Superconductivity at room temperature??

[D'rok]

I thus decided to rather look at superconduction in general and study myself into the subject; since my previous research was not directly in this field.

I suspect this is the root of the problem. It looks to me like you studied yourself into a misunderstanding of the subject. It isn't possible to overturn a discipline that you don't completely understand - i.e., I don't think you are equipped to distinguish between errors and radical new discoveries.

 

[johanfprins]

I just realized something really funny.

Here's Johan a few pages back. At the time, he thought that *of course* there would be charge on an iron-copper interface, that it obeyed Gauss's Law and cancelled part of the field.
At the time, he didn't mind believing this because he thought he knew why it wouldn't invalidate his superconductor theory. It's fine to partially cancel a field (as in iron-copper-iron) but since it would never add up to totally cancel the field, it didn't contradict his superconductor theories. (A confusing detail: at the time, we were talking about a hypothetical "zero-resistivity copper").

Yes as I have posted above, I have never encoutered this reasoning before, and it put me on a learning curve. I thus decided to give you the benefit of the doubt. Further contemplation, however, convinced me that it is impossible for charge-carriers to accumulate at any interface along a circuit for which Ohm's law is valid. Thus, I should not have given you the benefit of the doubt: I should have realised that, as usual, you are just wrong!

Of course, the total-cancellation argument fell apart---in fact, you can get whatever charge you need to get the currents to equilibrate, up to and including total cancellation.

Not while a DC current is flowing under Ohmic conditions.

Faced, with that, Johan went back to forbidding charge accumulation at this boundary, and claiming that it's obviously or axiomatically impossible. Even though he'd previously agreed with it.

Yes after thinking deeper about it I realised that I should not have given you the benefit of the doubt: And in future I will never do so again since you have consistently proved that you do not even understand Ohm's law.

 

[johanfprins]

Current density and charge density are different quantities, Johan.

Yes when a uniform current is flowing along an Ohmic circuit, the amount of charge flowing into and out of a volume is exactly the same, even though the charge-density within this volume stays constant since for each charge-carrier flowing out, you have a charge-carrier flowing in. When Ohm's law is valid, you always have the same total charge flowing through any cross-sectional area, so that the charge-density within any volume cannot be more, or less, than in another equal volume along the circuit.

It's utterly trivial to have any combination whatsoever of large/small/zero/negative current density and large/small/zero/negative charge density.

Not when Ohm's law is valid around the whole circuit.

This is not difficult, even for a non-mathematical non-physicist like yourself. Cars on a bridge have this property.

Identical cars moving at equal distances and at the same speed across a bridge cannot accumulate anywhere on the bridge. Stop talking nonsense!

 

[johanfprins]

Send me a PM if this actually happens. Otherwise, goodbye.

I hope that you will this time keep to your promise.

 

[johanfprins]

Because I've been reading the thread and attempting to understand what I read. You should try it.

You did not answer my question. Or did you just use the term "density" without understranding what it means?

 

[D'rok]

You did not answer my question. Or did you just use the term "density" without understranding what it means?

Mass per unit volume.

For example, when I sardined myself onto the subway this morning, there were, let's say, 200 people in the subway car with me. Take those same 200 people and put them on the subway platform and I wouldn't have to become close, personal friends with any of them.

In other words, the subway car was dense with humans; the platform was not.

There is also a lot of human density in this thread.

 

[johanfprins]

So what exactly do you mean when you say "charge-carriers" in these examples?

Read any book on Solid State Physics and you will see that they are wave-packets formed by the superposition of the delocalised waves which you obtain when solving Schroedinger's equation for an ideal metal.

They are not the same as a "free electron" outside the metal. In fact they are part of a single many-body Schroedinger wave which we tried to solve for by guessing the boundary conditions which apply. That is why Landau proposed the term "pseudo-particles". Where-as an ensemble of really free electrons can be considered as totally separate entities, the charge-carriers are not totally separate entities, since each one of them is a superposition of the same delocalised waves. For this reason it is naive to think that you can apply the laws of electrodynamics to them as if they are really free electrons.

To determine whether charge can accumulate at a metal-metal interface while a steady state current flows under Ohmic conditions, one must solve Schroedinger's many-body wave equation for the whole iron-copper-iron sandwich while an electric-field is present. Only in this manner will one be able to get a physically possible answer; since the spooky action at a distance is then included in the solution. This "spooky action at a distance" modifies the electrodynamic interactions within a solid. If you did not require the spooky action at a distance we would have been able to explain chemical bonding purely in terms of Maxwell's equations. We know that this is not possible.

