Can you be more specific about what aspect of superluminal effect you are talking about? Entanglement and collapse do not cause information to be superluminal transmitted. The collapse is only a result of an abstract and black box model of the observer and observation process, for the convenience of treatment. If the observer is treated within the model, then it comes as a simple decoherence process. Measurements don't really toss the coin, but rather, the measurements cause the observer to be entangled as well. My understanding is that, simply by putting the observer out of the system as a black box object, we prevented the observer from being able to be entangled, and for that to happen we have to collapse the wave function of the system. Since this whole collapse business is just an artifact of theoretical simplifications, I wouldn't indulge too much into the metaphysical implications of it.

Regardless of what you intend by "superluminal" (nonlocality?), the answer to your question of whether the probabilistic formalism (or better yet, statistical) is "natural" would be a very strong "no". Probability, as computed, used, applied, etc., across the sciences is the same everywhere EXCEPT in quantum physics (and extensions or versions of it). Nobody else uses the mod square of the amplitude to calculate probability, they use probability. Probability in QM is analogous to calculating the probability of your coin toss as being either heads or tails and something else (total probability isn't simply the sum of all mutually exclusive outcomes).

Yes, I agree with you. Measurement is not a 'wave function collapse' except in the subjective probability sense as you say.

I do not quite understand the question. In quantum mechanics, there is a strict mathematical operation that is equivalent to what you call "collapse." This is a projection of the mixed state (or wave packet) to a set of eigenfunctions of operator of the measured physical quantity. You can believe that the measurement process produces such a projection or collapse of the wave packet.

Yes!

@Johan

The question is: if the "collapse" is a physical process or a subjective sense? If it is a physical process, but how fast? The other question that should be clarified is: If the "probability" is a reality or is it just a limit thing such as infinity?

I disagree . Collapse includes always a semantic act and thus involves our mind entities. May I suggest to give a look at my publications and , in particular, to that one on International Journal of Theoretical physics where a proof od basic Von Neumann postulates on measurement is given?

Johan, you have answered after 47 minutes to my questions and also adding unpleasent comments."This is not physics.". It seems that God is arrived able to establish what it is physics and waht it is not. May I suggest that you first read the suggested papers and after elaborate your comments?

Dear Johan ... I have not accustomed to speak withy colleagues that pose conditions to read the papers of colleagues. For your information , in any case, I have papers that ALWAYS contain basic theoretical elaborations and EXPERIMENTAL CONFIRMATIONS . I have not arrived to 68 waiting for some colleague explaining me waht is physics. So may be that our discussion stops here.

I hope you will read ...physics.....and understand it !! It is necessary , I retain as of course for all! ....Please... stop here this so irritating discussion . I no more will answer you!

Johan

Where is your VooDoo coming from that in vacuum a light/photon wave-packet would have a speed different from c? there is no dispersion thus

d(omega)/dk=omega/k

phase = group velocity=c

Thank you all for the good answers above.

The group velocity can be larger than c because the "dispersion" of the wave packet gives a modification to the shape of the wave packet which can "push" the particle for a while (slow down the light pulse in a lattice or in atomic gases is the same thing).

Ok, all guys, cheers up! Let us refine our question as follows: If the quantum theory physically breaks the causality law? Or in the other words, if a detection now can influence a result before? Here the result (for quantum theory) is the value of the probability!

Johan

Your Voodoo: a wavepacket is NOT a solution of the wave-equation? SHOW me

Johan

domega/dk for light is a continuous function, namely 2pi*c, meaning an inverse relation between frequency and wave-lngth independent of the wavelngth; no dispersion

This simple CALCULUS beats yours

Sorry for chiming in late; could somebody explain me what exactly is meant by "wave packet collapse"?

As I understand how things stand in nonrelativistic quantum mechanics is that there are particles, size zero (I really won't advise to introduce finite size quantum systems-leads to non locality and this changes the whole game), interaction is local and probability of finding a particle electron (not wave, particle) is given by an amplitude squared and this amplitude is given by the solution of the wave equation which brings in this insubstantial :wave-particle duality". Electron (photon is bit different case, always moves with c, thus relativistic) is just a size zero particle, never wave, thus no any physical collapse happens...

"An electron is an EM wave" - now, that's new, where did it came from, which experiment points to it?

Anyway, since I do not know how to treat finite size systems (I suspect not anyone in this discussion), I stop here.

Not demanding answer, but, what, relativistic electron - which are in abundance - are very, very elongated objects?

