How do deterministic Bohmian/Pilot Wave Theories Handle These?

[Dmitry67]

Yes, I can. I have to modify the theory of gravity for this, but I have done this already before becoming a Bohm supporter. See ilja-schmelzer.de/glet.

Could you point me to the right place?
So you want to say, that you can define a frame common to the outer and inner space which does not have any singularities?

Also, how the preferred frame is consistent with the Big ang theory? If there is a preferred frame, then there is a (hidden) preferred point in the universe, where preferred frame is in rest to the CMB, right?

 

[Dmitry67]

But my main problem with MWI is that none of the possibilities has anything to do with the wave function. The wave function appears to be some linear combination of them, but every two states |a> and |b> are connected in such a way: |a> = |b> + (|a> - |b>). Thus, this linear decomposition defines no connection at all between the wave function and the particular branch.

yes, I agree with you, but so what? 'branch', like an 'observer', is a meta (nonphysical) structure - some compelx system which can be isolated based on some criteria

P.S. I will read both your articles a little bit later

 

[Dmitry67]

I have a cosmological question to the BM supporters.

What is price per barrel next year?
I mean, it is definitely pre-coded at the time of the Big bang, right :) ? Laplace determinism is valid for any deterministic single=history theory...

 

[Demystifier]

I have a cosmological question to the BM supporters.

What is price per barrel next year?
I mean, it is definitely pre-coded at the time of the Big bang, right :) ? Laplace determinism is valid for any deterministic single=history theory...

I will calculate that when you calculate the probability distribution of prices per barrel next year starting from first principles of QM in the many-world interpretation.

 

[Demystifier]

So your question 'but how MWI explains the frogs?' is like 'I see that chemistry works well, but how chemistry explains the phases of the moon?'

That is a good point. Still, there is a set of physical laws, which are not completely independent, that explain BOTH chemistry and phases of the moon. BI is an attempt to do something similar for BOTH MWI and frogs. Moreover, the encouraging fact is that BI achieves that in a rather simple way.

If you still cannot understand why some people prefer BI over MWI, then you probably don't want to. It is certainly an advantage to be able to understand how other people think. But of course, it is much simpler to say that all other people are crazy, so why bother with their way of thinking anyway ...

 

[Fra]

I see CI, for example, as a modern alchemistry: a description of the QM world based on some magical 'measurement devices' and 'knowledge of an observer about the system'.

MWI get rids of it like modern chemistry get rids of the phases of the Moon. So your question 'but how MWI explains the frogs?' is like 'I see that chemistry works well, but how chemistry explains the phases of the moon?'

My spells doesn't seem to work on Dmitry67, but there is a view that is close to mine, but still slightly more realistic put than I have in mind, and it's sort of an opposite to MWI, that Smolin also mentions in the last chapters in his book "the life of the cosmos".

The last section, which he calls "Einsteins Revenge" mentions a pluralistic universe which instead of multiple universes, considers multiple observers that are interacting. There he suggest that there is no magic separation of observer / observerd, as any separation is valid, any separation is interpreted so that it's the information one side has about the other side. Here he argues differently then I would, and uses a constraint of consistency. In my view this consistency is emergent, and corresponds to a kind of equilibrium.

This is close to view: There are not multiple universes, there are multiple observers :) And furthermore the constantly interact and evolve, and long with them does inferred physical law evolve.

He also argue for the evolving observers, which is really a resolution to the problem of defining the observer. Because no way how you define it you are lead to infinite regress. And unlike Dmitry67 who thinks that this is bad, I think it's good. Because this "infinite regress" is nothing but the evolving and dynamical world we witness.

If you stumble over that book, go right to the last section of "Einsteins Revenge" and see if you find that more convincing. There are also some conceptual arguments what observers always evolve, and that this is intermingled with the process of information updates.

Unlike what standard QM seems to suggest, information prcessing is not just about communication channels. There is also a sink and a source. The nodes, that store and hold information.

Here are I fully with one of Smolins example in that section, that and an observer IS his own memory device. And when an observer makes an observation, he unavoidably changes. The obvious part is that his state of information changes, but I'd add that also his memory hardware itself evolves.

He alse makes some additional arguments why it makes no sense to consider the wavefunction of the universe. It's beacuse it implictly assumes an observer sitting outside of the universe. So it's a non-physical position - it's an answer to a question none asks :) Unless you think God asks questions and that he needs our help ;)

FWIW, it's probably not going to convince you either, but if you get around to it check section 5 of https://www.amazon.com/dp/0195126645/?tag=pfamazon01-20. From how I see it, he doesn't say anything I haven't tried to say, but perhaps he is more convincing.

Also, the one think about Smolins reasoning I think is not so satisfactory is the actual CNS hypothesis of black hole spawning universes. I think his general motivation is justifiable and a lot of his overall reasoning is good, but there might be other ways to technically implement evolving law, than via black holes only.

But Smolin is one of the few physicists I've seen elaborate on this. Even though his general reasoning is hardly new, it's public attempt to application to physics seems so. so even if I don't share his ideas all the way, the general attitude is one of the best I've seen.

Some of the critic on Smolins reasoning here has not really made an impression on me either. Most attacks IMO misses that largest points he tries to convey. and I think the best way to understand it, is to see this also in the context of the scientific method. He is not just talking about "a theory", it is about seeing theory in context of a scientific process. Something that I think several critics seem to not appreciate.

/Fredrik

 

[Dmitry67]

Yes, I can. I have to modify the theory of gravity for this, but I have done this already before becoming a Bohm supporter. See ilja-schmelzer.de/glet.