 

[sol invictus]

Identical cars moving at equal distances and at the same speed across a bridge cannot accumulate anywhere on the bridge. Stop talking nonsense!

ben: "A does not imply B"

Johan: "A+B+C implies B. Stop talking nonsense."

???

Yes, Johan, we agree with you that if the charge carriers acted at all times like an absolutely rigid body of uniform density ("equal distance and same speed"), there couldn't be any accumulations of charge. That is tautologically obvious - it assumes the conclusion, in fact (since uniform density is what we are discussing).

Unfortunately for you, neither cars nor charge carriers behave anything like that, as anyone that has ever approached a toll plaza or charged a capacitor knows.

 

[D'rok]

Read any book on Solid State Physics and you will see that they are wave-packets formed by the superposition of the delocalised waves which you obtain when solving Schroedinger's equation for an ideal metal.

They are not the same as a "free electron" outside the metal. In fact they are part of a single many-body Schroedinger wave which we tried to solve for by guessing the boundary conditions which apply. That is why Landau proposed the term "pseudo-particles". Where-as an ensemble of really free electrons can be considered as totally separate entities, the charge-carriers are not totally separate entities, since each one of them is a superposition of the same delocalised waves. For this reason it is naive to think that you can apply the laws of electrodynamics to them as if they are really free electrons.

To determine whether charge can accumulate at a metal-metal interface while a steady state current flows under Ohmic conditions, one must solve Schroedinger's many-body wave equation for the whole iron-copper-iron sandwich while an electric-field is present. Only in this manner will one be able to get a physically possible answer; since the spooky action at a distance is then included in the solution. This "spooky action at a distance" modifies the electrodynamic interactions within a solid. If you did not require the spooky action at a distance we would have been able to explain chemical bonding purely in terms of Maxwell's equations. We know that this is not possible.

Why do you need to invoke quantum mechanics at all? Why can't you discuss these simple examples in terms of classical EM?

 

[johanfprins]

Johan,
Would you mind going into this in more detail when you get the chance, please? Could you, for example, explain the Elitzur–Vaidman bomb tester in terms of known properties and interactions of waves? I'd be very, very interested in reading that.

Yes I can. It has basically the same explanation as the double slit experiment. I do not really want to steer this thread away from superconduction, but will make a few remarks at this point.

The non-paranormal explanation is based on the assumption that the intensity of any hamonic wave is proportional to its energy as it has always been for all time. For a light wave it is the intensity of its electric and magnetic components which, when added up over the whole volume of a single-photon wave, is equal to (hbar)*(omega). The total intensity of a solitary electron wave in space is its mass and gravitational energy. Although it is a wave, its energy distribution is its mass: Therefore it has a centre of mass: Thus when it moves past you it moves like the centre-of-mass of any extended object moves. This does not make it a "particle" just as Jupiter is not a "particle" purely because its centre-of-mass is moving like a “particle".

A wave can only interact with another body when it resonates with the other body. For example when a radio-wave reaches an antenna with which it does not resonate it will not interact but just move on. So if you have many antennas there is a probability involved with which antenna it will resonate first. The same is true for light and electron waves. Thus the wave itself is not a probability distribution that is inbuilt in Nature.

Waves change shape and size (morph) when the boundary conditions change: If the boundary conditions change suddenly, this morphing is also sudden: It can cause the wave to collapse “instantaneously” or inflate “instantaneously” (Guth's inflation of our universe?). Thus, what is considered as quantum jumps by electron-"particles" is really the “instantaneous” morphing of waves.

When a photon- or electron wave morphs, it can morph into fragments which still stay in instantaneous contact with each other. Consider for example a d-electron wave around an atom. In other words an electron-wave is "entangled" with itself, no matter out of how many fragments it consists: The same for a photon-wave.

Consider, for example, an electron p-wave around a nucleus of an atom. It effectively consists of two separate lobes which do not interact with the nucleus since its intensity at the nucleus is zero. But since its intensity is its mass energy, its centre-of-mass which coincides with its centre of charge, is situated within the nucleus. That is why the atom does not “wobble" as it surely must if you have an electron-"particle" jumping around in a probabilistic manner.