Johan

I gave you the photon you reply with the electron. Ever learnt the relation omega*k=c*2pi

Johan

That is you in essence; never answer the original question and nagging about a pie

I asked you why (the hell: your standard wording) a wave-packet has a different phase and group velocity in vacuum?.

Dear Johan:

I am not sure that you always can tell us the truth because of your rich imagination! e.g.,

"@The faster it moves, the longer it is."

Actually, according to De Broglie formula, The faster the electron moves, the shorter the wavelength is, right?

"@I have a SINGLE electron differential wave equation with boundary conditions given by V(x,y,z), and solve it to get all the possible solutions psi(1), ps(2), psi(3); etc. Only one of them can be the electron-wave: If the electron-wave is given by psi(n) for example, ALL the other possible solutions DO NOT EXIST. "

"@Now please prove to me why you maintain that each one of these possible solutions must be a wave-packet. I say that not one of them can be a wave-packet. Each has a SINGLE definite frequency, and NOT a superposition of frequencies, as it must have to be a wave-packet."

If the electron-wave is given by a wave-packet which is the superposition state of psi(1), psi(2),...., how you can say that the other possible solutions do not exist? Do you mean the energy (frequency) of the electron is fixed and thus the wave-packet does not exist? But if the electron is not in an eigenstates but in a superposition state, the energy is not fixed, right?

Thanks

Johan

To answer in your prose: BS your photon

Modern photophysics prepares single photons with a measurable time duration and coherence length: a wavepacket. Tell me how in your physics the oxymoron "single-frequency" photon can be reconciled with those measured properties

Ans again: I ask the photon, you reply the electron; who is demented here?

Ever heard of the time dependent S-equation?

Johan

electrons are like photons? what happened to zero-point mass

photons can not only be a wave-packet because in absence of dispersion omega=kc holds indeed but for both the phase and group velocity. Single photons are pulse, other word for wave-packets. As for single frequency single-photon sources: you provide the example of such a source. This is not theoretical VooDoo but an applied question

That exactly shows your utter ignorance man: I asked you for an example and you give me abstract Voodoo about an "endless" photon. Therefore where is it in space: from here to eternity. For me emission of a single photon from one molecule at the bandwidth limited pulse-width is well described and can be used in practice. with your Voodoo I have to wait for ever to measure its frequency

A photon can be a vacuum wave with a single frequency in theory, but that has no practical meaning because its location is absolutely undefined; therefore it is by definition endless and no double-dutch even. A photon is defined as a wave-packet in real-life as in the single photon source I am familiar with

You continue to duck give me the example of a single frequency photon in real life not in Voodoo-land

"A single photon" is just a model, not real. One can not distinguish photon one by one in an e.m field. Johan want to give a classical interpretation of quantum world with deterministic events under a statistical framework. Is it quantum trajectory theory? If a photon has definite frequency, then the life time of the excited level will be infinite!

Your problem is that you do not understand real life photophysics. Yes the universal EM filed can be thought of being composed of dirac-type frwuency modes for the photon. Describe how a transition in an atom / molecule works emitting a singledirac- photon of one (?) frequency from the time-dependent S-equation or do you also here have your own Voodoo formulation?

By the way you get upset when approached in a satirical way ?! How you think anybody else feels under your continuing insults on honest replies?

Dear all, thank you so much for all your answers and comments.

OK, let us discuss like a gentleman, Johan! Do you mean a photon is a plane wave with a speed of c? But I always "see" e.m. pulse in the Lab and how to describe it then?

Dear Johan,

"What do you mean by posting that you do not know "how to treat finite size systems". Do you imply that you know how to treat "infinite size system"." - I know more or less OK how to work with/treat elementary systems, measure zero. AFAIK, niether math nor physics for a continuous finite size bodies are in existence yet,

Johan

Your mantra of single photon = single frequency does not provide me any insight in the single photon emission of single molecules whereas the in your eyes despicable Dirac and consorts at least gives the means to predict next steps and that is what a theory is meant for to give directions for new items. Physics is a practical sports and its ideas describe observables. A single frequency photon is an example of non-observ(able)ed

And to give you my mantra

group velocity = space velocity of a photon wave-packet in vacuum, without dispersion; or can't you differentiate a linear function?

where is the dispersion coming from in vacuum and how do you explain the finite width of a photon pulse from a single photon source and the Hanbury BT detection

And I have no interest in a harmonic

read the publication that I attached some entries ago

I am flattered that not all I post is nonsense to you when i read replies to anyone else

Reading the reference cited below, one finds that the wave packet collapse is needed when you associate the psi-function with just one system.

