denying this it is you who is acting dishonestly. Not only that but you reject as red herrings any experiments which remove realism from a quantum state before its measured. That is bonafide Determinism.

"By the way, I think it's fair to say that you're quickly losing credibility in this forum based on my impressions, and your interactions with the others."

LOL, how old are you exactly? You sound like you are ready for summer camp where you can make lots of friends.

 

[Coldcall]

What do you mean by "realism"? Is it synonym with "determinism"?

Its not synonymous but its very tightly connected, particularly in quantum intepretations. If you want to understand what this is about read the (June) Seed article - it covers some new experiments on the way from Anton Zeilinger and tells the history about the argument which started long ago between Einstein and Bohr. Whats funny here is that Determinists like Legett have just about thrown the towel in but as you can see Maaneli and Hurkyl refuse to believe what science is telling them. Go figure

http://seedmagazine.com/news/2008/06...p?page=all&p=y

 

[Hurkyl]

is that it would not matter how much proof or evidence appears which contradicts either local or non-local realism.

When such proof appears, it would give rise to an interesting discussion. (And would be an incredibly important advance, because it would yield a contradiction to quantum mechanics, thus finally giving a lead towards the next theory of the universe) Until then, I suggest you brush up on your reading comprehension and logic. The former so that you realize the papers you cite only refer to a certain class of 'realist' theories, and the latter so realize that "some X can't be true" is not a proof of "all X are false".

 

[Coldcall]

When such proof appears, it would give rise to an interesting discussion. (And would be an incredibly important advance, because it would yield a contradiction to quantum mechanics, thus finally giving a lead towards the next theory of the universe) Until then, I suggest you brush up on your reading comprehension and logic. The former so that you realize the papers you cite only refer to a certain class of 'realist' theories, and the latter so realize that "some X can't be true" is not a proof of "all X are false".

Hurkyl,

First of all, let's not forget Bohmian mechanics is an "interpretation", which joins the ranks of many other "interpretations" which all equally predict the same quantum mechanical outcomes. The difference with Bohmian mechanics is that it alone asks us to take as an article of faith, that something is indeed occurring of which there is absolutely no proof, ie: a defined value for a particle before measurement/observation.

So let's remember that really it should be on Bohmians to prove this rather mystical intepretation. And this has been seriously attempted twice; first Bell, then Legett (with some tests for non-local realism theories).

Legett's specific non-local realism theories have been falsified and no-one questions that fact.

http://arxiv.org/abs/0708.0584

So while this did not specifically falsify Bohmian mechanics, it is a further step in closing down this absurd notions of hidden variables and quantum realism. I could just as easily say that there are invisible elastic bands controlling gravity, and of course it would be ridiculously hard to falsify. So its no wonder that Bohmians motives are questioned when there is zero evidence to support their theory. It completely un-scientific.

 

[Maaneli]

[/B]

Maaneli,

" was not talking about our sense of time, I was talking about the existence of the time parameter in wavefunctions obeying the time-dependent Schroedinger equation"

I mentioned the Schrodinger equation first, not you. I did that in order for you to distinguish between how we treat "time" and whether time actually exists in an independent fashion in the quantum realm. Problem is you seem unable to separate our classical reality from the quantum world. You appear to think they are one and the same. You're plain wrong.

"Finally, you were claiming that time "does not exist" in QM, which is something that Barrow clearly doesn't claim, and which you certainly have no evidence for, and so to claim this as if it is obvious or well accepted, is simply disingenuous."

But we don't know whether time exists in the fundamental quantum world. Thats a bloody fact! You seem intellectually unable to understand that "time" is a human measurement construct for our classical reality. Of course since you believe in fairytale hidden variables I guess it should not be surprising that you insist on the quantum world behaving with the same heuristic properties as our classical reality. You're wrong again. And for a guy who is such a maths-head you certainly lack some very basic logic skills.

And yes there is cirucmstantial evidence that within the quantum mechanism responsible for entanglement, time has no meaning. Why? Because its effects are instantaneous. Its just obvious..well obvious to anyone but you and Hurkyl, and i suppose any other self-deluded Bohmians who are holding onto quantum realism for their lives.

Additionally it was noted 30 or 40 years ago that any cosmological quantum theory which treated the universe as a wave function could not include a time function as we understand it. It had to be based on discreet transitions. ie: Wheeler-DeWitt equation. Such a universal wave function mapped from the moment of the big bang is necessarily fundamental since space/time would not yet have been created.

