Superconductivity at room temperature??

[Ziggurat]

You see this is the type of irrelevant remark that gets up my nose. What it implies in terms of the discussion so far is that you believe that a charge-carrier in a superconductor can accelerate uphill against the gradient which is responsible for generating the force.

I suggested nothing of the sort. If a particle slows down, that is still an acceleration.

Under conditions for which Ehrenfest's theorem applies, you are correct. But in a superconductor the experimental evidence is compelling that the charge-carriers are moving under conditions for which Ehrenfest's theorem does not apply.

There ARE no conditions under which Ehrenfest's theorem doesn't apply, except when quantum mechanics doesn't apply. You have yet to explain why any such conditions invalidate Ehrenfest's theorem and hence quantum mechanics.

Oh yes it does depend on boundary conditions! It only applies when the boundary conditions are such that a gradient in the potential energy function is present. When this is not the case, Ehrenfest's theorem need not apply.

In the mathematical sense (and Ehrenfest's theorem is a mathematical theorem about the theory of Quantum mechanics), a potential energy gradient is always present, even when it's zero. And Ehrenfest's theorem has no problem dealing with a zero.

According to you it must still apply for a stationary wave.

Of course it does. You will search in vain for any stationary state that violates it. Shall we go through the calculations, johan? Want to try the ground state of a harmonic oscillator? Perhaps an excited state? Or perhaps you want something more complex, like a hydrogen electron orbital. Just let me know, and we can walk through the calculations, and show that it DOES apply to stationary states.

Semantics, semantics, semantics.

It's not semantics at all, it's math.

I have claimed all along that the charge-carriers within a superconductor move without accelerating

And you have done so on the basis of a claim which is not true.

The energy increase which is required to move over a barrier without acceleration cannot exceed a time interval (delta)t as limited by (delta)E(delta)t=g(hbar) where the value of g is determined by the equilibrium-energy, size and shape of the wave. For a Gaussian "zero-point" wave g=1/2. So I do know!

No, you do not. That is not how the energy-time uncertainty principle is defined. I suggest you read an introductory textbook, such as Griffiths' "Introduction to Quantum Mechanics". Quoting from Griffiths, (pages 116-118, 2nd ed), who goes through a mathematically rigorous derivation of the relationship so you can prove that it means what he says it means (emphasis his),

"(delta)t represents the amount of time it takes the expectation value of [some observable] Q to change by one standard deviation. In particular, (delta)t depends entirely on what observable (Q) you care to look at - the change might be rapid for one observable and slow for another. But if (delta)E is small, then the rate of thance of all observables must be very gradual....
...
It is often said that the uncertainty principle means energy is not strictly conserved in quantum mechanics - that you're allowed to "borrow" energy (delta)E, as long as you "pay it back" in a time (delta)t ~ hbar/(2(delta)E); the greater the violation, the briefer the period over which it can occur. Now, there are many legitimate readings of the energy-time uncertainty principle, but this is not one of them. Nowhere does quantum mechanics license the violation of energy conservation, and certainly no such authorization entered into the derivation of Equation 3.74 [the energy-time uncertainty relation]."

I cannot "invent" experimentally incontrovertible results

But you can, and have, invented incorrect interpretations of those results.

You just argued that voltage measurements cannot be used to prove superconduction.

Indeed, they cannot. For one thing, they can only provide evidence (not proof) of zero resistivity, and for another, you need the Meissner effect or it's not superconductivity, even if the resistance is zero.

In my experiment I do not need to do such experiments, even if I could do them, since the physics that is used to model electronic interfaces, and thus chips, demands that the voltage within my phase must be exactly zero. In fact, my experiment is the first ever that proves directly that the voltage is actually zero. It is the best proof ever that a current can be flowing with zero voltage.

And yet, nobody believes you. How sad.

How did Onnes measure the resistivity without being concerned about voltage or an electric-field? And since zero resistivity has NEVER been defined before, or after, Onnes discovered superconduction, it will be enlightening to us all on this thread if you would be so kind to give us a definition of zero resistivity: Please indulge us.

First off, that's clearly not correct, as basically ANY definition (even a bad one) for resistivity will naturally include the case of zero resistivity. And since resistivity (not voltage) is what Onnes reported, clearly he had a definition, and there's no reason to think or suspect that he didn't have an idea of what it would mean for resistivity to be zero.