Ha ha!
This is possible because you don't believe in black holes.
But wait, there are much MORE differences between GLET and GR then 4 items in your list.

jets from AGNs, possibility/impossibility of the reception of the gravitational waves, hypernovas, et cetera et cetera... Such radical theory has much more then 4 predictions different from SR. What is a reason for not giving your theory a chance to win? Put 20-30-100 predictions, the more predictions, the sooner your theory would win LOL

 

[Count Iblis]

What do the people opposed to MWI make of the thought experiment by David Deutsch in which you do a measurement and then forget the result of the measurement but not that the measurement was carried out, in such a way that the original wavefunction of the object is restored?

 

[DrChinese]

1. Feynman diagrams have nothing to do with paths or branches. To understand this, I suggest you to see a mathematical derivation of Feynman diagrams from first principles. For pedagogical purposes, I suggest you to see this within CLASSICAL (not quantum) mechanics (Refs. 52, 53).

2. It seems to me that you are not close at all.

Let me use an analogy. Consider a classical wave, say a wave on the surface of watter. It may have a complicated shape. Mathematically, it can be written as a Fourier sum of plane waves. But does it mean that plane waves are really there, that they are real? Not at all. Alternatively, it can also be written as a Taylor sum. But does it mean that particular terms in the Taylor expansion represent real objects? Again, not at all. All that makes a physical sense is the TOTAL function that describes the real wave. Particular terms in this or that expansion are nothing but a mathematical trick that simplifies calculations.

If it is still not clear to you, let me use an even simpler analogy. Assume that you have 1 apple. You can write it as
1=2+(-1)
Does it mean that you actually have 2 apples and -1 apple? Of course not. All you really have is 1 apple, and that's it.

1. I picked up ref 53 and am looking at that, thanks.

2. That is more or less what I thought I was saying... ...as reflecting your viewpoint. Elsewhere, you also said - which I think puts it nicely:

"The vacuum is an eigenstate of the operator of the number of particles, so there are no particle fluctuations in the vacuum. What fluctuates in the vacuum is the field, not particles."

The part about the field fluctuations was actually part of my original question: we have (what I called powerful) a fluctuating field. Depending on your interpretation, that field may represent the effect of "virtual particles" or may merely a mathematical device which leads us to better solutions.

But to consider your apple example: We see a series like: Results= .8(apple) + .001(apple+pear-2 grapes) + .04(apple+grape-grape) + .01(apple+pear-pear+orange-orange)... and somehow end up with a good answer. Obviously, the success of the path integral approach was that these expansions made mathematical sense. But they once again led to confusion about the underlying meaning. So I believe you are urging us not to consider that as evidence that there are oranges, grapes and pears jumping in and out of existence, and consider that we always* start with 1 apple and end up with 1 apple. It seems to me that those "extra" terms must map to "something non-local" in BM if it is going to explain the terms in the expansion.

(* Of course with higher energy or less stable particles, we don't always end up with the same coming out as in because there are decay modes. Which was one reason I was also asking about weak interactions.)

 

[dx]

What do the people opposed to MWI make of the thought experiment by David Deutsch in which you do a measurement and then forget the result of the measurement but not that the measurement was carried out, in such a way that the original wavefunction of the object is restored?

Could you give a more detailed description? I'm not familiar with the argument. I don't see how us forgetting things can have any effect on the wavefunction.

 

[Doc Al]

I have a cosmological question to the BM supporters.

What is price per barrel next year?
I mean, it is definitely pre-coded at the time of the Big bang, right :) ? Laplace determinism is valid for any deterministic single=history theory...

Why would determinism not apply even more so to MWI? Of course, it doesn't answer what happens in this world, but that's a fundamental issue with MWI, isn't it?

 

[Demystifier]

But to consider your apple example: We see a series like: Results= .8(apple) + .001(apple+pear-2 grapes) + .04(apple+grape-grape) + .01(apple+pear-pear+orange-orange)... and somehow end up with a good answer. Obviously, the success of the path integral approach was that these expansions made mathematical sense. But they once again led to confusion about the underlying meaning. So I believe you are urging us not to consider that as evidence that there are oranges, grapes and pears jumping in and out of existence, and consider that we always* start with 1 apple and end up with 1 apple. It seems to me that those "extra" terms must map to "something non-local" in BM if it is going to explain the terms in the expansion.

Like Feynman diagrams, path integrals are also nothing but a mathematical trick. Path integrals are nothing but a method of calculating the Green function. As you might know, Green functions are a useful mathematical device in solving ANY linear differential equations, including those that appear in classical physics. Thus, you can use the path integral method to solve the CLASSICAL harmonic oscillator or a CLASSICAL wave equation describing water waves.

What is relevant is the wave function. Even for BM this is all what is needed from standard QM. The way you have calculated the wave function (Feynman diagrams, path integrals, theory of special functions, Runge-Kuta method of numerical integration, ...) is completely irrelevant; there is no physics in it.

 

[Dmitry67]

Why would determinism not apply even more so to MWI? Of course, it doesn't answer what happens in this world, but that's a fundamental issue with MWI, isn't it?

Because it is not single history. In MWI has a unique symmetrical symmetry-breaking mechanism. I find it very beautiful.

So, look around. There is Sun, Earth and a void around. It is a symmetry breaking. Matter condensed HERE but not THERE. Why?

In deterministic theory you can not begin from a space with the same density and end with stars and galaxies! because if deterministic theory if 2 regions in space are in the same conditions then their evolution MUST be identical. If ALL regions are in the same state then ALL regions will continue to be in the same state.

In deterministic universe with simple initial conditions no there is no graitational instability: everyhting is in ABSOLUTE equlibrum - forever.

Deterministic theory can not, in princliple, break any symmetry, unless it is pre-coded in the initial conditions.

