Who Applies The Operator?

[Joscha]

I was wondering about a question in qm:
Who can apply the operator on a wave function to measure an observable? Is it only granted to human beings, which can't apparently not right, because we measure with particular devices or can "everything" measure? If so, wouldn't it implies that there is a permanent measurement?
As you can see, I'm a kind of confused. I'd be glad about some help!

[Fredrik]

Operators are just functions. They're mathematical objects, not things that someone has to "apply". The operators you're interested represent measuring devices. There are many other threads that discuss what sort of physical system can be considered a "measuring device".

[tom.stoer]

Who can apply the operator on a wave function to measure an observable?
I think this is missleading: An operator representing an observable (like the Hamilton operator H for the energy E) does not tell you how to measure the observable experimentally. Measuring devices and operators have nothing to do with each other.

[Fredrik]

I think this is missleading: An operator representing an observable (like the Hamilton operator H for the energy E) does not tell you how to measure the observable experimentally. Measuring devices and operators have nothing to do with each other.
I think the claim in the second sentence is too strong. Observables can (and should) be defined as equivalence classes of measuring devices, as explained on the first three pages of Araki (http://books.google.com/books?id=VpVmi5iyaYoC&lpg=PP1&pg=PA1#v=onepage&q&f=false). Those equivalence classes are the real-world "things" that are represented mathematically by self-adjoint operators in the theory.

Joscha: Here's another way of saying what you need to hear: If f is a state vector (=wavefunction), and A an operator representing an observable, Af doesn't represent the state after a measurement of A. So "applying the operator" isn't the mathematical representation of performing the measurement.

[arkajad]

Applying the operator can be related to the collapse. But collapse is usually not treated in textbooks yet. Textbooks still rely on the old "axioms" due to von Neumann, and then refined in axiomatic algebraic approaches such as in Jauch and Araki. But this situation may well change in the coming years.

[tom.stoer]

I think the claim in the second sentence is too strong. Observables can (and should) be defined as equivalence classes of measuring devices, as explained on the first three pages of Araki (http://books.google.com/books?id=VpVmi5iyaYoC&lpg=PP1&pg=PA1#v=onepage&q&f=false). Those equivalence classes are the real-world "things" that are represented mathematically by self-adjoint operators in the theory.

A measuring device measures an observable - fine. But neither does the measuring device tell you how the operator looks like, nor does the operator tell you how to construct and use the measuring device!

Example: the momentum operator is just -id/dx; how do you construct a measuring device based on this information?

[arkajad]

p=-id/dx is the canonical momentum. Yes, it is a hermitian operator, so it is usually called an "observable". But, when, for instance, a vector potential is present, it is gauge-dependent, therefore it is not an observable. Kinetic momentum m\dot{\mathbf{x}}=\mathbf{p}-(e/c)\mathbf{A} is an observable. It can be measured, for instance, by a ballistic pendulum.

[Fredrik]

A measuring device measures an observable - fine. But neither does the measuring device tell you how the operator looks like, nor does the operator tell you how to construct and use the measuring device!

Example: the momentum operator is just -id/dx; how do you construct a measuring device based on this information?
The only option I see to having a separate axiom for each observable (an axiom that explicitly specifies the corresponding operator) is to only allow observables that correspond to symmetries of spacetime. I don't have all the details clear in my head, so I can't elaborate well enough to leave you satisfied with the answer. I'll just say that I think that all the commutation relations can be obtained from the theory of representations of Lie groups and Lie algebras, and that the question of (for example) what specific operator should represent momentum, is completely determined by a choice of a representation of the relevant algebra. (I still have a lot to learn before I can explain all the details, or even be sure that I'm making sense).

[arkajad]

When there are external fields, for instance a vector potential, there is no translational symmetry. And yet kinetic momentum (but not the canonical momentum that relates to "presymmetry") is an observable that has a well defined operation meaning.

[tom.stoer]

p=-id/dx is the canonical momentum. Yes, it is a hermitian operator, so it is usually called an "observable". But, when, for instance, a vector potential is present, it is gauge-dependent, therefore it is not an observable. Kinetic momentum m\dot{\mathbf{x}}=\mathbf{p}-(e/c)\mathbf{A} is an observable. It can be measured, for instance, by a ballistic pendulum.
All what you are writing is well-known but it misses the essential point.

The construction of an operator (i.e. using space-time symmetry considerations) and the construction of a measuring device do not anything in common. Whether there is a physical observable, whether there are gauge fields present and one has to distinguish between canonical and kinematical momentum does by no means tell you anything regarding the construction of the measuring device.