And second, I already gave you a definition in this thread for resistance, which also covers the case of zero resistance. You seem to have forgotten, but what you asked for (and you asked for it before) has long since been provided. If you really care about the distinction between resistance and resistivity, we can extend that definition to resistivity rather trivially.

But to emit EM radiation this need not be so: Acceleration perpendicular to velocity will still cause radiation to be emitted.

No, johan. CAN, not will. I have given you an example where it does not.

Do you know about energy conservation? It seems not at all. Accelerate a charge-carrier from the injection contact to then target contact and it will gain kinetic energy V=(1/2)mv^2; where V is the voltage difference.

This is trivially wrong: the units on the two sides of the equation don't agree. Care to correct your rather elementary mistake and try again?

Another semantic cheap shot. The fact that you can argue thus, does not imply that Ehrenfest's theorem always applies for a stationary wave. Ehrenfest did not consider a zero gradient when he derived his theorem.

The derivation of the theorem applies regardless of whether the gradient is zero or not. At no step anywhere within the derivation does it depend on a non-zero gradient, so it applies regardless of what the gradient is. And it DOES apply to stationary states. I will repeat my challenge: we can take any stationary state you like, and prove that it holds for that state. Hell, for symmetric potentials, it's as trivial a problem as it gets.

You are using "the trivial" in an attempt to avoid talking real physics.

No, I'm not. I'm quite willing to do the math with you, if you actually care, and then I can show you that it's trivial.

I have described the process not well enough initially and admitted that you could have concluded that I am claiming more radiation than the energy that is available. So you do not accept this admission? Once a man has made a mistake you are a bully who will keep on kicking him even after he admitted that he was wrong?

I have not previously seen this admission. Just as you apparently did not see my previously provided definition of resistance (although actually I think you did, but just forgot). So what's your explanation? Since radiating 2qV per photon requires that only one photon be emitted per two electrons (otherwise energy conservation is violated), how do you explain it more simply than the charge carriers being pairs of electrons?

I have since corrected the mistake AND placed the corrected version on my website AND explained it in the simplest terms possible, AND i will keep on doing so in the hope that the penny will eventually drop; even though you have proved that you are not very competent to handle real physics. I consider it my duty to explain physics over and over again until a person can understand it; even when the person involved is slow to grasp science.

It's quite peculiar that after admitting a mistake I called you out on a long time ago, you insist on saying that I'm the one who is not competent to handle real physics. That's a violation of the first rule of holes, johan.

 

[Skwinty]

A few years ago they demonstrated electrons moving in this manner around a nucleus, and all the electrons radiated: They call these "atoms": "Rydberg atoms".

Keep racking them up: the Rydberg atom is not one of the nonradiating solutions. It is, rather, one of the radiating solutions, with the E and B fields varying in time.

Am I going insane here or are you you both in agreement here, but just disagreeing for fun?

 

[sol invictus]

Please explain to me why there is such discord amongst all you clever people.

The only discord is between Johan and everyone else. I agree with everything Zig and ben have posted here (at least everything I've read, which I must admit isn't everything).

In cases where I disagree with Zig or ben - which has happened multiple times before on this forum - we have a simple way of settling our disagreements. We present mathematical arguments, refer to the literature if need be, and discuss experimental evidence - and sooner (or rarely, later), one of us agrees the other is correct.

With Johan this method fails. He doesn't understand mathematical arguments, he ignores references to the literature (which he evidently regards as mostly wrong), and he draws invalid and unjustified inferences from the experimental data.

Why is that? I think the psychology paper I posted earlier is a partial answer to that question.

Johan's posts fit a pattern we've seen over and over again on this forum: a lone individual that can't do math and doesn't understand basic physics decides everyone else is wrong about something. When his ideas aren't accepted, he interprets that as an attack due to the mainstream's fear that its ideas are wrong (which by the way is a classic example of psychological projection, where you attribute your own fears to others).

Pointing out mistakes in his assertions simply cements his beliefs further - he either regards objections as nitpicks that distract from the main point (and confirm his belief that the mainstream is trying to avoid engaging), or he cannot understand them, which he attributes to them being nonsense (again, confirming his beliefs). I don't think any amount of discussion will ever change that - certainly not discussion about physics.

 

[ben m]

Am I going insane here or are you you both in agreement here, but just disagreeing for fun?