Now about MWI. Let's say we have 2 regions A and B, with the same density 0.5. So evolution is deterministic, so if we have sometimes after A=0.4, B=0.6 in one branch then we MUST have an opposite A=0.6, B=0.4 in another one.

Do you see how beautiful is it? Symmery is broken in every branch, but the whole universe remains symmetric and deterministic!

 

[Demystifier]

What do the people opposed to MWI make of the thought experiment by David Deutsch in which you do a measurement and then forget the result of the measurement but not that the measurement was carried out, in such a way that the original wavefunction of the object is restored?

From the Bohmian point of view, MWI is in fact correct (in the sense that the wave function does not collapse, making it consistent with the thought experiment above), but is not complete.

 

[Count Iblis]

Could you give a more detailed description? I'm not familiar with the argument.

The argument appeals to artificial intelligence that can be implemented by a quantum computer. So, the first part of the argument is that however the brain works, it is ultimtely formally describable using a finite number of bits. Therefore it can be implemented by a computer and thus also by a quantum computer.

The different branches of the observer correspond to the different projections of the quantum computer in the |0>, |1> basis of the qubits. Suppose that this observer measures the state of a qubit in the |0>, |1> basis. Let's call this qubit a "spin" to avoid confusion with the qubits that are part of the observer.

Then what we can achieve is the following.

1) We start with the spin in state |0>, then we rotate it to
1/sqrt(2) [|0> + |1>]


2) The observer then does a measurement in the |0>, |1> basis, which causes a qubit (that was initiallized to |0>) of his memory to be entangled with the state of the spin. This is performed using the controlled NOT gate. Also another qubit of his memory that was initialized to |0> is flipped to |1>. That qubit detects that a measurement has taken place (but not the result of the measurement).


3) The observer then applies the controlled NOT gate again, reversing the measurement. Then he flips another qubit that was initialized to |0> to |1>, which records the fact that the memory qubit that registered the spin has been erased.


4) At this stage the spin is back in the state 1/sqrt(2) [|0> + |1>]. The observer can verify this by applying the inverse rotation that he appied to the spin at the start, rotating it back to the state |0>. A measurement of the spin by the observer (or some other observer) will yield zero with 100% probability.


Now, the fact that the observer knows that he measured the spin in the |0>, |1> basis when it was rotated to 1/sqrt(2) [|0> + |1>] means that in the CI interpretation, the spin's state should have collapsed to either |0> or |1>. Only one of the branches really exists. Then, applying the inverse rotation won't bring the spin back to the state |0>, instead it will be a mixed state of

1/sqrt(2) [|0> + |1>]

and

1/sqrt(2) [|0> - |1>]

Measuring the spin again in the |0>, |1> basis must thus yield a 50% probability of finding it to be |0>.

 

[Fra]

Could you give a more detailed description? I'm not familiar with the argument. I don't see how us forgetting things can have any effect on the wavefunction.

I'm also interesting in hearing the detailed argument and the supposed problem. Since I'm not into MWI or Deutch I never read anything from him.

Edit: I just noticed that we got a response while I was typing. thanks.

About forgetting information in general though, in my view, this happens all the time for an evolving observer in the form of dissipation of actual history. If all history was retained, the mass of the observer would have to increase. This can happen, as well as that it can loose mass, but for a constant mass observer the evolving observer constantly processes information, remodels it's retains history and dissipates excess. I picture this as a form of radiation that is random (contains no informatin) _from the point of view of the observer_ but which generally does contain information relative to the environment.

/Fredrik

 

[DrChinese]

What is relevant is the wave function. Even for BM this is all what is needed from standard QM. The way you have calculated the wave function (Feynman diagrams, path integrals, theory of special functions, Runge-Kuta method of numerical integration, ...) is completely irrelevant; there is no physics in it.

I wouldn't say there is no physics in it. Excerpted from Wikipedia:

* The Casimir effect, where the ground state of the quantized electromagnetic field causes attraction between a pair of electrically neutral metal plates.

* The van der Waals force, which is partly due to the Casimir effect between two atoms.

* The so-called near field of radio antennas, where the magnetic effects of the current in the antenna wire and the charge effects of the wire's capacitive charge are detectable, but both of which effects disappear with increasing distance from the antenna much more quickly than do the influence of conventional electromagnetic waves, for which E is always equal to cB, and which are composed of real photons.

* The spontaneous emission of a photon during the decay of an excited atom or excited nucleus; such a decay is prohibited by ordinary quantum mechanics and requires the quantization of the electromagnetic field for its explanation.

* Lamb shift of positions of atomic levels.

* The Coulomb force between electric charges. It is caused by exchange of virtual photons. In symmetric 3-dimensional space this exchange results in inverse square law for force.

* The strong nuclear force between quarks - it is the result of interaction of virtual gluons. The residual of this force outside of quark triplets (neutron and proton) holds neutrons and protons together in nuclei, and is due to virtual mesons such as the pi meson and rho meson.

I realize you are saying that these effects are essentially an artifact of the math, but you have to admit that they are not the first things you would guess would come from something that is just a mathematical device. I mean, the virtual particle analogy seems pretty apt given the above. I admit that doesn't prove anything, just pointing out that the popularity of the viewpoint that virtual particles exist might be tied to the phenomena they help to explain.

And always, these "mathematically virtual particles" appear randomly without apparent cause. So that seems to go against the tenor of BM-type theories. If the psi^2 quantum equilibrium hypothesis for initial positions leads to the uncertainty in BM, which would otherwise be determinate, then I would expect another hypothesis to appear to explain additional random behavior of the field.

I don't think it all flows from that single hypothesis; but I could easily be wrong as I am not sufficiently versed in the matter. But maybe you can help on that. Or maybe that is what you have already said and I am too dense to follow. :)

 

[Demystifier]

And always, these "mathematically virtual particles" appear randomly without apparent cause.

