martillo

A necessary but not sufficient condition, I agree...

I saw it, "Enough of crackpots...". May be I'm considered as crackpot so I must mention two geniuses: "Without speculation there is no good and original observation." Charles Darwin. "No great discovery was ever made without a bold conjecture." Isaac Newton.

No, mathematics is not the machinery that runs the universe. Is the "tool" to describe the laws but does not explain how they are implemented.

Right, but this does not prevent us to think in how the laws are applied over the particles to make the universe run. As you said in that post: Still sailing I think.

"The Feynman Lectures on Physics": https://www.feynmanlectures.caltech.edu/I_07.html (just with a google search) Thanks for the readings. Very helpful. +1 I stay with: "No one has since given any machinery." I think all those geniuses didn't have the opportunity to know about computers and virtual games...

For me the fundamental entity is force F and the emergent property is Energy E defined as: E = ∫Fdx. Yes they do. IMHO the "Wave Mechanics" part of QM is not real. The concept of the photon and its dynamics (E = hν, photoelectric effect, Compton effect, etc.) is real. The equation E = mc2 is real for the photons but considering photons with mass m such that λ = h/mc. It is that those formulas do work but the theories developed behind are wrong for me. They are valid but for different physical phenomena than the described by those theories or models. Unfortunately I can't explain it more, entering in the category of personal theories I know...

I knew the conversation could lead us to the subject of wave-particle duality and here my participation reaches the end I think. I'm currently working on a model of particles that explains their wave-like behavior so solving the wave-particle problem for the particles' approach but I know this enter in the category of personal theories and I perfectly know I cannot go on with this here (@swansont remarked it to me several times). The wave-like behavior is explained with the concept of trains of particles which leads to a structure for the particles, a new model of the elementary particles surge and so on. Impossible to describe all this shortly. Too many areas of Physics affected. I appreciate very much all the time given to me by all of you in the forum. It is very important in my work to be able to discuss some things here but for my pain I'm not able to continue the conversation. Thanks a lot anyway.

Right at the beginning in your link it is said: "The Ehrenfest theorem, named after Paul Ehrenfest, an Austrian theoretical physicist at Leiden University, relates the time derivative of the expectation values of the position and momentum operators x and p to the expectation value of the force �=−�′(�) on a massive particle moving in a scalar potential �(�),[1]" Then it deals with particles. It deals with waves' functions but associated to the position and momentum of the particles. The associated Schrodinger's wave equation for instance, is related to the probability for a particle to be at some position at some time, it does not represent a particle made by waves but a wave mathematically associated to a particle. It's all about particles at the end.

I'm trying to get to your point but it is being rather difficult for me. I think what you are really asking is which of them, forces or energy, actually determines the kind of the reality of the universe. I mean, Newtonian Physics seems to be force based -- everything made by the forces -- while Relativity Physics seems to be energy based -- everything made by energy. If this is not what you are asking please let me know to be able to answer you properly. If that is actually the case then I would stay with forces because is what let me choose between a particles-based universe against a waves-based universe. Waves cannot explain forces. Only interference with addition or subtraction of their intensities is possible between waves, a wave cannot exert a force to another wave. For instance how to explain attraction or repulsion between things made of waves, how to explain collisions and bounces between them? All of them well verified as present in the reality we are. The universe becomes then particles-based then and not waves-based. Forces is then the determinant thing of the reality of our universe.

Both, forces and energy are two things of the same reality. Why only one would be real and the other not? You are right. Actually that experiment hasn't been tested for considerable different velocities in the labs so I cannot reach a valid conclusion. Only if different results would be obtained the existence of a preferred frame would be deduced. As for now you are right there's nothing that can demonstrate the existence of that frame. @swansont is right in that what matters in that experiment is the velocity relative to the crystal target.

But the 'rest' wavelength of a particle at rest is always infinite. λ =h/mv.

But right for non-inertial frames. In the line of understanding Physics I'm asking which velocity it is currently considered as right to apply on the De Broglie Law λ =h/mv. I think the considered velocity in practice is that measured in physics' laboratories and so a "stationary" frame is considered but laboratories are on Earth, which rotates and move around the Sun, which at its time moves in a Galaxy, and so on. There's no preferred lab to give the standard to obtain the velocity. So I ask, which is the totally right velocity to be used in the formula? relative to what referential? Right, no problem. Both are real, forces and energy. Any law of physics is real although not visible including the forces laws and the energies laws. Only objects in the Universe are visible, not the laws that govern their behavior. Both are real, the objects always made by the elementary particles and the laws that govern them. It is just that the laws are not directly visible. You can see their effects, like the the leaves of a tree moving by the force and energy of the air, but the forces and the energies are not directly visible. Can we agree on this? You say it changes with the observer frame. I can think in different labs over Earth, the moon, in the space whatever looking at the same experiment like Davisson-Germer experiment somewhere. They all will measure different velocities and so obtain different results. Which would be the right one then? That's a complicated problem to solve I agree. I would need some experiment to make on the rocks involving some frame dependent physics law. The results would be frame dependent and so it would be possible to decide but I would need that frame dependent law to test. I'm saying to @swansont and @MigLthat the De Broglie Law could be one but we are discussing about it right now...