If you have a physical observable (in the strict Dirac sense i.e. w/o further gauge degrees of freedom - which can be decided purely within the formalism of QM) you knwo that there is an observable which you can measure in principle, but you don't know how to do it in practice.

Again: the momentum -id/dx is a well-defined physical observable (in the absence of gauge fields) but writing down -id/dx doesn't mean that you know how the device will look like.

[arkajad]

You have missed the essential point: when gauge fields are present, and they are present everywhere around us and all the time, then the canonical momentum is not an observable (no operational procedure exists) , while kinetic momentum is, it can be measured by a ballistic pendulum.

[Demystifier]

If so, wouldn't it implies that there is a permanent measurement?

In a sense, you are right. Different subsystems interact most of the time, and interaction is described by an interaction Hamiltonian which is an OPERATOR. In most cases the interaction involves a large number of the degrees of freedom, in which case the interaction is usually referred to as DECOHERENCE.

Humans play a secondary role here. They have an apparent ability to "choose" the interaction they want, which corresponds to a measurement of the observable they want.

[arkajad]

Hamiltonian interaction is just an interaction, not a measurement. With Hamiltonian interactions nothing "decoheres". You have just an ordinary, reversible evolution

"Choice" is also not important. The universe is measuring itself all the time without human beings. What human beings do is: they interpret.

[Demystifier]

Hamiltonian interaction is just an interaction, not a measurement. With Hamiltonian interactions nothing "decoheres". You have just an ordinary, reversible evolution

"Choice" is also not important. The universe is measuring itself all the time without human beings. What human beings do is: they interpret.
I agree, but it does not contradict what I said.

[tom.stoer]

You have missed the essential point: when gauge fields are present, and they are present everywhere around us and all the time, then the canonical momentum is not an observable (no operational procedure exists) , while kinetic momentum is, it can be measured by a ballistic pendulum.

I know that very well, but that is not the essential point!

You can take any observable you like, e.g. p, x, H, J as an example in order to avoid the problem with gauge fields.

The essential point is that the observable (p, x, H, J, ...) never tells you how to construct a measuring device. That's the point menitioned in the original post. An operator does not "measure" the observable in a physical sense; it does not represent the measuring device.

[arkajad]

An operator can represent a measuring device. For instance the kinetic momentum represents pretty well the ballistic pendulum for certain measurements. An appropriate function of the position operator can represent pretty well a particle location detector.

An operator doesn't tell us how to construct anything, because linear operators don't speak. But looking at a given operator sometimes we can find out what kind of a physical operation it may correspond to. For some operators it may be straightforward, for other operators difficult or impossible. But usually we have a converse need: we have an experimental arrangement and we want to find operators that can be used to simulate this arrangement mathematically. Usually not so many options are there to chose from.

[tom.stoer]

Say you have a free electron, a charged particle in a Pauli trap or something like that. Now using the position operator x how do you measure the position? Using p² how to you measure the kinetic energy?

[arkajad]

I am not measuring the position with an operator. I need a physical device. Tell me which is your physical device that measures the position of your electron, describe how it does it, and I will try to find the operator that will simulate the behavior of this device when coupled to your electron.

[Careful]

Say you have a free electron, a charged particle in a Pauli trap or something like that. Now using the position operator x how do you measure the position? Using p² how to you measure the kinetic energy?
Hehe, good remark :smile: First of all, I am against the viewpoint of observable algebra's like C* or Von Neumann algebra's since they make it appear as if when an operator is self adjoint, we should be able to ''measure it''. I also happen to be convinced that $x,p$ are actually never ever measured (certainly not p). Going into this issue in depth would lead me to several pages of writing (which I have no time for), but I definetly feel that people like Wigner, Pauli and more recently Penrose have said the most intelligent things about this. Physicists are actually very dismissive about these considerations since they all feel it is metaphysical while I claim it is very physical: it constitutes a theory for the direct observations we make all the time.

[Careful]

I am not measuring the position with an operator. I need a physical device. Tell me which is your physical device that measures the position of your electron, describe how it does it, and I will try to find the operator that will simulate the behavior of this device when coupled to your electron.

Now, that's the second time you do this! If you do somehow think that your measurements are not the results of the ordinary born postulate applied to well defined operators: please, do tell us what they are and how you compute them in ordinary quantum theory. Or if you are saying that you have other operators in mind : do define them (which will be terribly difficult since they are all nonlocal) and compute the consequences. Show me one paper where you did this.

I mean your type or reasoning is of that of an engineer who wants a ''hands on'' explanation why his apparatus is going to measure some nonlocal observable without actually understanding in detail the local microscopic physics behind it (your only justification is that it ''works''). You are correctly convinced that that an apparatus ''preselects'' an observable for you: but that begs the question, WHY is that?? Nothing in QM tells you that some physical system selects it's observables... so there is -as you suggest- a preferred local observable in nature from which one ought to construct composite non-local observables. But this is a daunting task! I begs the question: by what intrinsic procedure are these observables constructed?? It must be something outside quantum mechanics which does this for you.