Now, consider an electron approaching a double slit: It encounters new boundary conditions: It morphs into two lobes and passes through both slits: These lobes interfere and the electron morphs into the shape of a diffracted wave. When it reaches the screen it encounters millions of antennas: The first one it resonates with it collapses into and makes a spot. Thus after many identical waves have arrived at the screen the spots start to represent the intensity of the ensemble of diffracted waves.

Now you put two detectors behind the screen to detect through which slit the “particle” moved. The wave moving through both slits will collapse into the detector it first resonates with. The two lobes both disappear and we conclude that a “single particle: has moved through only a single slit. But after collapsing you do not have two lobes that can interfere anymore to form a diffracted wave distribution: So no diffraction pattern anymore.

In the Elitzur–Vaidman bomb tester, the photon actually splits up in two sub parts which however remain entangled. If the part that moves past the bomb resonates with the detector at the bomb, the whole wave (both parts) collapses and the interference pattern then disappears. When the sub-photon reaching the bomb does not resonate with the detector at the bomb, it will just move on; and the interference pattern remains. The only part that seems “paranormal” in this model is the entanglement of the two parts; but we know from experiment that this happens when more than one photon entangle. So it should also be the case whn a single photon splits into fragments. The only difference is that when the boundary conditions for two entangled photons change they can disentangle, while for a single photon the fragments can disappear while the single photon stays entangled with itself.

 

[Reality Check]

Consider, for example, an electron p-wave around a nucleus of an atom. It effectively consists of two separate lobes which do not interact with the nucleus since its intensity at the nucleus is zero.

Wrong: There is no p-wave. There is a wave function that descibes an electron in a p state. That is not a wave of any kind. In the Cophenhagen interpretation this gives a zero probability of the electron being at the center of the atom. In fact electrons in p orbitals have a finite probabity of being within the nucleus since it has a finte extent (d orbital electrons are even worse!).

Now, consider an electron approaching a double slit: It encounters new boundary conditions: It morphs into two lobes and passes through both slits: ...

All you are doing is rehashing QM combined with a fantasy that the wave function is an actual wave.

The problem is that you remain ignorant of the results of the Wheeler delayed choice experiement where the choice of what to measure after the particle passes through the slits determines whether there is interference or not.
In your world there would always be interference and this is shown wrong by the experiment.

Your waves cannot explain the Elitzur–Vaidman bomb tester results either.
In your world the bomb will explode 100% of the time as your wave is split into 2 parts and sent along the 2 paths. Evoking an imaginary 'resonance' will not help.

 

[johanfprins]

As usual you are going[off on a rant about somthing that I did not say.

I disagree. It has been you who consistently have gone off on a rant!

You called several things that are experimentally verified "paranormal".

I did not: Stop deliberately distorting what I argued. I did not call the experimental results paranormal but that the accepted interpretations of these experiments are paranormal. In fact the results are not paranormal since they can be explained purely in terms of waves without having to invoke the paranormal concept of "wave-particle" duality.

1. Wave particle duality: supported by experiments.
2. The double slit experiment: is an experiment !
3. Multi-world interpretation of QM is an interpretation.
4. Wheeler's delayed choice experiment has been actually done
   Jacques, Vincent; et al. (2007). "Experimental Realization of Wheeler's Delayed-Choice Gedanken Experiment". Science 315: 966-968. arXiv:quant-ph/0610241v1. Bibcode 2007Sci...315..966J. doi:10.1126/science.1136303.
5. That sounds like another QM interpretation (de Broglie–Bohm theory?).
6. Aharanov-Bohm effect: another experimental result
   Osakabe, N; et al. (1986). "Experimental confirmation of Aharonov-Bohm effect using a toroidal magnetic field confined by a superconductor". Physical Review A 34 (2): 815–822. Bibcode 1986PhRvA..34..815O. doi:10.1103/PhysRevA.34.815. PMID 9897338.

That is ignoring the scientific evidence about how the universe acts.

Another typical deliberate distortion from you. I am NOT ignoring the scientific evidence: I am just NOT accepting paranormal interpretations for the scioentific evidence as you are willing to accept: I am not superstitious like you when it comes to physics.

That makes it into a delusion (or may ignorance or maybe just being too lazy to do the research).

Stop trying to steal my line: It is you who are delusional and too lazy to think for yourself that real physics NEVER requires paranormal interpretations.

