Interesting paper on a fractal model to resolve the Einstein/Bohr dispute

democrates

Article in New Scientist titled "Can fractals make sense of the quantum world?"

Royal Society Paper at arXiv titled "The Invariant Set Hypothesis: A New Geometric Framework for the Foundations of Quantum Theory and the Role Played by Gravity"

Tim Palmer outlines a thought provoking model based on the idea that in a chaotic system the invariant set is a fractal, by applying this to the universe he posits that quantum theory is indeed incomplete, but may be so simply due to the alleged fractal nature of the universe - ie the necessary resolution is not being applied to match the fine fractal detail. He believes that 'spooky' effects may in fact be explained by this model which allows for infinite resolution but is ultimately deterministic.

Personally I like the fractal idea, I've never been comfortable with the notion of an indivisible particle - everything is made of something.

Professor_Fink

democrates wrote: »

Personally I like the fractal idea, I've never been comfortable with the notion of an indivisible particle - everything is made of something.

Turtles all the way down, eh?

I hate to point it out, but the Einstein-Bohr dispute has long been settled. Einstein was simply wrong in thinking that quantum mechanics did not accurately describe the world. In fact, the EPR states used in his thought experiment are no routinely made and measured in labs throughout the world.

In fact you can make them yourself with a pocket laser pointer and an appropriate non-linear crystal.

democrates

Professor_Fink wrote: »

Turtles all the way down, eh?

I hate to point it out, but the Einstein-Bohr dispute has long been settled. Einstein was simply wrong in thinking that quantum mechanics did not accurately describe the world. In fact, the EPR states used in his thought experiment are no routinely made and measured in labs throughout the world.

In fact you can make them yourself with a pocket laser pointer and an appropriate non-linear crystal.

Turtles may be slow, but they're tenacious .

Quantum theory is not a toe though so while the model fits repeatable observations it's a stretch perhaps to say it accurately describes the world. Einstiens thought experiment may have been discredited as a proof, but his core reservation about uncertainty has remained a live issue wouldn't you agree?

Professor_Fink

democrates wrote: »

Quantum theory is not a toe though so while the model fits repeatable observations it's a stretch perhaps to say it accurately describes the world.

It does accurately describe the world. We have not yet observed a system that differed noticably from quantum mechanical predictions. The reason we know that there is a problem is because we know that there is a regime where GR and quantum mechanics become incompatible, but we have not yet been able to make good measurements in this regime (i.e. quantum gravity), and it will likely be a long time before we can.

democrates wrote: »

Einstiens thought experiment may have been discredited as a proof, but his core reservation about uncertainty has remained a live issue wouldn't you agree?

No I wouldn't. The issue of local hidden variables has been firmly settled by the observed violations of Bell's inequality. It literally proves there is no hidden value which predicts the outcome of experiments. There are a number of loopholes, and one in principle can never be closed, but they are very artificial. Hidden variables theories have basically been consigned to the dustbin.

democrates

Professor_Fink wrote: »

It does accurately describe the world. We have not yet observed a system that differed noticably from quantum mechanical predictions. The reason we know that there is a problem is because we know that there is a regime where GR and quantum mechanics become incompatible, but we have not yet been able to make good measurements in this regime (i.e. quantum gravity), and it will likely be a long time before we can.

Ok when you first mentioned 'the world' I took it as shorthand for the universal set of reality, but it looks like you meant the expanding set of our observations.

My reservation was about the following: While common sense tells us that a TOE must exist for the universal set of reality and the set of human observations has continued to expand, it still takes a leap of faith to assert that those sets will reach equality. The theory that they will is plausible, but it is not something that has been proven by the scientific method. Forgive the pedantry!

Professor_Fink wrote: »

No I wouldn't. The issue of local hidden variables has been firmly settled by the observed violations of Bell's inequality. It literally proves there is no hidden value which predicts the outcome of experiments. There are a number of loopholes, and one in principle can never be closed, but they are very artificial. Hidden variables theories have basically been consigned to the dustbin.