[arkajad]

If have, say an electron, and if you have a photographic plate that is sensitive to passing electrons, you can approximately simulate the behavior of this plate using a function of a position operator. I will not refer you to any paper because you insist on "how you compute them in ordinary quantum theory". I do not know how to do it in "ordinary quantum theory". And going beyond "ordinary quantum theory" is not being encouraged on this particular forum. All I can say is that in the not so realistic limit of "instant activation of the sensitivity of the plate" the usual Born's prescription for calculating the probabilities of registering the passing electron is approximately correct.

[Careful]

If have, say an electron, and if you have a photographic plate that is sensitive to passing electrons, you can approximately simulate the behavior of this plate using a function of a position operator. I will not refer you to any paper because you insist on "how you compute them in ordinary quantum theory". I do not know how to do it in "ordinary quantum theory". And going beyond "ordinary quantum theory" is not being encouraged on this particular forum. All I can say is that in the not so realistic limit of "instant activation of the sensitivity of the plate" the usual Born's prescription for calculating the probabilities of registering the passing electron is approximately correct.
See, my previous post, I have extended it meanwhile. I am rather sympathetic to what you say here and people who think this is not worthwhile discussing can go and f*ck off :smile: I think we would both agree that you need to solve this problem outside ordinary QM but where we disagree is on how to do it: you seem to be thinking about extending it in Piron's way by generalizing away from Hilbert space to include classical systems, right?

[arkajad]

No. Not the Piron's way. Something along the lines of this (http://arxiv.org/abs/hep-th/9407157) way.

[Careful]

No. Not the Piron's way. Something along the lines of this (http://arxiv.org/abs/hep-th/9407157) way.
Ok, I will read it carefully this evening although I am convinced that considering classical apparati is certainly not the way to go. So I will respond somewhere tomorrow, I have different things to do now.

[tom.stoer]

I am not measuring the position with an operator. I need a physical device.
Sometimes it's helpful to take note what oothers have written in their posts. If you look at my post you will find numerous claims that an operator (observable) neither is nor describes a measuring device. Unfortunately you decided to ignore this completely and to start an irrelevant discussion regarding gauge fields.
Then you claimed that "an operator can represent a measuring device. For instance the kinetic momentum represents pretty well the ballistic pendulum for certain measurements. An appropriate function of the position operator can represent pretty well a particle location detector".
After my question how to measure the position using the operator x you told me that this does not work (of course it doesn't work but I never claimed this). You now want me to "tell you a physical device that measures the position of your electron, describe how it does it, and I will try to find the operator". It is ridiculous to modify the problem an solve something that has not been asked for.

Coming back to the question asked in post #1 "Who can apply the operator on a wave function to measure an observable?"

As I said in my first posts, applying an operator to a wave function does not measure the observable. Multiplying a wave function in position space with x does not measure the position. This procedure does not say anything regarding a measurement. OK?

[arkajad]

I was simply replying to your comments.
As I said in my first posts, applying an operator to a wave function does not measure the observable.

Of course it does not. What measure is a physical device, not an operator. So, we are in agreement.

Multiplying a wave function in position space with x does not measure the position.

Here we are in agreement again.

[QUOTE]This procedure does not say anything regarding a measurement. OK?[/QIOTE]

Other procedures do. OK.

[Careful]

No. Not the Piron's way. Something along the lines of this (http://arxiv.org/abs/hep-th/9407157) way.
Ok, I read the first 8 pages which is I guess sufficient to get the idea (actually I immediatly understood what you did on page 3 which is enough since you claim that's the main result). Right, so what do I think about this kind of generalization of GRW? First of all, you violate a property I hold very dear in physics, which is locality. Indeed for an inhomogeneous medium the Lambda term and the Hamiltonian do not commute anymore so that your born rule becomes nonlocal. That is, the probability of a measurement at a depends upon amplitudes which correspond to an event at b. That is pretty bad although it would not pose any practical problem if you restrict your setup to sufficiently small length scales. For the universe however, it would be a disaster. Furthermore, you *have* to consider an inhomogeneous medium since you know you cannot explain the measurement problem if you start from microscopic physics. Hence, what I missed was an equation for the medium !! Clearly, it must depend upon matter sources and so on. But then, this would provide a kind of classical background noise, which must probably persist to exist in the particle vacuum. Does that not give you an extra cosmological constant problem?? Also, would your medium not contradict the michelson morely experiment? All these realistic measurement theories run into terrible diffuculities when you try to generalize this even to special relativity, let along general relativity. These are the only comments I make from a physical point of view; from the philosophical point of view I of course totally disagree with what you try to do, but everybody has the right to his own opinions.