Back up this assertion, johanfprins: Provide a explanation of these experimentally verified effects:

• Quantum eraser experiment.

• If you are intelligent enough to have followed my explanation of the double slit experiment in terms of pure waves and wave interactions, you should be able to figure this one out for yourself.
  

  [*]Stern–Gerlach experiment (wow, intrinsic angular momentum, i.e. "spin").

  Angular momentum of a single charge cannot generate a magnetic moment. Again there is nothing wrong with the Stern-Gerlach experiment, but to interpret it in terms of the "spin of a single charge" is paranormal claptrap.
  

  [*]Elitzur–Vaidman bomb tester

I have summarised the solution in tems of waves above.

using the known properties and interactions of waves.
Start with the Stern–Gerlach experiment.

Both the photon and the electron's energy is in essence the same; or else a photon would not be able to entangle with an electron-wave to increase its energy. It is thus not surprising that an electron wave has a magnetic component: But this has NOTHING to do with any angular momentum at all.

How do waves give a particle an intrinsic angular momentum?

It does not give it an "intrinsic angular momentum" but a magnetic field component without requiring an "intrinsic angular momentum". I am discussing this in my book: And since this thread is about superconduction, I am not willing to post the whole chapter from my book which discusses "spin" on this thread.

We can explain it using QM but there are no "waves" involved - there are wave functions.

A wave function is a mathematical construct not a physics-concept. Physics require an interpretation of what the mathematical wave function represents. We cannot observe a wave function: Only its intensity; and in the case of ALL harmonic waves this intensity-distribution is a measure of the energy-distribution of the wave.

The Dirac equation gives particles intrinsic angular momentum because coordinate rotations of 360 degrees do not return to the original quantum state. Instead you have to rotate by 720 degrees. Noether's theorem then tells you that this rotation symmetry is equivalent to an angular momentum.

Interesting mathematics, but not physics at all!

As I have posted, this thread is about superconduction and I do not want to become involved in long discussions about the Dirac equation and Noether's theorem at this point. In fact I am doing further research on deriving the correct differential wave equation for an electron from Maxwell's equations: Such an equation will thus be commensurate with special relativity, BUT it is NOT Dirac's equation. Since my ideas on this are still on a learning curve, I do not want to argue them on a thread at this stage, and especially not with a person like Reality Check who is fast becoming a W D Clinger, on these issues. My present ideas are summurised in my book.

Furthermore, I am nowadays spending almost all of my time on this thread: In two weeks time I am going on an overseas trip which requires my attention. From now on, and while I am overseas, I will not be able to spend as much time posting on this thread: However, in the interest of the future of physics I will answer all posts in sequential order when time permits.

 

[Probably Not]

In the Elitzur–Vaidman bomb tester, the photon actually splits up in two sub parts which however remain entangled. If the part that moves past the bomb resonates with the detector at the bomb, the whole wave (both parts) collapses and the interference pattern then disappears. When the sub-photon reaching the bomb does not resonate with the detector at the bomb, it will just move on; and the interference pattern remains. The only part that seems “paranormal” in this model is the entanglement of the two parts; but we know from experiment that this happens when more than one photon entangle. So it should also be the case whn a single photon splits into fragments. The only difference is that when the boundary conditions for two entangled photons change they can disentangle, while for a single photon the fragments can disappear while the single photon stays entangled with itself.

But this doesn't align with the experimental results, does it? As Reality Check said, if a photon were to "split into two sub parts", why wouldn't the functional bomb trigger 100% of the time rather than 50% of the time. Why would the interference pattern vanish from the tester's output when a functional "bomb" is present, even when the bomb's detector does not intercept a photon?

 

[johanfprins]

JFP:Originally Posted by johanfprins
You think that after you have published one manuscript which was written by you supervisor and got one citation (probably by somebody else who also studied under the same supervisor) you can teach me physics!

RC: How idiotic. The fact that you do not even know how to apply Gauss's law to the Cu-Fe_Cu sandwuch shows that you are incapable of learning physics.

It seems that you will never catch on: It is not about “knowing how” to apply Gauss’ law, but about whether one can apply classical electrodynamics to a system that is modelled by Schroedinger’s many-body differential equation.