This statement does not make any sense to me. Can you write down any equation that determines PROBABILITIES for the random appearance of these objects? I don't think so. Without a probability, it does not make sense to talk about their randomness.

Some physicists like to talk about virtual particles as if they really existed because they want to have some intuition about quantum processes, and yet do not want to cope with interpretations of QM seriously. But in my opinion, this is the worst thing to do. One should either strictly stick to the "shut up and calculate" approach, or think in terms of some of the logically consistent interpretations, such as Copenhagen, Bohm, many world, etc. Virtual particles do not play any serious role in any of these logically consistent interpretations.

 

[Dmitry67]

Demystifier, again, it depends on how you define what is a reality.
Tell me, is a real (non virtual) photon real?
You say, it is real? But do you know that photon is just a mixture of Z0 and anti-Z0?
So what is real, photon, Zo or anti-ZO? :)

 

[WaveJumper]

What about this research in New Scientist, where theorists claim most of the mass of real particles comes from virtual particles? Is this accepted as a valid description of reality?

http://www.newscientist.com/article/dn16095-its-confirmed-matter-is-merely-vacuum-fluctuations.html

 

[jtbell]

But do you know that photon is just a mixture of Z0 and anti-Z0?

Reference, please? I wasn't aware that there is such a thing as an anti-Z0.

A Google search quickly turned up a few pages from http://books.google.com/books?id=7toILlSQtI0C&pg=PA120&lpg=PA120&dq=z0+antiparticle&source=bl&ots=Lyksel-f45&sig=oiWWk2IJgEIGzvcjhp-zIgiFSZg&hl=en&ei=g7_dScWDBIXsyQWo_szRDg&sa=X&oi=book_result&ct=result&resnum=10#PPA121,M1 which includes the statement that "The Z0, photon and Higgs particle are each their own antiparticle..."

 

[Fra]

Nore sure I got the point here.

The argument appeals to artificial intelligence that can be implemented by...

Since I didn't ever think of this before, and the way I think of information in physics is different than the usual backgroun dependent information theory, I am not sure if I got the picture in clear here.

It's mentioned about "we rotate" and "the observer". How many views are in this picture? Does "we" refer to the observer, or to and external observer? From my perspecive, that is extremely important. If we have a memory device for example, who is describing it?

It seems the general idea is that

1. We have an observer, that prior to an interaction, has a certain expectation of the result of the measurement.
2. Then interaction takes place.
3. The observers expectation is updated.

so far so good

4. Now there is some construction where the observer looses the previous measurement result, but instead keeping some information about that a measurment has been made, as an attempt to "undo the information update"?

This physical basis of this construction is unclear to me.

The only way would then be to picture another interaction, whose resulting information update, would exactly cancel the previous update.

Is that possible in my view? Yes possibly. But an observer, can not CHOOSE what feedback to get. An observer can only choose what questions to ask, moreover it does not KNOW what the right question is, if he wants a particular answer. That's IMHO the whole basis for reasoning upon incomplete information, and an evolving observer.

The problem suggest is: what question should an observer ask, in order to provoce from the environment, a particular feedback (necessary to arrive at a certain state of information).

But this question can not be answered with certainty by the observer. If such an constraint is nervertheless imposed, then you are adding information to this picture, that the observer doesn't have.

So when this example, assumes that this right question is asked, and the tries to suggest that it implies an inconsistency, then the problem is that the inconsistency is arrived at by mixing information that belongs to different views. It's an abuse.

It's a mix of reasoning, a bird reasoning about how a frog behaves, suggesting that the frogs behaviour is inconsistent with the birds view. But this doesn't contradict a rational inside view. This is one of the effects of acting upon incomplete information, and as I see it the reason for existence of interactions.

In short, an inconsistency that is inferred from mixing two different views, is not a real contradicton. It's just an apparent paradox due to abuse. Ie. it's not an _observed inconsistency_ because the inconsistency can not be inferred by an inside observer. It's an inconsistency only in a thought experiment.

That somehow different views, seems to come to different conclusions, is not itself an inconsistency, instead it's in my view the basis for an interaction between the views. If two frogs disagree, it means there is an interacting between the frogs (they will "fight" each other"), which in turns leads to that frogs deforming. This is the prediction.

The inconsistency is more obvious though, if you relate it to a birds view, because it doesn't make sense if there are several birds views. So as I see it, the inconsisntecy is the idea that there exists a bird view. without this, I see no observable inconsistency. All there is are evolving frog views. What frog is "bird enough" to judge the global consistency here? IMO, none.

It is what I envision a relational ideal of interactions. The only way to compare view is by means of physical interaction, and clearly there are physical forces involved here. these forces, by magnitude and classification are related to the type and order of disagreement.

Note sure if this answered the question, but as far as I understood the thought experiment,
it seems doubtfully constructed. If so, the above is my response.

Other than that, perhaps there is a more clear description of the experiment explaning that is the observer and what is the computer and why/how these reversed measurements happens and from whose point of view.

I apologise if I missed the point.

/Fredrik

 

[Dmitry67]

photon and Z0 are mixtures of 'real' Zo and anti-Zo in the same sense as
KL and KS are mixtures of K0 and anti-K0
For that very reason both photon and 'apparent' Z0 are their own antiparticles.
I need more time to find a link. Not sure where it was...

 

[JustinLevy]

There are ways to turn discussions of foundational issues into experimental tests (such as Bell's inequalities). Speaking of which, I thought that some papers by the nobel laureate Tony Leggett combined with experiments, ruled out nonlocal-realism as well. A quick google search brought up a reference to this paper which may be the one I was remembering:
http://www.nature.com/nature/journal/v446/n7138/abs/nature05677.html

Some physicists like to talk about virtual particles as if they really existed because they want to have some intuition about quantum processes...