For example, with one electron.

On the contrary, if you accept that a psi-function gives us information about the state of an statistical ensemble, then you do not need the collapse.

So, it is a question of the the interpretation of the quantum mechanics.

See for example:

T. A. Brody, The philosophy behind physics, Springer-Verlag (1994)

Hi!

I didn't read the entire sequence, but am of the impression that the wave equation for a photon is not completely straight forward as described in the following two papers:

Solutions of the Maxwell equations and photon wave function, Peter J. Mohr, Annals of Physics 325, 607-663 (2010).

ON THE WAVE FUNCTION OF THE PHOTON, BIALYNICKI-BIRULA, Vol. 86 (1994) ACTA PIIYSICA POLONICA A No. 1-2

Zhang,

You are essentially right. If you regard the wavefunction as just probability information, then the collapse is nothing remarkable. I tis no different to classical physics where we get extra information [from a measurement] that changes the probability function everywhere instantly. What distinguishes quantum theory is that we cannot construct a local hidden variable theory. So the classical idea that there is an underlying reality and that we use probability functions when we don't know all the details, that can't be applied to quantum theory.

I hope that helps.

The ONLY thing that quantum theory does is give the probabilistic results of experiments. Anything else is conjecture or interpretation - and there are lots of those.

The first thing we should examined, is the sense that quantum physicist use of the concept of probability. Actually they use some kind of frequntistic probability. One should not forget that Quantum theory, is a non-classical theory, whereas "probability theory" it is rather classical (The law of excluded middle holds with probability one!).

Thus it is not a good practice to mix classical and not classical theories. Sooner or later we should encounter some kind of paradox!

Johan

@"Why must quantum waves be interpreted in terms of probabilities? You cannot show a single experiment which requires that this must be so for us to understand what is happening at the atomic scale"

Ever heard of (quantum) chemistry and the electron charge distribution in molecules?

Johan

1. What's Higgs got to do with formation of molecules?

2. Give me an alternative for Chem to explain the details of molecules

Johan

In my previous entry I meant "Quantum Chemistry" iso "Chem"

Please, explain me the following result that I have of course published.

Take a logical statement that we may express , as you know, in standard quantum theory as well as using a difefernt mathematics.. as example the Clifford Algebra.

How may we explain that by using some given linear transformations we may obtain by such logical statements the same formula that is usually obtained in quantum theory relating what we recall often as quantum interference?

I will not answer and I apologize with all you , I forgot that time ago I informed you to go out from such question and so forgetting to day I received other answers and I was induced to answer. Sorry, I aplogize once again. Please , consider that never I wrote my consideration of 3 hours ago.

Hello to all

I just started a thread about entanglement in

https://www.researchgate.net/post/Is_quantum_entanglement_any_better_than_classical_entanglement

There I give examples in ordinary three dimensional space and in four dimensional space-time to illustrate what is, in my view, the meaning of entanglement. No wave functions appear here. It is seen that a position in 3-space is the entanglement of three multiples of normalized coordinate vectors. Similarly if a time coordinate is added.

A possibly more general classical mechanics example is also hinted.

Finally, "quantum entanglement" of wave functions is defined and seen to be essentially another way to say "linear combination". Therefore quantum entanglement is not new, nor deep.

Of course any person is free to consider quantum entanglement as something mysterious or as a promise of fresh insights into the nature of microscopic physical phenomena. I wish them luck.

Most cordially and with best regards,

Daniel Crespin

To Johan Prins:

In answer to your questions:

Why must quantum waves be interpreted in terms of probabilities? You cannot show a single experiment which requires that this must be so for us to understand what is happening at the atomic scale.

Consider the following statement: Given a single particle in an excited state at time t=0, the probability that the particle will still be in the excited state at time t'>t is given by p = exp(-t'/tau), If you carry out this type of experiment N times, the measured times that the particles remain in the excited state will vary from t'>tau, but the average of all of the measured times will approach tau in the limit as N approaches infinity.

What part of this statement do you dispute or how do you reword it to avoid probabilities?

Johan

Alternative I ask for:

To start with: the Aufbau-principle; follows crystal clear from a multi-fermion particle/wave description.

Then Valency

Ok, Johan, you can say that the particle is a local wave! But I still think the protons, electrons or the atoms are particles because they can be separated to be individuals. The wave is not a local thing and continuous which is hard to be separated! Is it right?