For a metal, the latter equation is solved under the assumption that during a steady-state, the negative and positive charges screen each other. When an Ohmic current flows through a circuit, you have such a steady-state at every cross-sectional area: Also a cross-sectional area between two different metals. Thus the change of electric-field across such an interface cannot be ascribed to an accumulation of charge-carriers within such an interface. An accumulation is only possible when the charge carriers cannot flow everywhere along the circuit with the same current I.

You remarks just make your ignorance of scientific publishing obvious.

Read the paper: Effect of localized spin fluctuations on transport properties in the one-band Wolff model

Who is the first author?

That still does not mean that you have been the primary brains behind the paper.

I wrote the paper together with my supervisor. I would guess that you got at least one paper form you thesis - can I assume that your supervisor wrote it since you do the same?

To some extent yes: After publishing two joint papers with my supervisor, I was definitely not so arrogant to claim that I am an expert in writing papers until after I have at least published my first solo paper; of which more than 60 then followed. I knew that there was still a hard slog ahead; and would definitely not have thought that I have the ability to “check” the “reality” of people who are obviously light years ahead of me. If I had stopped where you have stopped in publishing, I would have remained very-very humble.

It actually has been cited twice - and yes my supervisor was the sole author on one and a contributing author on another.

Will you give the names of the authors of the two papers who cited you?

JFP:
Originally Posted by johanfprins
I do not stop them: Nature stops them since, even while they transport a current, they remain at the lowest energy that they can be at: They have no energy to dissipate.

RC: That is ridiculus. They have kinetic energy (they are moving!) So they do have "energy to dissipate".

If they have energy that can dissipate, they cannot transfer a superconducting current. READ MY MODEL on my website: The kinetic energy is supplied by quantum fluctuations and therefore it is not kinetic energy that can dissipate.

But that is not the question: johanfprins: How do you stop your charge-carriers from scattering?
JFP:
Originally Posted by johanfprins
The charge carriers within any conductor are NOT electrons.

RC: And once again: nothing to do with my question: johanfprins: What are your charge-carriers?

I have answered this many times AND it is on my website: Let me do it again: They are localised waves (orbitals) like those you find in an insulator after a metal-insulator transition.

The charge carriers within any conductor can be electrons.

Nope! An electron cannot have less energy than its rest mass energy m_e*c². The charge-carriers within a metal with work function W has an energy of m_e*c²-W: This is less than the lowest energy an electron can have.

The charge carriers may also be electron holes, ions (e.g. electrolytes) or even protons (e.g. solid electrolytes).

Here you go overboard again. We are talking about metals for which Ohm’s law is valid. The charge-carriers are then negatively charged wave-packets (pseudo-electrons): NOT actual electrons.

JFP: In my model, the charge carriers within all superconductors are localised electron-states which have the lowest energy that they can have.

RC: That is idiotic: As you state - you now have an insulator!

Firstly you ask me what my charge-carriers are; and then you suddenly remember what they are: Why did you then ask in the first instance? Stop playing games! All superconductors must first become insulators before they can super-conduct.

Why do you think the ceramics form a Mott-type insulator, with localised, anchored, electronic-orbitals, before they become superconducting at a lower temperature? The required charge-carriers are forming within this temperature interval (pseudogap), but their density is too low to super-conduct. By cooling further, their density increases until it is high enough for superconduction to occur. Owing to the different electronic energy spectrum in metals, the density of localised states is already high enough when the metal goes through the required metal-insulator transition, to transfer a superconducting current. Therefore, in this case, there is not a pseudogap as is measured in the case of the ceramics.

JFP: When the density of these localised states becomes high enough, they can exchange places by means of quantum fluctuations.

RC: Wow - mysterious "quantum fluctuations"!
But this sounds like vacuum fluctuations

Yes it does sound like “vacuum fluctuations”: The latter does not exist since the fluctuation in energy can only occur whithin a matter wave with mass-energy: Not without a matter wave being present.

which have their own problems for your idea (see below).

These “problems” are only within your mind.

Since the energy during a quantum fluctuation is used (to move on) and it then disappears, the charge-carriers have the same potential energy when they reach the target contact than the potential energy they have started off with from the injection contact.

Wrong: You now have "charge-carriers" within the superconductor that ignore any electric field.

Correct! This is exactly what you MUST have in a superconductor, or else the charge-carriers will be accelerated to gain energy; which demands that the potential energy at the injection contact and the ejection contact MUST BE DIFFERENT: This means a non-zero voltage across the contacts an thus NO SUPERCONDUCTION.