It is more than that. You are dismissing way too much here.

Note that the Dirac equation (the relativistic equivalent of Schrodinger's equation for spin 1/2 particles) can be solved exactly for the hydrogen atom. Despite this exact solution of the Dirac equation, this does NOT account for the Lamb shift. That is because solving the Dirac equation to obtain a wavefunction in that manner is forcing the assumption that particle number is constant (just like in non-relativistic quantum mechanics). It takes quantum field theory, which considers contributions from "fluctuations of particle number" to get the Lamb shift.

You essentially are arguing that we should only consider on-shell contributions. It is _very_ clear from experiment that we need to consider off-shell contributions.

Furthermore, to claim a particle is "real" or not only has a good mathematical definition in the limit the particle goes off to infinity. Only on-shell excitations can survive at that point, so one could argue that what makes a particle "real" or not is whether it is on-shell or not. However it is clear that such a black-white distinction cannot be made. As Griffith's elementary particles textbook likes to comment, would you consider a photon released from the sun and absorbed by your eye as "real"? The system of your eye and the sun would, in calculations treating them as one system, have that photon as an internal propagator in a feynman diagram. Similarly, the photon didn't exist forever, so will have a small off-shell component. (I'll even add, consider the top quark ... a distribution of masses is measured due to its short lifetime causing one to essentially just have a concept of "near-shell".) So there is no black-white distinction between "real" and "virtual" particles. You need them all.


The point is this: if you agree that fields exist and have quantized excitations, and you call these excitations particles, then you can't accept some and dismiss others as "not real" just because you don't like that physicists use the word "virtual" at times. Off-shell contributions are important, with experimental implications that have been verified. So people insisting on non-local realism would have to explain not just a particle deterministically, but also all off-shell fluctuations deterministically (even though there is not a "single" determined fluctuation, but the sum and interference of possible fluctuations).

You may be able to hobble together a theory equivalent to quantum mechanics in that it predicts the same values for all experiments, but to do so you would have to abandon much of what we learned about the deepest symmetries of physics. To cling onto one a priori expectation you have, you'd end up replacing real physics with adhoc results. Sure, Lorentz Ether Theory predicts the same results as Special Relativy for electrodynamics .. but do all those ad-hoc statements really amount to a better, or even useful, theory ... can you even call it an "interpretation" of a theory if you replace all the beauty and guts with something else to fit your a priori expectation? There is a reason LET and the Bohm interpretation haven't led to new predictions and advancement of physics. In my opinion they are a waste of time.

 

[Demystifier]

Tell me, is a real (non virtual) photon real?
You say, it is real? But do you know that photon is just a mixture of Z0 and anti-Z0?
So what is real, photon, Zo or anti-ZO? :)

First, you misunderstood something about electro-weak unification; photon is NOT a mixture of Z0 and anti-Z0.
Second, both MWI and BI agree that the photon wave function (which turns out to be a superposition of certain U(1) and SU(2) gauge wave functions) is real.

 

[Demystifier]

Speaking of which, I thought that some papers by the nobel laureate Tony Leggett combined with experiments, ruled out nonlocal-realism as well. A quick google search brought up a reference to this paper which may be the one I was remembering:
http://www.nature.com/nature/journal/v446/n7138/abs/nature05677.html

No, it just rules out SOME NAIVE VERSIONS of nonlocal realism.

Concerning virtual particles, I am not saying that you do not need to take into account their mathematical contribution to measurable quantities. Of course you do. But I am saying that you can obtain the same result on measurable quantities by applying a different calculation method (a non-perturbative method) in which the concept of a virtual particle does not even make sense.

 

[Dmitry67]

First, you misunderstood something about electro-weak unification; photon is NOT a mixture of Z0 and anti-Z0.
Second, both MWI and BI agree that the photon wave function (which turns out to be a superposition of certain U(1) and SU(2) gauge wave functions) is real.

Hm, it was on a papar source. I need more time.
Meanwhile, can I reformulate my question:

1 What particles from the list: K0, anti-K0, KL, KS are real?
2 Are quarks real? The fit the same criteria: like virtual particles, then can be just a mathematical model of barions.

 

[Demystifier]

1 What particles from the list: K0, anti-K0, KL, KS are real?
2 Are quarks real? The fit the same criteria: like virtual particles, then can be just a mathematical model of barions.

1. Any of them may be real, depending on the wave function.
2. If QCD is correct, then quarks in barions are real. If QCD is correct, then virtual particles are not real.

I have already explained the following, but let me try again. Virtual particles are NOT a part of a mathematical model (like QCD). Instead, virtual particles are a part of a specific mathematical method of calculation within the model (like perturbative QCD within QCD).

 

[Dmitry67]

1. Any of them may be real, depending on the wave function.
2. Virtual particles are NOT a part of a mathematical model (like QCD). Instead, virtual particles are a part of a specific mathematical method of calculation within the model (like perturbative QCD within QCD).

1. Well, check this link:
http://en.wikipedia.org/wiki/Kaon
Table, Quark contents for K-short and K-long.
Any comments?

2. The only way to tell these 2 things apart and prove that you're right is to suggest another mathematical method, which is virtual-particle free but gives the same result

 

[Demystifier]

So people insisting on non-local realism would have to explain not just a particle deterministically, but also all off-shell fluctuations deterministically (even though there is not a "single" determined fluctuation, but the sum and interference of possible fluctuations).