[tom.stoer]

No. Not the Piron's way. Something along the lines of this (http://arxiv.org/abs/hep-th/9407157) way.
I started to read that paper; it looks non-standard so it requires some care to comment it here. Anyway - I have the feeling that there's no way to save "reality" in qm, even if we accept violation of locality. I can't proof this, but I think we are simply fooled by the idea to transport our classical concepts to the quantum world.

But of course new ideas are always welcome.

[Careful]

Anyway - I have the feeling that there's no way to save "reality" in qm, even if we accept violation of locality. I can't proof this, but I think we are simply fooled by the idea to transport our classical concepts to the quantum world.

I think your feeling is wrong but your conclusion is right. There is no way you can prove such thing, but that is not really the issue. The point is that you cannot formulate a natural theory which would lead to the same predictions. So Ockham's razor decides here, not some silly no-go theorem.

[tom.stoer]

I think that there are some indications that a proof could be possible. The Kochen-Specker theorem shows that QM is not simply a "classical statistical theory". The Bell theorem rules out a certain class of "local hidden variable theories".

In the end you are right: once one has proved that a certain class of "simple" theories has been ruled out, more complicated theories are not forbidden but become unreasonable due to Ockhams razor. The question is what is the border line between "simple" and "too complicated" theories.

[Careful]

I think that there are some indications that a proof could be possible. The Kochen-Specker theorem shows that QM is not simply a "classical statistical theory". The Bell theorem rules out a certain class of "local hidden variable theories".

In the end you are right: once one has proved that a certain class of "simple" theories has been ruled out, more complicated theories are not forbidden but become unreasonable due to Ockhams razor. The question is what is the border line between "simple" and "too complicated" theories.

Yes, that is a deep debate. For example, a resolution to the measurement problem will complicate QM seriously too. So, it might very well be that a deeper spitting in QM actually opens the door again for nonlocal realist theories. The theorems you mention are peanuts, I could write in 2 months a paper destroying each of those theorems to pieces. Arguing in this way really makes no sense, it expresses more the limited imagination of the beholder than the impossibility of the construction. Take my word for it.

[arkajad]

The theorems you mention are peanuts, I could write in 2 months a paper destroying each of those theorems to pieces.

I do not think that the theorems will be destroyed this way. They will survive, I am sure. But they may become quoted less often :).

[Careful]

I do not think that the theorems will be destroyed this way. They will survive, I am sure. But they may become quoted less often :).
Well, I was speaking about scientifically destroying them, not about some sociological phenomenon where some load of dopes would still cite these things to dress up as intellectuals :approve: I would never ever use a no-go theorem in any discussion because I understand the distinction between a mathematical theorem and physics by which I certainly do not mean to imply that these no-go theorems are not important. On the contrary, they stretch our imagination and liberate us from prejudices !

[arkajad]

On the contrary, they stretch our imagination and liberate us from prejudices !

When we see that some door is closed, what we do? Some people give up, some try to use brute force, some other look for a backyard door or for a hole in the fence. Lovoisier was not a mathematician, he was a chemist, nevertheless he is famous not only for his achievements in chemistry but also for his no-go theorem. He argued against the existence of meteorites with a convincing argument: "stones can not fall from the sky, simply because there are no stones in the sky". And, in a sense, he was undoubtedly right. No one questions that.

[Careful]

When we see that some door is closed, what we do? Some people give up, some try to use brute force, some other look for a backyard door or for a hole in the fence. Lovoisier was not a mathematician, he was a chemist, nevertheless he is famous not only for his achievements in chemistry but also for his no-go theorem. He argued against the existence of meteorites with a convincing argument: "stones can not fall from the sky, simply because there are no stones in the sky". And, in a sense, he was undoubtedly right. No one questions that.
Well, in the puzzle you are interested in, I think you need to liberate yourself entirely from a classical point of view. I understand this feeling very well, you feel there is sh*t in QM but you don't know where precisely. Quantum theory seems so accurately constructed that most people are almost convinced that there is no room for improvement. Likewise, I had a (local) realist period between 2005-2008; that's why I know that all these no-go theorems are a pile of garbage because I did manage to surpass them each. What I did not find was an all embracing theory which had the same explanatory power than QM has. So I resigned my attempt and started to do the opposite: I took quantum theory really seriously. THAT has been the most fruitful excercise of my life since there is indeed sh*t and I found out precisely where (and it is nothing people have ever imagined before).