Skwinty: Johan has made the claim that all accelerating charges radiate. (All A are R)

He is trying to prove this by showing examples of accelerating charges that radiate. (X is A and X is R)

I agree that some accelerating charges radiate. I agree with some of Johan's examples of such charges, including this one.

However, there are also counterexamples. The spinning disk Y is A, but not R. This disproves Johan's original statement.

For an analogy: Johan says "All armadillos are rabid". To prove this, he posts examples. "Here is a rabid armadillo. Here is another rabid armadillo! Everyone knows this armadillo is rabid, too." I agree that those three armadillos are rabid. However, I can show you one non-rabid armadillo---therefore not all armadillos are rabid, and the statement "all armadillos are rabid" is false. You can't make it true by showing me more rabid armadillos.

 

[Ziggurat]

For an analogy: Johan says "All armadillos are rabid". To prove this, he posts examples. "Here is a rabid armadillo. Here is another rabid armadillo! Everyone knows this armadillo is rabid, too." I agree that those three armadillos are rabid. However, I can show you one non-rabid armadillo---therefore not all armadillos are rabid, and the statement "all armadillos are rabid" is false. You can't make it true by showing me more rabid armadillos.

Part of me wants to believe that all armadillos are rabid. Sadly, this is mere wishful thinking on my part.

 

[Skwinty]

Thanks Sol and Ben.

In any event, the probability of me going insane = 1.

 

[ben m]

Sol, that's one of the reasons I want to cut off the "acceleration" discussion. Johan isn't interested in opening up Jackson to see the E&M side of things.

He thinks that the quantum side behaves very differently, but I have no interest in talking about it with someone who objects to the words "probability", "expectation value", and "particle". Maybe some other time?

However, I think we do have a slim chance of making progress on the energy-conservation problem. Johan, are you interested in getting back to that? Can you walk us through the energy budget of an electron going through your battery (gaining U = qV), through your radiating Josephson junction (radiating E = 2qV) and around and around? You say it picks up +qV from "polarization", but that energy can't be coming from the battery.

 

[sol invictus]

However, I think we do have a slim chance of making progress on the energy-conservation problem. Johan, are you interested in getting back to that? Can you walk us through the energy budget of an electron going through your battery (gaining U = qV), through your radiating Josephson junction (radiating E = 2qV) and around and around? You say it picks up +qV from "polarization", but that energy can't be coming from the battery.

Johan and I agreed on one thing early on - that if we could agree on precisely that issue, we'd never agree on anything. It's the simplest and most fundamental of the many mistakes Johan is making, so in that sense there is the greatest chance of progress there.

Even so, I think that chance is close to zero.

 

[Skwinty]

2eV made more sense as it is the energy of 2 electrons (cooper pair).

 

[ben m]

ground --- power supply ----------- junction ---------- ground

                                    ___   
                                    |    |
                                    |    |
                                    |    | 
                  __________________|    | . .  . . . . .  V 
                 /                       |
________________/                        | ..............  0 
                                         |
                                         | __________ -V

Re-quoting my earlier diagram of your circuit (copied from your erratum) just to get that ball rolling again. Johan, this is an unwrapped version of a loop circuit showing a battery whose voltage is V, connected to a junction that will produce photons of 2qV. An electron on the right has a potential energy (due to the so-called missing "polarization energy") lower than the potential energy I've labeled "ground". How does such an electron get back up from right to left, i.e. from below-ground to ground? It must do this to close the circuit. But the battery doesn't do it (the battery, shown, is getting it from 0 to +V) and there is no other energy source.

I'll repeat my answer: You're wrong, the circuit diagram (again, from your erratum) is nonsense. The energy loss in traversing the junction is the same as the energy gain in traversing the battery, not twice that.

 

[johanfprins]

Most physicists believe superconductivity occurs because of the formation of Cooper pairs (electrons which bind with each other), thus allowing the charge carriers (the pairs, not individual electrons) to obey Bose statistics instead of Fermi statistics.

So they only have to obey Bose statistics and presto you have superconduction? No my friend they must form a lowest energy macro quantum mechanical ground-state, whatever statistics they obey.!

If Cooper pairs form, then zero resistivity is a natural consequence.

Not true, even if Cooper Pairs did exist, they can only form a superconductor after the electron-pairs have really formed a Bose-Einstein Condensate: The latter requires that the pairs entangle to form a single, holistic macro-wave: Just like photons entangle to form a single holistic laser beam. There is no compelling physics-reason that under the conditions where pairs can be treated as separate charge-carriers, as Cooper Pairs are treated, they must superconduct.