There is no such thing as a sum of fluctuations. There is only a sum of quantum states, represented e.g. by wave functions. In non-local realistic theories such as the Bohmian interpretation such wave functions are real and evolve deterministically, so they automatically contain the stuff you call "deterministic off-shell fluctuations".

 

[Demystifier]

2. The only way to tell these 2 things apart and prove that you're right is to suggest another mathematical method, which is virtual-particle free but gives the same result

Check out lattice QCD.
Or even better, check out certain low dimensional field theories that can be solved analytically.
Or as the simplest example, check out Ryder textbook on QFT, Sec. 9.3, where it is shown that a real free massive particle can be represented in terms of an infinite number of massless virtual particles.

 

[Demystifier]

1. Well, check this link:
http://en.wikipedia.org/wiki/Kaon
Table, Quark contents for K-short and K-long.
Any comments?

I am not sure what your point is. Is your point that kaons are not real, but that only quarks are real? If that is your point, then I agree. In this sense, I apologize for saying before that kaons were real.

 

[Ilja]

Ha ha!
This is possible because you don't believe in black holes.
But wait, there are much MORE differences between GLET and GR then 4 items in your list.

jets from AGNs, possibility/impossibility of the reception of the gravitational waves, hypernovas, et cetera et cetera... Such radical theory has much more then 4 predictions different from SR. What is a reason for not giving your theory a chance to win? Put 20-30-100 predictions, the more predictions, the sooner your theory would win LOL

Sorry, but I see no other differences. The theory has a natural GR limit, so there is no et cetera et cetera.

 

[DrChinese]

There is no such thing as a sum of fluctuations. There is only a sum of quantum states, represented e.g. by wave functions. In non-local realistic theories such as the Bohmian interpretation such wave functions are real and evolve deterministically, so they automatically contain the stuff you call "deterministic off-shell fluctuations".

JustinLevy said better what I was getting at. I am trying to follow your thinking, and am not intentionally trying to be dense. I understand that you view the extra contributions as deterministic, and that those contributions are not descriptive of virtual particles actually existing.

Yet I can't help but believe that in a non-local theory, there is a contribution from non-local particles which is "causing" the behavior we refer to as random. So if an electron (or unbound neutron or whatever) emits a photon (or the related decay products for other particle transitions) and drops to an inner shell, that behavior is caused by something. I do not believe you are asserting that there is any INTERNAL difference in one particle that decays vs. another which has not yet decayed, but might in the future. So the cause must be an EXTERNAL one, and I must assume that is a "field fluctuation" (or whatever terminology you want to use) and that fluctuation - a result of non-local influences - is the CAUSE determining what happens and when it happens.

So a) there is a BI particle - which is described by the mathematical apparatus we all agree upon - but which does not uniquely determine the trajectory or decay of that particle (else we wouldn't be having this discussion); and b) there is a BI field - with non-local components which supply the missing determinism (which includes both the particle trajectory and the actual decay time/mode); then c) it seems to me that a theory of the particle plus the field would be MORE than what current QFT supplies. That would be a good thing. :)

Am I getting a little closer yet?

 

[Dmitry67]

Sorry, but I see no other differences. The theory has a natural GR limit, so there is no et cetera et cetera.

For example, as there is no collapse to BH your theory predicts no Hypernova http://en.wikipedia.org/wiki/Hypernova and hence no Gamma Ray Bursts http://en.wikipedia.org/wiki/Gamma_ray_burst

 

[Dmitry67]

I am not sure what your point is. Is your point that kaons are not real, but that only quarks are real? If that is your point, then I agree. In this sense, I apologize for saying before that kaons were real.

My point is that if quarks are real, then how Kaons can contain an irrational number of them?
In fact, as K0 and anti-KO are almost indistnguishable, then we always observe a mixture of both.

So if kaons are not real, then how can they carry energy and momentum?
I also ask you as BM supporter, how many 'real' particles are 'guided' by the kaon wave?
In general, do you deny the 'real' existence to all particle mixtures?
Finally, if kaons as you are not real, are they virtual? or are there 3 types of particles - real, virtual, and something in the middle?

 

[Dmitry67]

First, you misunderstood something about electro-weak unification; photon is NOT a mixture of Z0 and anti-Z0.

But it is a mixture
http://en.wikipedia.org/wiki/Standard_model_(basic_details)#The_W.2C_Z_and_photon

Z bosons (Zμ) and photons (Aμ) are mixtures of W3 and B. The precise mixture is determined by the Weinberg angle.

The Weinberg angle or weak mixing angle is a parameter in the Weinberg-Salam theory of the electroweak force. It gives a relationship between the masses of the W and Z bosons (denoted as MW and MZ), as well as the ratio of Z boson mediated interaction which behaves like a photon, i.e. its mixing

 

[Demystifier]

But it is a mixture
http://en.wikipedia.org/wiki/Standard_model_(basic_details)#The_W.2C_Z_and_photon

More precisely, it is a superposition. And this is what I already said. MWI and BI agree on the ontological status of superpositions.

 

[Demystifier]

My point is that if quarks are real, then how Kaons can contain an irrational number of them?
In fact, as K0 and anti-KO are almost indistnguishable, then we always observe a mixture of both.

So if kaons are not real, then how can they carry energy and momentum?
I also ask you as BM supporter, how many 'real' particles are 'guided' by the kaon wave?
In general, do you deny the 'real' existence to all particle mixtures?
Finally, if kaons as you are not real, are they virtual? or are there 3 types of particles - real, virtual, and something in the middle?

Man, what are you talking about? All that "mixtures" you refer to are nothing but quantum superpositions. They have nothing to do with virtual particles.

Kaons are real (not real) in the same sense as classical tables and chairs are real (not real). They are real in the sense that they consist of fundamental entities which are real, but they are not real in the sense that it is a matter of human interpretation what will be considered as a chair, table, or kaon.