[tom.stoer]

... I could write in 2 months a paper destroying each of those theorems to pieces. ... Take my word for it.
I am looking forward to you paper - 28.01.2011 on arxiv!

[Careful]

I am looking forward to you paper - 28.01.2011 on arxiv!
Ohw, I am not going to publish those things (Kochen Specker and Bell) for very good reasons. People simply are not interested in it! They will only listen when you are smarter than Einstein and manage to come up with an alternative QFT like theory, which reduces to the old one where the latter has been tested. So that is what I am actually working on. You have no idea how many dishonest people I have met in my life: a typical discussion goes as follows. They claim A : you cannot do that (say demolish Kochen Specker), one month later I would go back to them and show a toy theory which does precisely that. Hmmm would they say, but with this theory, can you violate the Bell inequalities. No, I would say because it was not designed in this way. But then it is worth nothing, they would argue. But ok, i just showed you that A is wrong ! You can bet these same people would repeat A against other students the next day.

Such things are the utmost examples of stupidity; of course, going back to naive realism is not fruitful - but one should have to CORRECT objections against those ideas and not some false pretensions.

[tom.stoer]

Perhaps it would help not to promise to be able to destroy the pillars of QM within a few weeks. But of course I would be very interested ...

[Careful]

Perhaps it would help not to promise to be able to destroy the pillars of QM within a few weeks. But of course I would be very interested ...
I only made this promise once and it was 5 years ago, and yes I was wrong. But what is more devastating, the enthusiasm of a clearly very intelligent and well read person who makes an exaggerated claim and kicks holy houses or the unimaginative sarcasm of a pedantic person who argues by the wrong means ? Think about that! Over the years of course, one gets wiser and calmer. But the difference between the pedantic person and the kicker is that the latter actually learns something. So yeh, I definetly prefer that

[arkajad]

So I resigned my attempt and started to do the opposite: I took quantum theory really seriously.

I would like to see how you deal with the problem of "time of arrival" and track formation if you take QM seriously. How you avoid what you call "classical concepts", like "measurement", "environment", "time", "result, "Planck constant", "Hilbert space", "reference frame". Can you? I am willing to convert myself.

[tom.stoer]

I don't think that it makes sense to stay here for a future discussion. The thread started rather interesting but in the meantime it's main characterictics is adopting the wrong tone.
Bye.
Tom

[Careful]

I would like to see how you deal with the problem of "time of arrival" and track formation if you take QM seriously. How you avoid what you call "classical concepts", like "measurement", "environment", "time", "result, "Planck constant", "Hilbert space", "reference frame". Can you? I am willing to convert myself.
Well, Tom is right in asfar that we should not speak about what may lie in the future: I don't think however that the tone of the discussion got bad. Concepts I would definitely generalize are the notions of Hilbert space and time. I would dismiss ideas about environment. Of course, keepers are Planck constant and reference frame (but you have to be careful what you mean with that). Measurement is the most challenging and it requires a theory of awareness.

Anyhow, to end with a philosophical note: you told me there are three possibilities to walk through the wall (a) give up (b) brute force and (c) look for holes. Well I think you missed the most important one: the royal door which we are completely blind for! (a) is not an option, in case of (b) you might think that knocking your head against the brick wall is going to break it, no way! In the third case, you think like a clever thief, but the wall maker has forseen that you might think the foundations are not that strong and you look for holes, or that you might look for 'soft' bricks. However, if you find the royal door, it means that you have looked beyond the bricks and the paste and have seen patterns which nobody spotted before you. That is the key: there is very little wrong with quantum mechanics, otherwise we would have spotted it already. Likewise, we know something is wrong with QFT and/or gravity, otherwise we would have solved that problem also too. Also, it is very probable that some *physical* idea behind QFT is wrong, otherwise the smart people doing axiomatic QFT would have constructed the foundations long time ago. So, what is *physically* wrong?? It must be something extremely subtle which changes the entire theory. That is the royal door. :smile:

[unusualname]

You are right Careful, it is this http://jbg.f2s.com/quantum2.txt

Go on, ban me physics forum mods, after posting the "solution" to QM whilst allowing deluded people hundreds of posts examining possible classical loopholes in QM experiments.

This is a good test for you no? Is the universe a random automata? It's consistent with all known experimental results.

[Careful]

You are right Careful, it is this http://jbg.f2s.com/quantum2.txt

Go on, ban me physics forum mods, after posting the "solution" to QM whilst allowing deluded people hundreds of posts examining possible classical loopholes in QM experiments.

This is a good test for you no? Is the universe a random automata? It's consistent with all known experimental results.