The fact that you keep banging on about "time" as if its something fundamental shows you really don't understand the wider picture. Are you involved in science at a professional level? Please do answer - I am very curious.

"But then again, that's not surprising considering how conveniently disingenuous you have been in your last couple posts by trying to brand me as a hard-core determinist, even though I repeatedly pointed out that I am not so and that determinism is not the main point or purpose of deBB theory"

You are clearly a Determinist by the very fact you support a compeletely fanciful idea that a particle in a wave function has a defintie value before its measured...but its just hidden from us. Bohmian mecahnics is the last refuge of Determinists, and by denying this it is you who is acting dishonestly. Not only that but you reject as red herrings any experiments which remove realism from a quantum state before its measured. That is bonafide Determinism.

"By the way, I think it's fair to say that you're quickly losing credibility in this forum based on my impressions, and your interactions with the others."

LOL, how old are you exactly? You sound like you are ready for summer camp where you can make lots of friends.

<< I mentioned the Schrodinger equation first, not you. >>


I doubt that. And even if you did, then you really have no excuse for insisting that time does not exist in QM. I agree the time parameter in QM is classical, but that doesn't mean time doesn't exist in QM or that I'm putting classical physics in QM (it is just a basic fact about Schroedinger wave mechanics). That was my point which in your hotheadedness seem to have overlooked.


<< But we don't know whether time exists in the fundamental quantum world. Thats a bloody fact! You seem intellectually unable to understand that "time" is a human measurement construct for our classical reality. >>


First you say you don't believe time exists in QM, now you're saying we don't know if time exist in QM. Which is you believe. Look, we have evidence that something like time exists in QM by the mere fact that there is a t-parameter in the Schroedinger evolution for subsystems.


<< And for a guy who is such a maths-head you certainly lack some very basic logic skills. >>

If by logic you mean YOUR ambiguous and confused style of reasoning, then I admit that.


<< And yes there is cirucmstantial evidence that within the quantum mechanism responsible for entanglement, time has no meaning. Why? Because its effects are instantaneous >>


Tsk, tsk. Let me ask you a question Einstein. If time doesn't exist, then what is the meaning of instantaneous? And I guess by your logic, the fact that there exists instantaneous velocity in CM means that time does not exist in CM either.


<< It had to be based on discreet transitions. ie: Wheeler-DeWitt equation. Such a universal wave function mapped from the moment of the big bang is necessarily fundamental since space/time would not yet have been created. >>

You should also know that the Wheeler-DeWitt equation is controversial in QG research. Meaning that not everyone thinks it is a valid equation to describe QG.


<< Are you involved in science at a professional level? Please do answer - I am very curious. >>


Of course. Are you? No!


<< You are clearly a Determinist by the very fact you support a compeletely fanciful idea that a particle in a wave function has a defintie value before its measured...but its just hidden from us. >>


Now you've proven you don't even understand the basics of standard QM. And thank you for admitting you are disingenuous.

 

[Maaneli]

LOL, of course you don't have to bother. I would not want anything to burst your little bubble of Determinist insecurity.

What your's and Maaneli's behaviour proves to me beyond a reasonable doubt; is that it would not matter how much proof or evidence appears which contradicts either local or non-local realism. I hope neither of you work in the sciences because you would be about as useful as an ID proponent or Creationist. Very sad indeed.

<< I hope neither of you work in the sciences because you would be about as useful as an ID proponent or Creationist. Very sad indeed. >>


I guess this is your way of overcompensating for your own insecurities about not having any academic degree. I pity you a bit.

Well, whatever, in the end nothing you think matters because I am a physicist, you're not, and in fact you don't even have a HS or college degree and never will. So cheerio!

 

[Hurkyl]

Coldcall:
Just to make sure it's crystal clear -- you have retracted your claim that evidence contradicts realism, correct?

Anyways, are you arguing for solipsism? If not, then your current argument carries no force, since any other epistemological position requires an 'article of faith'.

So its no wonder that Bohmians motives are questioned when there is zero evidence to support their theory.

Eh? BM, like all interpretations of QM (that don't make changes), is the best tested theory in the history of mankind.

It completely un-scientific.

Eh? Interpretation is a part of science, both in the practice and the pedagogy, since it is a prerequisite to applying math & logic to the study of reality.