Well again hidden variables is a specific attempt at reconciliation, Einstiens general position was that quantum theory is incomplete. The fact that Tim Palmer is offering an idea he believes may complete quantum theory (and has attracted much interest) surely suggests that while the battlefront may have moved on the Einstien/Bohr war so to speak is very much alive.

Professor_Fink

democrates wrote: »

My reservation was about the following: While common sense tells us that a TOE must exist for the universal set of reality and the set of human observations has continued to expand, it still takes a leap of faith to assert that those sets will reach equality. The theory that they will is plausible, but it is not something that has been proven by the scientific method. Forgive the pedantry!

Well, a theory of everything in the sense you describe is impossible. If our universe exists as a one of several non-interacting regions of some larger system, then we will never and can never know (as by definition they are not interacting).

democrates wrote: »

Well again hidden variables is a specific attempt at reconciliation, Einstiens general position was that quantum theory is incomplete.

Hidden variables isn't a specific attempt, but rather a class of theory. You have the uncertainty principle (which makes sense when you take the time to actually think about what it says), or you don't. If you don't, then by definition you have a hidden variables theory. Whether these variables are local or global is still open, but by ruling out an uncertainty principle you are saying that these observables do have definite values. Einstein was horrified at the idea of strong non-local correlations (i.e. the EPR argument) which means the idea of non-local hidden variables would have horrified him even more than quantum mechanics. Bell's theorem rules out ALL local hidden variables theories.

democrates wrote: »

The fact that Tim Palmer is offering an idea he believes may complete quantum theory (and has attracted much interest) surely suggests that while the battlefront may have moved on the Einstien/Bohr war so to speak is very much alive.

The Einstein/Bohr debate is finished and quantum mechanics stands confirmed by repeated experiment to an unprecedented degree. There are still open questions about what happens at the interface of general relativity and quantum mechanics, but this is very far removed from the area of the Einstein/Bohr arguments. I don't really know anything of Tim Palmer, and frankly don't have the time to read the paper. There are a huge number of foundations papers published every year, but that is not to be taken as evidence that quantum mechanics is wrong, as they are largely aimed at shedding light on why quantum mechanics is the way it is, rather than trying to disprove it (as many a man has tried and failed). I don't personally hold much regard for New Scientist after reading some articles where the research reported on was patently wrong. Rob Spekkens who is quoted in the article is a smart guy though, and I do have a lot of respect for him. Still his comments seem rather bland and since it's not clear to me he actually read Palmer's paper, I'm not going to read much into them.

democrates

I think you've hit the nail on the head there, it's regrettable that New Scientist seem to be going for headlines and circulation at the expense of accuracy. A lot of readers would be like myself, non-experts outside the field but are fascinated nonetheless and periodically cast an eye for an update.

I ran with the New Scientist article assuming it reflected the state of play and would be none the wiser if you hadn't taken the time to clarify (even though it was clear I only had a hazy grasp of the topics), so many thanks for that it's much appreciated. Even though I'm the only one engaging directly here a lot more people read these threads than post in them so you've likely achieved far more than it may seem.

Inti

democrates wrote: »

Article in New Scientist titled "Can fractals make sense of the quantum world?"

Royal Society Paper at arXiv titled "The Invariant Set Hypothesis: A New Geometric Framework for the Foundations of Quantum Theory and the Role Played by Gravity"

Tim Palmer outlines a thought provoking model based on the idea that in a chaotic system the invariant set is a fractal, by applying this to the universe he posits that quantum theory is indeed incomplete, but may be so simply due to the alleged fractal nature of the universe - ie the necessary resolution is not being applied to match the fine fractal detail. He believes that 'spooky' effects may in fact be explained by this model which allows for infinite resolution but is ultimately deterministic.

Personally I like the fractal idea, I've never been comfortable with the notion of an indivisible particle - everything is made of something.

that is an interesting article in newscientist.

what do you think the Bohr-Einstein debate is about? i read some different things, but they seem to disagree.

Professor_Fink

Inti wrote: »

that is an interesting article in newscientist.

what do you think the Bohr-Einstein debate is about? i read some different things, but they seem to disagree.

