Bob_for_short

It has always been clear. The energy is measurable. The energy is exchangeable. The energy is a certain property of a system. There are many forms of energy. Each is well defined. Why to fool ourselves?

Somebody pushed them apart in the past and they fly apart since then.

regarding equations of anharmonc oscillation while solving we 1st ignore the anharmonic term say ax square. then we put that solution in the equation and try to solve it again. i dont understand how it reduces the error? please explain.

We expand the exact solution in series in powers of a small parameter. We consider the anharmonic term as small. So the zeroth-order approximation satisfies the pure harmonic equation. We find it. Then we try to obtain an equation for the first correction. For that we put them together in the equation. We obtain an equation which contains now the known zeroth-order approximation in the anharmonic term. The zeroth-order solution plus the first-order correction is a more accurate solution (smaller error).

I made a double-slit experiment with only one photon. I obtained one point on my screen. I wanted to get the other points from the other worlds in order to superimpose them and obtain an interference picture. I looked at the screen, behind it, and also in all perpendicular and non perpendicular directions. I have not found any other screens, leaving alone other worlds, and thus no additional points.

Then I repeated my experiment with projecting many-many photons at the same time and immediately obtained a descent interference picture (ensemble of points). I managed to carry out the experiment in this sole world without problem. So I decided that MWI guys were cheating me for fun.

I have searched for gold many times where it should be and found nothing. Therefore, the only logical conclusion is that gold does not exist.

Correct. Somebody fooled me with other worlds and someone fooled you with gold mines (run out of gold obviously).

I have searched many times there where they should be and found nothing.

I was asking you to prove that the Many World Interpretation is wrong (since you made the claim that it is).

Let us suppose that MWI is right. Than we should have the other worlds at hands together with our world in order to make sure that other possibilities are well realized in them. But we don't have them. Then why to involve or invent something in our science that we do not have for sure?

Conclusion: MWI is wrong as it appeals to non existing other worlds.

The same is valid for lost and hidden variables.

...An interpretation is just a "retelling" of a calculation or mathematical construction using words...

Yes, whatever the words mean, as soon as you use words, it is already an interpretation, and nobody can blame you for that.

Prove what? That there are no other worlds? That people, insted of accepting the complexity of this world, invent deterministic pictures furnished with hidden parameters or other interpretations? The fact that there are many of them and they are different proves already what you ask.

While I agree with that (i.e. which QM interpretation you chose is not science, but opinion or belief), I don't think the many-worlds interpretation is any scientifically less reasonable than the Copenhagen interpretation.

I did not tell that the MWI is the only wrong one. There are many of them. Still, we all in our daily practice think of this world solely. This is sufficient, fortunately.

As soon as we (you) replace the word "vacuum" with the right term "the ground state of the system", no paradoxes will arise. You have a system in the minimal possible energetic state. Nothing to harness. As simple as that.

...And who are you to decide the Many Worlds Interpretation is a weakness of some physicists?

I am somebody who has his own opinion based on his own experience (practice).

Referring to other worlds without any possibility to verify where they are and what happens there is not science. It's telling stories.

Everybody in life cares about this world. This is the human practice. And science is a systematisation of facts of this practice.

The Swansont first paragraph is the most exact answer. Referring to parallel universes is a weakness of some physicists. Give sufficient number of trials and even a low-probable event will occur. As simple as that.

I need a salary from nothing. It's much less than the Universe.

Let us consider a long-wave radiation with a short antenna. Is the EM wave separated from antenna?

You see, any radiation needs a source somewhere. It does not appear in a fully empty space.

Let us consider a thermoelectric emission of electrons from radio-lamp cathods. It is a transfer from the ground to highly excited states of cathod atoms.

Any radiation - photons and pairs is a transition from the ground state (=quantum vacuum) to an excited state of the original, real system rather than of empty space (classical vacuum). Thus the "virtual particles" belong to real particles/systems and not to the empty space. It is a real particle feature. Without it there is no virtual particles.

The pairs are created from the quantum vacuum, not from empty space (=classical vacuum).

These particles do exist as said previously in the post. This is how black holes give off thermal radiation. Have you ever read any Hawking?

Yes, I did. I attract your attention to the fact that it is the blackhole that radiates, as any material system out of thermal equilibrium with its environment.

This is where ideas come from, where'd science be without ideas?

You had a good idea. It is not your problem that it failed but of those who are responsible for speaking of "vacuum energy" in empty space.

I am only against a vulgarization of science. Those questions about harnessing the "vacuum energy" are provoked by this vulgarization. And I give an explanation what is meant by the virtual particles.

These are experimental evidence of real particle interactions. Think of the Coulomb potential. In QED it is a "photon propagator" called also a "virtual photon". But in fact, it is mainly a usual Coulomb potential (solution of the field equation with a charge as a source). Some minor quantum corrections to it do not invalidate the physics - it is an inter-particle interaction of real particles.

It is quite incorrect to think that a usual empty space (classical vacuum) is filled with virtual particles.

I guess if ur constantly trying to keep imaginary particles in existence you would need to use energy to keep it going anyway, so better off just to use classical propulsion and gravity assists.

There is no imaginary or virtual particles, as a matter of fact. It's an awkward way of physicists to name interactions (forces like Coulomb one) in calculations.

Accelerators can provide high momentum particles which is an efficient way to create a recoil, but! But the particles are charged and to keep the space-ship neutral you have to eject the equal numbers of positive and negative particles. It is done indeed - in the so called ion-jet engines which in fact eject neutral plasma beams.

Would it be possible to somehow tap vacuum energy to create a force to propel a spacecraft? What would you need to harness it?

In an empty space (a classical vacuum) there is nothing.

A quantum vacuum is a synonym to the ground state of some compound system. If your spaceship is cold (T=0) it is in its ground state. Thus there is nothing to harness.

If your spaceship is hot (T>0) it can emit an electromagnetic radiation. It provides a kind of radiative recoil. It is rather inefficient though. Better "radiate" particles, as in jet engines. This is how the excess of energy (the energy above the ground state in the combustion chamber) is employed.

In fact, what is usually said about the Casimir effect is not virtual pairs (electron-positron pairs) but virtual photons or the "zero-point energy" of the virtual photons. Casimir first predicted this effect and later on they measured that force.

The strict understanding of this effect is a long-distance interaction of neutralized charges. It is their potential energy that is calculated and its gradient determines the force.

You know, it QM the charges are "smeared" quantum mechanically, they are not point-like, so their interaction is somewhat different from pure point-like particle interaction. In addition, there is the quantized electromagnetic field "hooked" at each charge that gives an additional smearing. For neutralized distant charges this additional force dominates.

It is quite similar to attraction (or interaction) of distant neutral atoms, a la van der Waals force. Gravity effect is too weak.

So we arrive to the conclusion that we cannot, despite a huge number of textbooks, give an answer to the question in the frame of virtual particles.

On the other hand, there is the Coulomb gauge where the Coulomb potential is clearly written. It leads to bound states an other obvious effects. That is why I have given my answer in terms of potential energy terms.

virtual photon <-> internal propagator <-> mathematical term [math]\sim \frac{1}{p^{2}}[/math] where [math]p[/math] is the momentum.

 

I have no idea how one could interpret any of this outside perturbation theory. Any ideas welcomed.

There is no need to go outside the perturbation theory. Just fulfil the calculation to the end or make transition to the configurational space. You will obtain 1/r + magnetic terms from your propagator. That's the force terms.