I think you misunderstood something. I said for me there's no problem for acceleration, force, and even Newton Law to be frame dependent. Is Relativity Theory that makes a problem with its first principle stating that the laws of physics are the same and can be stated in their simplest form in all inertial frames of reference. For me is a too strong constraint imposed on the Physics Laws. For me some laws are frame dependent as Newton Second Law is. Consider for instance De Broglie Law λ =h/mv which depends on the velocity v. The question is, related to which referential is this velocity considered? For me the answer is a classical absolute frame at rest in the Universe. The velocity v is an absolute velocity. It is said this formula is invariant under the relativistic Lorentz Transform, fine, but the question remains: which velocity is considered? Velocity in relation to what? Only an absolute velocity relative to a frame at rest in the Universe makes sense to me. There are some formulations that do not use forces, fine, but what's the problem to have a formulation that do use the concept of forces? Why to deny the very useful concept of force? I don't understand that.

You gave up but may be others don't. You don't need to prevent them going on.

I apologize for a mistake in my previous post: I should have written: Now Newton Law states: a = F/m and we get: a' = F/m - A I had to went out in a hurry and couldn't verify and edit this at the time.

At least it gives answers for our current level understanding of the Universe. It opens another level for similar questions, I agree. But you know, the Greeks started with atoms, after came protons, electrons and neutrons and then now quarks, leptons and bosons. Who knows if yet another deeper level appears. So may be to pass to another level could be needed to be done.

Now returning to @joigus and @MigLsubjects: I think the concept of fictitious forces complicates it all. To avoid it let us consider that between accelerated frames what exist is a transform o coordinates. If A is the acceleration of a frame in relation to a stationary frame then the transform of coordinates is given by: a' = a - A where a is the acceleration of an object in the stationary frame and a' is the resultant acceleration of the object in the accelerated frame. Now Newton Law states: a = F/m and we get: a' = F/m + a where F is the (real) force acting on the object. Please don't try now to multiply both sides by m and as the units will correspond to forces introduce the names of pseudo- forces in the equation. Please let us stay just with that equation as it is formulated. Then what happens is that the resultant acceleration and so its relative motion changes. Particularly in a free fall, the acceleration of the accelerated frame is equal to the acceleration of the object and so the resultant acceleration of the object in the accelerated frame is zero: If a = A then a' = 0 The acceleration of the object in the accelerated frame is zero. The motion of the object is null, no motion. Now what about the force? The force is also zero. There's no force perceived in the accelerated frame. Both acceleration and force are frame dependent in accelerated frames. The force F is real but is not perceived in the accelerated frame of the free fall. What about Newton Law? Is not preserved. Newton Law is not valid in accelerated frames. It is valid in the classic inertial (Galilean) frames only. All this is valid within Classical Physics and I don't have any problem with the concepts here. I know you will say that The Force Law must be the same in all referential frames following the main principle of Relativity but what if it could be questioned? I mean many new theories are being developed with their own principles so why can't a new theory be developed just liberating from this constraining principle? Would it be counterintuitive or what to assume that some laws would be frame dependent? It is said Physics does not need to follow the common sense so why not to allow a theory without that principle? I do not pretend to discuss any new theory here. I'm just saying that may be it is possible to find a new model or theory with this feature.

Thanks. I have just posted a comment about the first: https://www.scienceforums.net/topic/128993-hijack-from-jumping-out-of-the-black-hole-what-about-the-event-horizon-from-nowhere-to-everywhere/?do=findComment&comment=1233038

Not ridiculous for me. I can think in an entire Universe running in some kind of "Universal Supra-Computer" running all physics laws (even the force law) over a (huge I know) set of elementary particles. That "machine" as powerful as needed of course.

Yes, everything discarding the concept of force. Why so much rejection to the concept of force? What is so bad with the concept of force to go on denying it? I don't get it...

Seems not. That's why the non classical approach is through "virtual photons". At Wikipedia (https://en.wikipedia.org/wiki/Virtual_particle) you can find the following: "In quantum field theory, forces—such as the electromagnetic repulsion or attraction between two charges—can be thought of as due to the exchange of virtual photons between the charges. Virtual photons are the exchange particle for the electromagnetic interaction." You must take into account what @swansont said:

I'm considering what you mention in deep also reading on your provided link about fictitious forces and also taking a look on the link about the equivalence principle. I don't know if I could reach to a good conclusion explaining my point of view. At a first look the consideration of the called "pseudo-forces" leaved Einstein to formulate his GR and I have no pretension at all to challenge that but seems this is involved someway and that's why you are following the conversation, isn't it? I mean, my statement that forces are real is challenging GR in its proper beginnings. I wasn't actually aware about that and it will take time for me to be able to defend my position if it was the case I could. As I said I'm not sure I could be able to do it. I will return if I find something good to present only.

Yes I got confused about that again. I was editing my post now to not mention "inertial frame"... I consider a Galilean transformation as between frames moving at a constant velocity between themselves. Am I wrong in that?

I told you many times that in a free falling frame Galilean Physics does not apply as in the example. The frame is not moving at constant velocity, it is accelerating in relation to Earth. In the second case, where was the non-existent force? It's precisely because I'm taking you dead-seriously that I ask you these questions. Otherwise, I wouldn't entertain this conversation. I already said that to get the complete picture we must consider the relative movement between me and Earth. If you put a frame on me on my free falling I don't move in that frame and is Earth that moves accelerated to me. There's a force acting on Earth now.

No I don't. Actually I think you are just not taking me seriously... Same as for @joigus. You are just not taking me seriously... Actually I don't want to continue discussing this. You seem to not understand what I say.