I am not going to look at this, but let me tell you the following:
(a) in order to comprehend this problem if full depth, you have to think intensly for many years, you definetly need a PhD degree to even start with and you have to be mathematically gifted.
(b) You need ocassionally make phone calls with connections you have in academia, I regularly speak for more than an hour with reputable researchers in my field: my phone bill is huge.
(c) You always need to be crystal clear about your own program: this is not done by posting a sheet of one A4 paper in a doc file. First of all, you will need to explain what you think is wrong, then you need to make the postulates of your theory and third you need to make a few independent consistency checks! At least five of them: for example, if you claim to have a new Quantum theory, you need to show that somehow you can get free QFT out and that at least some renormalized terms of the usual Dyson expansion in interacting theories are recovered. Moreover, you might like to investigate corrections to some well known experiments and make a novel prediction.
(d) You have to hand it in for peer review. No way you can get around that: actually, it would be wise to first offer it for peer review BEFORE you hand it in to the Arxiv or some forum.

These guidelines are mandatory, the path of true discovery is lonely and hard, very hard, even for the gifted people.

[unusualname]

I have probably thought about this more years than you.

And I may have been a better mathematican than you also, but that's not important.

The simplicity of the postulates is deceiving, annihilation and creation is occurring in a probablilstic mayhem here.

Argue scientifically, not ad hominem.

[arkajad]

Measurement is the most challenging and it requires a theory of awareness.

I second that.

[Careful]

I have probably thought about this more years than you.

And I may have been a better mathematican than you also, but that's not important.

The simplicity of the postulates is deceiving, annihilation and creation is occurring in a probablilstic mayhem here.

Argue scientifically, not ad hominem.
I did argue scientifically ! :grumpy: I see nothing in this one sheet which satisfies any of the criteria I mentioned; you do not comprehend that we live in a scientific community which has installed these quality guidelines in order not to waste any time with things which are not valuable at all. I briefly looked at it and your formulae absolutely make no sense whatsoever. For example, you have missed the entirely trivial fact that the demand of Poincare invariance requires infinite dimensional spaces and not finite dimensional ones. There are zillions of such things I could say about your proposal but you would highly likely not understand them. My guess is that you don't even have a bachelor degree in physics or a related field and this is not meant in a pejorative way. Although Einstein had no PhD, he still had his contacts in academia and I am sorry, in the modern times this is not even sufficient anymore.

[Careful]

I second that.
Good, my consciousness just registered that :rofl:

[unusualname]

I did argue scientifically ! :grumpy: I see nothing in this one sheet which satisfies any of the criteria I mentioned; you do not comprehend that we live in a scientific community which has installed these quality guidelines in order not to waste any time with things which are not valuable at all. I briefly looked at it and your formulae absolutely make no sense whatsoever. For example, you have missed the entirely trivial fact that the demand of Poincare invariance requires infinite dimensional spaces and not finite dimensional ones. There are zillions of such things I could say about your proposal but you would highly likely not understand them. My guess is that you don't even have a bachelor degree in physics or a related field and this is not meant in a pejorative way. Although Einstein had no PhD, he still had his contacts in academia and I am sorry, in the modern times this is not even sufficient anymore.

Poincare invariance? What are you you talking about? I won a half share of the University of London award for mathematics in my graduation year, so I think I can ferret out irrelevant nonsense like that.

Do you understand QFT? Do you understand its probabilistic nature? Do you understand the Feynman path integral approach which sums over ALL (ridiculous) possibilities?

[Careful]

Poincare invariance? What are you you talking about? I won a half share of the University of London award for mathematics in my graduation year, so I think I can ferret out irrelevant nonsense like that.

Do you understand QFT? Do you understand its probabilistic nature? Do you understand the Feynman path integral approach which sums over ALL (ridiculous) possibilities?
Well, all I can say then is that the comittee probably was asleep when they granted you that award. The quality of what you write is so low that I can hardly imagine what you say is even 1% of the truth (unless you suffered a complete mental breakdown or so). And why do you think Poincare invariance is not important? It is a fundamental property of relativistic theories and within quantum theory, you do need a (Hilbert) space carrying it's representation. It is irrelevant whether you work here in the path integral formulation or not.

Really, take my advise and visit a shrink or so: talk about your passion and desire to solve a puzzle which you do not even properly comprehend. Focus on other things in life and enjoy it, but give up on things which you cannot possibly reach.

[unusualname]

Well, all I can say then is that the comittee probably was asleep when they granted you that award. The quality of what you write is so low that I can hardly imagine what you say is even 1% of the truth (unless you suffered a complete mental breakdown or so). And why do you think Poincare invariance is not important? It is a fundamental property of relativistic theories and within quantum theory, you do need a (Hilbert) space carrying it's representation. It is irrelevant whether you work here in the path integral formulation or not.