The Einstein-Bohr debates with puppets:

http://blogs.discovermagazine.com/cosmicvariance/2009/12/01/bohr-einstein-puppies-puppets/

Inti

thank you.

i was interested in your opinion.

the video, and the majority of the comments on it, seem to think it's not over.

why do you?

Professor_Fink

Inti wrote: »

thank you.

i was interested in your opinion.

the video, and the majority of the comments on it, seem to think it's not over.

why do you?

The video seemed to make it pretty clear that the observed violation of Bell inequalities settled the debate once and for all. It is certainly the EPR gedanken experiment actually works. Einstein didn't like the idea of superluminal effects, but actually that's not what is happening. There is no signalling with entanglement: it can never be used on it's own to transmit a message.

Also, I suspect the answer to that last part is probably that I know more about quantum mechanics than random internet commenters.

democrates

Professor_Fink wrote: »

Also, I suspect the answer to that last part is probably that I know more about quantum mechanics than random internet commenters.

That sounds like a lyric from this (explicit lyrics) :cool:

Professor_Fink

democrates wrote: »

That sounds like a lyric from this (explicit lyrics) :cool:

Sorry, I know that was probably a bit obnoxious, but I've had a long day.

Inti

Professor_Fink wrote: »

The video seemed to make it pretty clear that the observed violation of Bell inequalities settled the debate once and for all. It is certainly the EPR gedanken experiment actually works. Einstein didn't like the idea of superluminal effects, but actually that's not what is happening. There is no signalling with entanglement: it can never be used on it's own to transmit a message.

Also, I suspect the answer to that last part is probably that I know more about quantum mechanics than random internet commenters.

first, don't worry about your observation - it's well noted. i am thinking (wild guess) that you are a teacher of these things, so i hope to learn something.

i dont think that just mentioning it briefly in closing was "making it pretty clear". he said "out of the scope of this video", and it's another story.

when i made the comment on the video, i mean the speaker doesn't seem to think it's over, not merely from the comments. it was meaning that the video wasn't a good source, imo, to make your point. i've read/heard from other physicists as well as him.

i'd like some better ones, if you know any.

what is the parameter suggested by EPR?

what were mr einstein's other complaints?


also, just to be sure, you say "bohr-einstein debate", but do you mean something bigger? i dont think many people think that bohr made any points at all, let alone "win". the video you linked sure agrees with them.

Professor_Fink

Inti wrote: »

first, don't worry about your observation - it's well noted. i am thinking (wild guess) that you are a teacher of these things, so i hope to learn something.

Some teaching, mostly research.

Inti wrote: »

i dont think that just mentioning it briefly in closing was "making it pretty clear". he said "out of the scope of this video", and it's another story.

Fair enough.

Inti wrote: »

when i made the comment on the video, i mean the speaker doesn't seem to think it's over, not merely from the comments. it was meaning that the video wasn't a good source, imo, to make your point. i've read/heard from other physicists as well as him.

I only posted it as a summary of the debates.

Inti wrote: »

i'd like some better ones, if you know any.

what is the parameter suggested by EPR?

what were mr einstein's other complaints?

Basically Einstein simply didn't like quantum mechanics. He thought it couldn't be an accurate representation of reality. A lot of this is down to the particular view of quantum mechanics that was prevalent at the time, where 'measurement' events caused the wave function to collapse instantaneously. This would seem to be a violation of relativity, since it would appear to suggest effects traveling faster than light.

It turns out this isn't necessarily what happens, but whether it is or isn't is essentially untestable.

The EPR thought experiment imagined preparing to particles in a uniquely quantum mechanical state, and then making an individual measurement. The measurements will always be consistent. Einstein suggested that this was a sign quantum mechanics was wrong. John Bell subsequently derived an inequality that quantum mechanics violates, but local theories do not. Subsequent experiments have confirmed that these inequalities are violated.

So, Einstein was wrong.

Inti wrote: »

also, just to be sure, you say "bohr-einstein debate", but do you mean something bigger? i dont think many people think that bohr made any points at all, let alone "win". the video you linked sure agrees with them.