They go off in random directions., i.e. there is no current!

Not when you inject charge carriers at a contact. When you inject charge carriers, the energy of the total ensemble of charge-carriers increases, and therefore the ensemble must then eject charge-carriers at the other contact in order to keep the energy of the whole ensemble at the lowest level. This is the ACTUAL reason why you have superconduction.

Let me try and explain it in simpler terms with the hope that you can grasp the situation: Assume that the superconducting phase is a black box so that we do not really know what is going on within it. What we know is that when we inject charge carriers into the box at an injection contact, an equal number of charge-carriers eject at the ejection contact having THE SAME POTENTIAL ENERGY . This is obviously NOT possible if the charge-carriers have been accelerated within the black box. Thus any mechanism required to model superconduction MUST explain how the charge-carriers injected at the injection contact causes an equal amount of charge-carriers, which have the same potential energy, to be ejected at the other contact. This means no acceleration.

Really wrong: vacuum fluctuations create virtual particles.

Yes “vacuum-fluctuations” are themselves virtual: But even if you want to claim that quantum fluctuations are the same as “vacuum fluctuations”, then it still supports my model, since the energy they represent appears, to move the charge-carriers along, and then disappears: The potential energy of the charge-cvarriers thus remains the same and there is thus no increase in kinetic-energy which can dissipate as entropy. Exactly as it must be when you have superconduction.

Furthermore, if the ground-state energy of the superconducting phase must increase in order for a current to flow, the superconducting phase must be increasing its energy to be more than its ground-state energy. This means that it has gained energy that can dissipate: And the most important law of physics is that when you have energy that can dissipate IT WILL DISSIPATE. When a current flows by dissipating energy, it cannot be a superconducting current EVER. Simple high school physics my boy!

These can never be real particles unless energy is provided.

Exactly! This is why “these virtual particles” can supply the required energy and disappear before this energy decreases the potential energy and thus dissipates as entropy.

So your charge-carriers can never leave the superconductor. But currents do flow through superconductors!

When you inject charge-carriers at one contact, charge-carriers MUST eject at the other contact for the superconducting phase to maintain its lowest energy. Therefore a current will flow!

JFP:
Originally Posted by johanfprins
Nope! No matter whether the charge-carriers are fermions or bosons, if you can accelerate them, you create states into which the can scatter.
...snipped rant about acceleration...

RC: That is ignorant. The available states are created by the quantum system, not the ability to accelerate particles.

Now you suddenly want to remember that quantum mechanics plays a role. Why now only, when you totally ignored this when you claimed that Gauss’ law, which is a classical law, can be applied to a quantum system? You are really hilariously funny.

Obviously, if there are not energy states within which the charge carriers can be accelerated, they will not accelerate. But you claim that they are being accelerated: Thus, in your model there must be such states and therefore the energy of your charge-carriers must increase when a current is flowing. This means that their potential energy must decrease on their way from the injection contact to the ejection contcat, and that they must dissipate the kinetic energy that they have gained: They can therefore not transfer a super-current. In fact in one of your previous posts you clearly stated that there are not such energy levels available for Cooper pairs, and now you claim that Cooper pairs are being accelerated, which mandates that there must be such energy levels available. Please make up your mind, and start to argue sense!

 

[johanfprins]

Think about it this way - take a slinky. Stretch it out evenly so that there is a constant density of coils. Now compress it slightly at some point. There is now 2 different density of coils. There has been an accumulation of coils at that point.

Absurd! When the same current I flows through all interfaces along the circuit there cannot be any accumulation of charge anywhere along the circuit.

 

[johanfprins]

As usual you are displaying appalling ignorance.
This has beened explained to you many times before. the different charge density ("accumulaton of charge") is created when the current is switched on. All the current does in the steady-state case (and as pointed out before by me) is add an amount of charges to one side of the interface and subtract the same amount of cjarges from the other.

You are arguing that a transient, non-equilibrium distribution of charge will remain after equilibrium has bee extablished. Stop posting nonsense.

The Cu-Fe-Cu sandwich example explicitly gives a different charge density at the interfaces from the body of the layers. This is an accumulation of charge at the interfaces.

This is your deduction after applying classical electrodynamics to a many-body quantum state; as if the latter is a classical system. Can you explain to me why this is possible? Quantum mechanics was founded specifically because the classical laws do not apply anymore. If you know both classical electrodynamics and Schroedinger's wave mechanics you will know that you are wrong; as usual!!