Really, take my advise and visit a shrink or so: talk about your passion and desire to solve a puzzle which you do not even properly comprehend. Focus on other things in life and enjoy it, but give up on things which you cannot possibly reach.

Poincare invariance is less relevant here than Poincare recurrence is to statistical physics (which is about zero relevance). I'll probably have to construct a CUDA simulation of 10^9 states or so to convince you, but the theory is sound. All QFT falls out of the evolution law + randomness if you think about for even a short time.

[Careful]

Poincare invariance is less relevant here than Poincare recurrence is to statistical physics (which is about zero relevance). I'll probably have to construct a CUDA simulation of 10^9 states or so to convince you, but the theory is sound. All QFT falls out of the evolution law + randomness if you think about for even a short time.
Well you can say whatever you want but
(a) there was no evolution law written down in your ''paper''.
(b) no simulations were presented whatsoever.
(c) It is just impossible to recover Poincare invariance from a finite lattice formulation unless your lattice is dynamical itself. 't Hooft has written some nice papers about the breaking of rotation invariance on lattices and so on (in the context of cellular automata).
(d) In order to talk about even just a correspondence with QFT, you would have to define what a particle is. Now, I can imagine that you can simulate such thing like an ordinary classical Klein Gordon equation on a lattice, but no way you are dealing with the problem of an arbitrary number of particles (and no way you solve the measurement problem in this approach).
(e) the dynamics of QFT is defined on an infinite dimensional space (mandatory by Poincare invariance), no way that you manage to get something like that out from a finite simulation + some noise.

So, go home, learn some proper physics, and do your job or follow my advise and look for a good shrink.

[unusualname]

Well you can say whatever you want but
(a) there was no evolution law written down in your ''paper''.
(b) no simulations were presented whatsoever.
(c) It is just impossible to recover Poincare invariance from a finite lattice formulation unless your lattice is dynamical itself. 't Hooft has written some nice papers about the breaking of rotation invariance on lattices and so on (in the context of cellular automata).
(d) In order to talk about even just a correspondence with QFT, you would have to define what a particle is. Now, I can imagine that you can simulate such thing like an ordinary classical Klein Gordon equation on a lattice, but no way you are dealing with the problem of an arbitrary number of particles (and no way you solve the measurement problem in this approach).
(e) the dynamics of QFT is defined on an infinite dimensional space (mandatory by Poincare invariance), no way that you manage to get something like that out from a finite simulation + some noise.

So, go home, learn some proper physics, and do your job or follow my advise and look for a good shrink.

If you were sure of your arguments you wouldn't resort to ad hominem.

The debates between people like yourself go on here for years and years, and finally presented with a conclusion you resist, it is understandable but disappointing.

The measurement problem is dealt with by invoking human attributes and otherwise is restricted to stable macroscopic remnants in the universe - ooh - that's controversial.

[Careful]

If you were sure of your arguments you wouldn't resort to ad hominem.

The debates between people like yourself go on here for years and years, and finally presented with a conclusion you resist, it is understandable but disappointing.

The measurement problem is dealt with by invoking human attributes and otherwise is restricted to stable macroscopic remnants in the universe - ooh - that's controversial.
I am sure of my arguments because I tried some far less naive ideas myself! And no, I don't go ad hominem, you have no idea how sad it is to see someone claiming to have solved the deepest problem in nature and comes up with a lousy A4 sheet full of rubbish. You know, I do have a cousin who suffers severly from bipolar and who has been in a manic phase for such a long time that psychiatrists feared for his life even (you can die of exhaustion here you know). Well, we did not meet for like 15 years and 3 years ago he wrote me a letter with two sheets of paper containing elementary formulae which he thought might be of use for my work. A week later, I called him and politely thanked him for sharing his thoughts with me - we did not speak about it any further.

And no, I am not 'a standard physicsforums-member' as most people who ''know'' me can testify: I have an unusual patience with unconventional ideas and always try to reason with the person. But if I see a case like you, I have to say what I said, for your own good (even if you don't take my word for it).

[unusualname]

It wan't simple when I conceived it, It was argued out over a week with Lubos Motl. I had orginally conceived of a holographic "projection" to retrieve local causality but the model reduced to its seemingly bare simplicity after realising Motl (and others) had the wong understanding of "non-locality" which is only manifest as local causality in nature.

I can't apologise for the the beautiful simplicity of the universe, Wolfram and others had similar models but I assume the reluctance to embrace fundamental randomness and a non-local evolution law kept everyone from making the obvious discovery:

Nature is non-local, non-real (in Einstein's sense) and non-deterministic! who'd have ever thought it!