Well, ohr didn't give perfect answers, and actually managed to convince people with a flawed argument, but thanks to Bell, we have a resolution to the debate.

democrates

Professor_Fink wrote: »

Sorry, I know that was probably a bit obnoxious, but I've had a long day.

No apology necessary we're all human

Besides, looking around this world, too often charismatic chancers get to sway opinion because they sound so sure of what they're saying while those who know better are too polite to interject or are bullied into silence.

"All that is required for evil to triumph is that good men do nothing".

The consequences of false belief are so far reaching that we really need to draw clear lines between leaps of faith and results from the scientific method. By having this debate about what theories are supported by what experimental results, readers get to sharpen their ability to think critically. The challenge remains to package this kind of brain training for secondary education using accessible subject matter, I don't think it's given a high enough priority.

Inti

democrates -
Besides, looking around this world, too often charismatic chancers get to sway opinion because they sound so sure of what they're saying while those who know better are too polite to interject or are bullied into silence.

"All that is required for evil to triumph is that good men do nothing".

The consequences of false belief are so far reaching that we really need to draw clear lines between leaps of faith and results from the scientific method. By having this debate about what theories are supported by what experimental results, readers get to sharpen their ability to think critically. The challenge remains to package this kind of brain training for secondary education using accessible subject matter, I don't think it's given a high enough priority.

very well said. i take it the first part is about bohr vs einstein in personality?

Professor_Fink wrote: »

I only posted it as a summary of the debates.

understood.

Professor_Fink wrote: »

Basically Einstein simply didn't like quantum mechanics. He thought it couldn't be an accurate representation of reality. A lot of this is down to the particular view of quantum mechanics that was prevalent at the time, where 'measurement' events caused the wave function to collapse instantaneously. This would seem to be a violation of relativity, since it would appear to suggest effects traveling faster than light.

ok, but i don't know anyone who "likes" qm. he said it was incomplete. i don't know anyone who says it is "complete". that sounds like he was right to me. (again, i'm not talking about "people on the street"; i mean in the literature)

i agree about what you said on the philosophy of the time. " instantaneous wave function collapse" is still an outstanding problem, afaik. the probability wave and the measurement problem are parts too.

Professor_Fink wrote: »

It turns out this isn't necessarily what happens, but whether it is or isn't is essentially untestable.

that sounds a whole lot like "qm predicts something that is untestable". that is another reason to say "incomplete".

Professor_Fink wrote: »

The EPR thought experiment imagined preparing to particles in a uniquely quantum mechanical state, and then making an individual measurement.

this gets closer to answering my question about which parameter.

Can Quantum-Mechanical Description of Physical Reality Be Considered Complete? http://www.drchinese.com/David/EPR.pdf


first, let's use their (EPR) definition of "incomplete": every element of the physical reality must have a counter-part in the physical theory. i agree with that as a goal. as few of blind, untestable assumptions as possible.

now they start with a state and the wavefunction, as you said, and then assign an operator to momentum; remind us that it is real, and that qm says that we can not, even in principle, know the precise momentum and position at the same time.

then, he shows that this is possible. he knew a bit about the photoelectric effect, and that the position of an electron could be known in the detector, and based on knowing the energy of a photon, we could know the momentum of the electron at the same time (or of the collapsed photon). this was not measurable at the time, it was all a gedanken debate.

this argument between them was dominated by the philosophy-math that was agreed upon in copenhagen (without einstein and others present), which was centered around the uncertainty principle. there are other parameters and issues, as they say in the paper, but it's enough to show that the philosophy had a hole in it - that is less than complete.

as you agreed, nobody (including historical specialists) thinks that bohr really made any sound points, let alone 'win' the debate. certainly, no one would allow a theory to use a postulated abstract math to prove itself. it must tie into existing reality / theory too. the only reason bohr got away with it, was because it was pure gedanken - no one could stop him from saying "no look, there is is behind you!", when referring to uncertainty.

i think this thing is like an urban legend now, because i have not found a direct link to bell, to which you point, supposedly making einstein wrong.

bell is commenting on bohms' theory, and does not address momentum/postition directly, afaik. i believe they use polarization or spin? (the experiments that are supposed to prove this) bell does show that there can be no hidden variables within quantum mechanics. epr says nothing about "hidden variables". bell himself said that doubted he had delivered a 'knock out blow', and did not like qm, or think it was complete.