I am skipping your follow-up post since it has been answered already!

 

[johanfprins]

Originally Posted by johanfprins
JFP:You have me confused. Was the height of the water the same on both sides?

D'rok: Yes.

Then there cannot be any accumulation of water between the two sides.

JFP: But in either case this example has nothing in common with water flowing through pipes that are filled with water which cannot compress nor with charge-carriers flowing through conductors which repel each other when pushed together to in this manner also be incompressible.

D'rok: I gather from what I have read in this thread that "water through pipes" is not the correct analogy and is artificially limiting.

When Ohm's law applies, pipes are a better approximation than your tree blockong the flow along a street.

 

[johanfprins]

If charge carriers are incompressible, then how can there ever be an accumulation of charge?

It is not impossible to have charge-carriers accumulating. This happens when you have a capacitor within the circuit; and also Solid State diodes and transistors. The reaction of the circuit is then NON-Ohmic. It is, however, impossible for accumulation to occur when Ohm's law applies along the whole cicuit. An equilibrium current flows uinder these conditions and under equilibrium conditions identical charges will stay as far away from each other as they can.

 

[johanfprins]

In the water analog, pressure head is the equivalent of voltage.

Within a pipe the pressure is, according to Pascal, everywhere the same: When a current flows through a resistor, the potential energy is higher on the one side than the other side of the resistor.

In a gravity field, tilting an open container of water creates a pressure differential, which is the analog of a voltage differential.

No it does not create a pressure differential, it creates a gravitational energy differential.Yes the latter is more akin to a voltage differential across a resistor.

As many others have stated (better than I), this does not follow. You're assuming that the circuit was always in the steady state, but that's demonstrably false.

I have not assumed that the "circuit was always in the steady state". The "many others" asume that you can retain a non-steady-state accumulation after the circuit has relaxed into an Ohmic steady-state: This is unadultertaed claptrap.

So the charge carriers are compressible?

Not while a steady-state Ohmic current is flowing.

I agree that one gets a charge buildup due to transient current flows; I don't see why that can't be the case in Fe:Cu:Fe sandwich circuit.

It is, however, claimed on this thread that if there is such a non steady-state charge buildup, this charge buildup will remain after the circuit has relaxed into an Ohmic steady-state: The latter is impossible.

What constitutes a 'barrier?' A 1 ohm resistor? A megohm?

A resistor is not a barrier: The interface between two metals is NEVER a barrier, since the Fermi-levels of the two metals align. Thus the potential energy of the charge-carriers are exactly the same on both sides of the interface

Since the world lacks perfect insulators, wouldn't it follow that there's always a small amount of current flowing if there's any voltage difference, and therefore there can never be any charge accumulation?

No it does not, since the Fermi-level of an insulator always falls within a region where there are not delocalised waves which can superpose to form free charge-carriers with the same energy that the charge-carriers within the metal has. Therefore, even though you can have a leakage current, there is a barrier. This can also be demonstrtated by plotting the current I as a function of the voltage V. You will not get a linear relationship as you will when Ohm's law applies.

What about an imperfect, leaky capacitor? Based on my personal (painful) experience, an imperfect capacitor can hold quite a large charge.

Exactly! Although the capacitor is leaky, there are not free charges at the position of its Fermi-level. The leakage current is caused by a totally different mechanism involving a combimnation of hopping and dielectric breakdown. Thus, the free charges moving from the metal into the insulator experience a barrier to their motion since there are not charge-carriers within the insulator that has the same energy as the charge-carriers within the metal.

Let me repeat again: Current flow through materials can ONLY be modelled in terms of Schroedinger's wave mechanics; and to think that the classical laws of electrodynamics then also apply as if the current exists of individual free charges, as in the case for free electrons within a vacuum, is just plain nonsense. A person who reasons like this, just do not understand the most elementary aspects of modern physics.

 

[johanfprins]

I suspect this is the root of the problem. It looks to me like you studied yourself into a misunderstanding of the subject. It isn't possible to overturn a discipline that you don't completely understand - i.e., I don't think you are equipped to distinguish between errors and radical new discoveries.

I will not dare to insult another person like this unless I do understand the physics involved: Which you do not and never will be able to understand!!

The typical arrogance I have always experienced when I have had to deal with a lawyer!