[Careful]

It wan't simple when I conceived it, It was argued out over a week with Lubos Motl. I had orginally conceived of a holographic "projection" to retrieve local causality but the model reduced to its seemingly bare simplicity after realising Motl (and others) had the wong understanding of "non-locality" which is only manifest as local causality in nature.

I can't apologise for the the beautiful simplicity of the universe, Wolfram and others had similar models but I assume the reluctance to embrace fundamental randomness and a non-local evolution law kept everyone from making the obvious discovery:

Nature is non-local, non-real (in Einstein's sense) and non-deterministic! who'd have ever thought it!
Knowing Lubos' way of dealing with unconventional ideas, he would have dismissed it after one single look at your paper. You use expensive words here, but they don't mean anything, you don't make a coherent sentence! For example, you conceived a ''holographic projection'' to retrieve local causality. What the ****? Local causality simply means that the state of a field at a point is determined by the initial value on any local spacelike slice of the past lightcone. How can you retrieve something that local from a non-local thing like a holographic projection?! And no, nature is appearantly not locally causal and no-one has ever succeed to show a model which recuperates all quantum predictions in this way. The rest doesn't make any sense except for the last line. I think any researcher in quantum gravity would agree on those three statements. So, if the last line were your revolutionary discovery: welcome, you share this opinion with thousands of people.

[unusualname]

Knowing Lubos' way of dealing with unconventional ideas, he would have dismissed it after one single look at your paper. You use expensive words here, but they don't mean anything, you don't make a coherent sentence! For example, you conceived a ''holographic projection'' to retrieve local causality. What the ****? Local causality simply means that the state of a field at a point is determined by the initial value on any local spacelike slice of the past lightcone. How can you retrieve something that local from a non-local thing like a holographic projection?! And no, nature is appearantly not locally causal and no-one has ever succeed to show a model which recuperates all quantum predictions in this way. The rest doesn't make any sense except for the last line. I think any researcher in quantum gravity would agree on those three statements. So, if the last line were your revolutionary discovery: welcome, you share this opinion with thousands of people.

Jesus, until I actually produce the exact form of the evolution Matrix M I guess i'm going to have to put up with this.

M is unitary, it's huge, it's probably a bit more complex than the current Standard Model would suggest, especially since gravity is so much weaker than everything else.

At worst you'll get a toy universe containing some basic particles with this model, with all the probablistic creation and annihilation described in QFT. Any reasonably foresighted person can see that the real universe is not beyond construction.

[Careful]

Jesus, until I actually produce the exact form of the evolution Matrix M I guess i'm going to have to put up with this.

M is unitary, it's huge, it's probably a bit more complex than the current Standard Model would suggest, especially since gravity is so much weaker than everything else.

At worst you'll get a toy universe containing some basic particles with this model, with all the probablistic creation and annihilation described in QFT. Any reasonably foresighted person can see that the real universe is not beyond construction.
Sure, we are all dumb and do not understand your brilliant work which is written by little invisible green men on one sheet of A4. Neither are my comments probably valid that your language is incoherent. Since there is no way of talking to you, since you actually do not show any real work and do not properly react to the many counterarguments I have given so far to you, do the decent thing and work out the ''details'' of your theory. Then, you will have surpassed Garret Lisi in one stroke of genius :biggrin:

[unusualname]

I really don't want to make a fuss. I had a simple honest argument with Motl about the interpretation of the delayed choice quantum eraser and refused to submit to orthodoxy in analysing it.

I came to my conclusions after several days of intense thought, my stumbling along the way is documented in a thread on his blog.

However, once coming to the conclusions, I had no doubt in their correctness and superiority to copenhagen + decoherence. I am not currently in academia so do not have arXiv submission access, however any reasonable person can see my conclusions are important and I really think they have at least the beginnings of an idea which should help us evolve beyond the 1930s philosophy of QM.

[Careful]

I really don't want to make a fuss. I had a simple honest argument with Motl about the interpretation of the delayed choice quantum eraser and refused to submit to orthodoxy in analysing it.

I came to my conclusions after several days of intense thought, my stumbling along the way is documented in a thread on his blog.

However, once coming to the conclusions, I had no doubt in their correctness and superiority to copenhagen + decoherence. I am not currently in academia so do not have arXiv submission access, however any reasonable person can see my conclusions are important and I really think they have at least the beginnings of an idea which should help us evolve beyond the 1930s philosophy of QM.
I give up, your idea of what a reasonable person is supposed to be goes beyond the pale for my taste. As I thought, you did not discuss with Lubos your A4 sheet, try it!

[Borek]

Closed pending moderation.