"More plausible to me ... The wave functions would prove to be a provisional or incomplete description of the quantum-mechanical part, of which an objective account would become possible.

Bell also criticized the standard formalism of Quantum Mechanics on the grounds of lack of physical precision[5]

He remained impressed with Bohm's hidden variables as an example of such a scheme and he attacked the more subjective alternatives such as the Copenhagen interpretation. [10]

"It is difficult for me to believe that quantum mechanics, working very well for currently practical set-ups, will nevertheless fail badly with improvements in counter efficiency ..."[11]

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

of course, my not finding it doesn't prove anything. does anyone have a link or citation of a bell inequality done on momentum/position?

Professor_Fink

Inti wrote: »

ok, but i don't know anyone who "likes" qm. he said it was incomplete. i don't know anyone who says it is "complete". that sounds like he was right to me. (again, i'm not talking about "people on the street"; i mean in the literature)

I do! Actually, I know of virtually no serious physicist who has any doubts about the validity of quantum mechanics. And I know a lot of physicists.

I suspect the problem is stemming from the 'literature' you are reading. Philosophers get themselves tied up in knots over quantum mechanics, but physical reality trumps a well reasoned argument any day!

Inti wrote: »

i agree about what you said on the philosophy of the time. " instantaneous wave function collapse" is still an outstanding problem, afaik. the probability wave and the measurement problem are parts too.

It really isn't. It's essentially the same as with a classical probability distribution. If two boxes are either box empty or both full, looking at one tells you instantaneously about the state of the other. Quantum mechanics is a bit more sophisticated, but it is an analogues effect. You certainly cannot use it to signal, as Einstein was worried.

Quantum mechanics is really well understood at this point. It is simply that people fall into philosophical arguments over the interpretation, and that simply confuses the issue.

Inti wrote: »

that sounds a whole lot like "qm predicts something that is untestable". that is another reason to say "incomplete".

That's not at all true. It is that different philosophical interpretations are untestable, but equally, they are pretty meaningless. The physical theory is testable, and is in fact the most accurately confirmed theory of reality we have ever had. You seem to be conflating philosophy with physics.

Inti wrote: »

first, let's use their (EPR) definition of "incomplete": every element of the physical reality must have a counter-part in the physical theory. i agree with that as a goal. as few of blind, untestable assumptions as possible.

now they start with a state and the wavefunction, as you said, and then assign an operator to momentum; remind us that it is real, and that qm says that we can not, even in principle, know the precise momentum and position at the same time....

The problem is that EPR try to force physical theories to be local, and as it turns out, they aren't. There are no local hidden variables (as shown by observed violations of Bell's inequalities).

Inti wrote: »

i think this thing is like an urban legend now, because i have not found a direct link to bell, to which you point, supposedly making einstein wrong.

Eh, Bell's inequalities are a measure of non-locality. Einstein was pushing the idea that any physical theory had to be local. Bell's inequalities are violated when the experiments are done. Hence, QM is correct and the EPR paradox isn't a paradox.

Inti wrote: »

bell is commenting on bohms' theory, and does not address momentum/postition directly, afaik. i believe they use polarization or spin? (the experiments that are supposed to prove this) bell does show that there can be no hidden variables within quantum mechanics. epr says nothing about "hidden variables". bell himself said that doubted he had delivered a 'knock out blow', and did not like qm, or think it was complete.

Bohm came much later. It doesn't matter what observables you pick as long as the operators don't commute. People use spin or polarization more often as they are finite dimensional systems, where as position and momentum are continuous variables. The same arguments hold for both.

democrates

Inti wrote: »

i take it the first part is about bohr vs einstein in personality?

I meant generally, from religious fundamentalism to political ideology, it certainly wasn't directed here