Dear Lin:

I can only say that I've yet to come across a "Schrödinger kitten" larger than the one found in this study:

Gerlich, S., et al.. (2011). Quantum interference of large organic molecules. Nature communications, 2, 263.

but that doesn't mean there are not macroscopic "Schrödinger cats" that consist of multiple atoms yet are detected in superposition states and are larger than the 430 in the study above. It seems to me to be a little hard to argue that such matter should be considered to be particles when not only are they not localized, but to the extent they retain some ontological status as "separated to be individuals" they are observed to be so nonlocally. Particles in particle physics are still described by e.g., a de Broglie wavefunction and are never truly localized or individualized (any more than light can be). We now have experimental realization of Wheeler's delayed-choice experiment too. The retention of terminology from classical physics is simply misleading. Strictly speaking there is nothing in modern physics that is either waves or particles, but as everything is at best only approximately localized and "individualized" (and that the mathematical structure and apparati used to obtain the localized "particles" is only able to do so in any consistent fashion by treating them as nonlocalized "waves"), isn't it about time to relegate particles to the same realm of useful but flawed conceptualizations we have e.g., Newtonian gravity?

Johan

where the hell in your words do the classical fermions come from with only 2 per state-function.

What is your classical explanation of a wave-function and what explains the formation of a molecule from atoms? A classical S-equation? What is the formalism and how to work with it to describe the energy levels and thus interaction with the EM field. what we get from you is platitudes iso of a developed theory like Quantum Chemistry is

To Johan Prins,

Returning to your question, "Why must quantum waves be interpreted in terms of probabilities? You cannot show a single experiment which requires that this must be so for us to understand what is happening at the atomic scale."

My previous response can be stated without reference to particles:

Consider the following statement: Given a single Tritium nucleus at time t=0, the probability that the nucleus will still be a Tritium nucleus instead of a Helium 3 nucleus at time t>0 is given by p = exp(-t/T), where T = 4500 days plus/or minus a few days is the half-life of the tritium nucleus. If you carry out this type of experiment N times, the measured times that the particles remain in the excited state will vary from t>T, but the average of all of the measured times will approach T in the limit as N approaches infinity.

What part of this statement do you dispute or how do you reword it to avoid probabilities?

Johan,

It seems pretty reasonable to me to interpret the waves as probability waves because you can very accurately calculate the transition rate of a decay process by integrating over all space the complex conjugate of the final state wave function times the operator for the physical interaction that causes the transition times the wave function for the initial state.

Johan

With platitudes I mean that you only criticize but do not provide a formalism yourself

What is in your Lorentzian approach the description of the simplest chemical compound, a hydrogen molecule?

Johan,

Restricting my answer to your objection to the use of probability in discussions of electron- and photon-waves, specifically,

" I do not dispute your experiment: I only dispute the interpretation that this requires that electron-waves and photon-waves must be interpreted as probability waves."

and my reply,

"It seems pretty reasonable to me to interpret the waves as probability waves because you can very accurately calculate the transition rate of a decay process by integrating over all space the complex conjugate of the final state wave function times the operator for the physical interaction that causes the transition times the wave function for the initial state."

and your reply,

"The transition rate of any process in physics is determined by the average number of attempts a single entity, of an ensemble of identical entities, makes before succeeding in changing its state. This is real physics! It does not require that the entity itself must be a probability distribution of anything."

my reply is,

what you just described immediately above is properly treated mathematically as a memory-less processed governed by an underlying random probability distribution independent of any physical interpretation because it is not possible to compute the number of attempts before succeeding, nor which attempt will succeed, nor the time elapsed between any two successes. Instead, it is possible only to calculate the expectation value of the average value of the last two of these. Similar restrictions apply for events that can occur at different locations in space like the absorption of a photon by the pixels in a CCD array that is irradiated with a uniform, collimated beam of light.

Johan

Your reply is exactly what I mean with platitude. I ask you your formalism for the hydrogen molecule and of course you do not give that, but instead ask me my preferred (?) description of which you know the answer already

Johan,

I think that we have reached an impasse. If you believe that it is valid to apply the concept and tools of probability to an ensemble of atoms, but that it is not valid to apply these same concepts and tools to an individual atom, I don't know what to say next.

All I can do is quote the Wikipedia for a commonly accepted definition: "Probability is a measure of the likeliness that an event will occur" To me, the transition rate can be used to calculate the probability that one and only one atom will decay in any given time interval, and I can make money if anyone wants to bet a lot of times against the predictions based on the transition rate.

Johan

You initiated this by asking to give an example where the probability-description was of use; then, when you don't like the discussion you duck