In addition, it seems to me that you don't understand well the difference between the concepts of quantum field operator and quantum state in quantum field theory. Someone who supports MWI, as you do, should understand that difference very well, because only the later has an ontological status in MWI. A state in QFT is NOT a superposition of "real" and "virtual" states; a state in QFT is a superposition of real states only. Thus, even your MWI says that virtual particles do not exist.

 

[Demystifier]

I also ask you as BM supporter, how many 'real' particles are 'guided' by the kaon wave?

Probably two. Although, perhaps this number could be even bigger, it is difficult to say with certainty with our incomplete understanding of nonperturbative QCD. For example, it could even turn out that kaon contains also something like a coherent state of gluons, which in the Bohmian interpretation would imply that kaon consists of an infinite number of pointlike particles. But all that is mainly a matter of nonperturbative QCD, while the Bohmian interpretation plays only a secondary role.

 

[Demystifier]

So the cause must be an EXTERNAL one, and I must assume that is a "field fluctuation" (or whatever terminology you want to use) and that fluctuation - a result of non-local influences - is the CAUSE determining what happens and when it happens.

Am I getting a little closer yet?

Since my paper is close to finishing, I can tell you that the sentence above is not so far from the Bohmian picture. More will become clear soon, when I upload the paper on arXiv.
For now, let me only tell you two things:
1. In BM, everything is determined by the initial conditions, but the initial conditions themselves are essentially random.
2. To have nonlocality and relativity at the same time, the concept of an "initial" condition should be radically revised. A part of it can be in the past, while another part of it can be in the future. [See http://xxx.lanl.gov/abs/0811.1905 .] Consequently, the initial condition may appear as something that occurs randomly during the evolution of the universe.

 

[QMessiah]

1. In BM, everything is determined by the initial conditions, but the initial conditions themselves are essentially random.
2. To have nonlocality and relativity at the same time, the concept of an "initial" condition should be radically revised. A part of it can be in the past, while another part of it can be in the future.

So Bohmian Mechanics require:

1. TRUE indeterminism/randomness at the fundamental level?
2. 10 000x The speed of light which inreturns means: a block universe/eternalism?


This is less realist than positivism =\

 

[Dmitry67]

Man, what are you talking about? All that "mixtures" you refer to are nothing but quantum superpositions. They have nothing to do with virtual particles.

Let me explain my point

Why I started to talk about mixtures? Becuae particles can be added, substracted, multiplied, divided by sqrt(2) et cetera. They are more like mathematical notions, not like tiny colored billiard balls with labels 'e', 'gamma', 'u', 'd' printed on them, as bohmians imagine :)

So the claim that 'virtual particles is just a mathematical method' looks as minimum very artifical, because the same particle arithmetics is valid for the real particles too. This thread had shown that the line between 'real' and 'virtual' is very fuzzy and you started to change your mind after my questions

If you still don't agree with me, please
1. provide a rule to tell if particle is real or not. How can we tell something which just appear in a 'mathematical method' from a real thing.
2. So, is photon (non-virtual one) real or not? are its 'ingrediants' (bosons) real or not?

 

[Dmitry67]

So Bohmian Mechanics require:

1. TRUE indeterminism/randomness at the fundamental level?
2. 10 000x The speed of light which inreturns means: a block universe/eternalism?

This is less realist than positivism =\

Yes, Bohmian mechanics:

TOE equations: 1 page
Initial conditions: 100000000000000000000000000000000000000000000 pages :)

 

[Demystifier]

Becuae particles can be added, substracted, multiplied, divided by sqrt(2) et cetera.

No, they cannot. Instead, these are quantum states in the physical Hilbert space (wave functions) that can be added, substracted, etc ...

They are more like mathematical notions, not like tiny colored billiard balls with labels 'e', 'gamma', 'u', 'd' printed on them, as bohmians imagine :)

No, Bohmians do not imagine this. According to Bohmians, particles only have trajectories. All other properties are properties of the wave functions, not of particles. Particles do not have any labels printed on them.

So the claim that 'virtual particles is just a mathematical method' looks as minimum very artifical, because the same particle arithmetics is valid for the real particles too.

No it isn't. The superposition principle is valid for physical states only. Not for virtual particles.

1. provide a rule to tell if particle is real or not. How can we tell something which just appear in a 'mathematical method' from a real thing.
2. So, is photon (non-virtual one) real or not? are its 'ingrediants' (bosons) real or not?

1. The particle is real if its motion is guided by the wave function that represents a state in the physical Hilbert space. Is that precise enough?
2. From 1. it follows that the particle guided by the photon wave function (which is a superposition of other boson wave functions) is real. But strictly speaking, it does not make sense to say that this particle is "photon" or that this particle is "some other boson". All we can say is that it is a pointlike object moving in spacetime.

Is it clearer now?

 

[Demystifier]

Yes, Bohmian mechanics:

TOE equations: 1 page
Initial conditions: 100000000000000000000000000000000000000000000 pages :)

And how many initial conditions is needed to specify a wave function in the MWI? I will tell you: An infinite number of pages.

Can you tell me just one thing: Do you really want to understand BI better, or do you just want to provoke people who disagree with you? I will not answer any of your further questions until you answer this one.

 

[Dmitry67]

1
No it isn't. The superposition principle is valid for physical states only. Not for virtual particles.

2. The particle is real if its motion is guided by the wave function that represents a state in the physical Hilbert space. Is that precise enough?

1. So what happens when electrons exchange virtual photons in QFT?
Virtual photons are the mixtures of other bosons!
based on your claim, virtual particles can not be superposition, so we can not talk about virtual photons.

2. Your definition not only requires one to accept BM,
but even if we accept BM, it is based on the 'motion', which is, in BM, is unobservable

 

[Dmitry67]

And how many initial conditions is needed to specify a wave function in the MWI? I will tell you: An infinite number of pages.

Wow, this is basics of MWI
In MWI you can start from a very simple initial conditions (for example, an empty space - a sort of vacuum before the inflation in the big bang) and get our current world as a result!

This is also true in CI: in CI because of randomness, in MWI each branch appear to be random, but the whole superset is not.

 

[Demystifier]

First answer my question in #96!

 

[JustinLevy]

Concerning virtual particles, I am not saying that you do not need to take into account their mathematical contribution to measurable quantities. Of course you do. But I am saying that you can obtain the same result on measurable quantities by applying a different calculation method (a non-perturbative method) in which the concept of a virtual particle does not even make sense.

No. You are missing an important point about 'virtual particles' here.
As I tried to explain, there is no black and white distinction.

Is a photon ever a real particle to you?
They are from quantization of the electromagnetic field. But strictly speaking anything we refer to as a photon in experiment is from perturbation theory. You could claim no "photons" exist, they are all just 'artifacts' of perturbation theory and that the full theory only has the full fields.

Again, do you consider a photon emitted from the sun and absorbed by our eye are real or virtual? Let's make it simpler. A photon is emitted during de-excitation of an atom and is absorbed by another atom. Was this photon real or not?

As I tried to explain earlier, the only consistent way we currently have to define a particle as "real" is off at infinity. With finite times there is a full continuum, with some definitions being appropriate extensions given particular applications, but ultimately there is no black and white distinction between real and virtual particles.

Your proposed definition doesn't resolve any of these issues.

There is no such thing as a sum of fluctuations. There is only a sum of quantum states, represented e.g. by wave functions. In non-local realistic theories such as the Bohmian interpretation such wave functions are real and evolve deterministically, so they automatically contain the stuff you call "deterministic off-shell fluctuations".

No. As a realism theory, you are requiring the "fluctuation" to have a definite (although unknown) value. Saying it is a definite superposition of values is no different (it is just a change of basis). You will not get the correct answer.

Also, if you are saying the vacuum is "really" in a definite state containing off-shell values, then one could measure the component of vacuum in such states ... ie. one could measure the vacuum to be in a state that violates lorentz symmetry, etc. That is incorrect. It's not that the vacuum expectation (ie. averaging over many measurements) has lorentz symmetry, but that every measurement will not violate special relativity.

1. In BM, everything is determined by the initial conditions, but the initial conditions themselves are essentially random.

Again, here by random, because you want a realism theory, you have to mean unknown but definite value. This is different than truly random.

Consider spin of an electron.
If you measure the electron to be in the spin up state (S_z=+1/2), then subsequently measure S_y, half the time you will get (S_y=-1/2) and the other half you will get (S_y=+1/2). Quantum mechanics says this is truly random. It was NOT in a definite, but unknown state until you measured it.
You instead are claiming it is.

So for quantum mechanics it is random. But for your BM interpretation, your "essentially random" is really only unknown initial conditions. Multiple interactions will have correlations that would differ from true randomness. They are not equivalent.

2. To have nonlocality and relativity at the same time, the concept of an "initial" condition should be radically revised. A part of it can be in the past, while another part of it can be in the future.

I must be frank here. I feel this is teetering on Metaphysics/philosophy and not actually physics. This proposes much additional structure that doesn't even sound testible.

Let me make a historical analogy. Consider Lorentz and his aether theory. He found that it had an interesting symmetry that forbid detecting the ether. He found this before Einstein even published his paper in 1905. The troubling thing is that even after people came to understand relativity and the powerful understanding that came with it, Lorentz wouldn't give up on the ether. To him, this was just a mathematical trick: Rods really did shrink and clocks ran slow becaue their internal interactions were different when they were moving with respect to the aether.

The two theories both predicted the same results for experiment. So one could claim that we merely have two different / valid interpretations of the same physics. However in Lorentz theory, the Lorentz symmetry is just a mystical conspiracy of the math and several ad-hoc conjectures. In Special Relativity, the lorentz symmetry is fundamental and those same conjectures can be derived.

Which is physics? I hope most would agree here that the existence of an aether which cannot be experimentally verified, and which to cast equations in the term of interactions with, requires demoting seemingly fundamental symmetries to mere 'coincidences', and worse yet do not provide new predictions are at best metaphysics.

The lesson:
Good physics does not come from mangling theories to insist on a priori beliefs based on intuition.


Your theories do the same. You destroy locality, but in such a contrived manner that it cannot be measured. Lorentz symmetry is now emergent, yet probing deeper at any level will not give details on this 'emergence'. And now you are laying ground to allow anything to be explained away by saying it deals with "initial" conditions in the future. Things will become even more convoluted if you actually manage to derive the lamb shift and the magnetic moment of the electron (it would be hard to take your "new QFT" seriously without at least showing how such calculations could be done in principle and showing the correct results should follow ... for relativistic quantum mechanics gets the wrong result, it took field theory to get the rest, so such calculations really demonstrate that final step from non-relativistic quantum -> relativistic quantum -> quantum field theory).


Any such theories are not seem by the mainstream as attempts to resolve 'foundational issues of quantum mechanics', but hiding behind the excuse of foundational issues to try to wedge in antiquated a priori intuition back into a theory.

They serve as examples of not what additional interpretations are compatible, but what must be sacrificed in order to force particular unnecessary requirements into a theory. These sacrifices are too big. It prevents any possibility of making new predictions/advances, so the theories are dead ends. Just as Lorentz ether theory serves only as historical example, so too do these ideas. No new predictions have come from it.