The difficulty is that to form these pairs, you need the electrons to attract each other, even though Coulomb repulsion is trying to prevent pair formation.

This is not a great difficulty: Electrons do it every day when they form covalent bonds; and they even form as four-partners and as six-partners. The one thing they probably never do is to form pairs by the Cooper mechanism.

BCS theory was basically a description of how lattice vibrations could provide a mediated attractive force between electrons that could allow them to form Cooper pairs.

But it is ufortunately not how the charge-carriers are formed.

For high-Tc materials, this description seems to break down, meaning that some other pairing mechanism is responsible, even though it hasn't been identified.

It is breaking down since pairing is not required for superconduction to occur within these materials. A single mechanism models all superconducting materials (except the one I extracted from an n-type diamond) and it does not require any pairing.

But it's still a pairing mechanism which is believed to be responsible in all cases.

Have you observed pairs in the ceramics to make such a bold statement? This is what amazes me about you Ziggurat, you just ignore all experimental evidence to proclaim what you want to believe.

And the strength of the pairing mechanism is what determines Tc.

T_C is jointly determined by the binding energy of localized electron-orbitals, which in most cases are singly-charged, and the distances between them

The difficulty with room temperature superconductivity is that nobody knows if it's possible to get a pairing mechanism strong enough.

It seems to be possible since this is most probably what occurred when I extracted electrons from an n-type diamond: The extracted electron density seems to have first formed electron-pairs, similar to how electrons pair to form covalent bonds, so that these pairs could then entangle to form an actual Bose-Einstein Condensate within which these initially separate electron-pairs lose their individual existences completely. In all the other superconductors discovered to date, pairing most probably did not occur, and is not necessary that it must occur when the current is transported by electronic charge-carriers

johan, on the other hand, doesn't think that superconductivity of any kind involves Cooper pairs.

At least for once you have posted something I can agree with!

Well, here we have two models: One claims pairing is a must, while the other claims it is not necessary, since all superconducting materials discovered to date (except the one I extracted from a diamond) can be accurately modeled in terms of a single mechanism which do not require pairing. In a normal physics-world, the two models would be allowed to be known to everybody so that it can be decided by experiment which one is correct, or at least give a better fit to experimental data. But this is not allowed in the 21st century: The alternative model claiming that pairing is not necessary, must be suppressed as blasphemy at all costs and the person who claims it must be attacked viciously without first reading what he has actually done (just like Sol Ben and Ziggurat are doing on this thread): The reason for this attitude, which has been given to me many times during the past ten years, is that "the BCS model fits the low temperature metals so well that we do not need another model". This was even written to me personally by Josephson himself. What is different in this attitude than when they told Galileo that "Ptolemy's model explains everything so well that we do not need another model"?

When I have time I will keep on coming back and answer all posts (except those that are really just too crackpot to even contemplate) on this thread.

 

[Skwinty]

Johan,

What is the difference between a holistic macro wave and a density wave.

Once again I link to this paper:

http://www.physorg.com/news189798601.html

ETA: The comments to this article even make reference to you.

ETA2: I see you posted to this discussion. I will read all the comments.

 

[sol invictus]

But it's still a pairing mechanism which is believed to be responsible in all cases.

Have you observed pairs in the ceramics to make such a bold statement? This is what amazes me about you Ziggurat, you just ignore all experimental evidence to proclaim what you want to believe.

What amazes me about you, Johan, is that your reading comprehension is nearly a poor as your grasp of physics.


Incidentally, there is a typo in my last post:

Johan and I agreed on one thing early on - that if we could agree on precisely that issue, we'd never agree on anything. It's the simplest and most fundamental of the many mistakes Johan is making, so in that sense there is the greatest chance of progress there.

should read "Johan and I agreed on one thing early on - that if we couldn't agree on precisely that issue, we'd never agree on anything."

 

[ben m]

The alternative model claiming that pairing is not necessary, must be suppressed as blasphemy at all costs and the person who claims it must be attacked viciously without first reading what he has actually done (just like Sol Ben and Ziggurat are doing on this thread):

Johan, I haven't gotten anywhere near attacking your pairing mechanism, or lack thereof, or whatever. Things I've disagreed with:

a) your energy budget (and I was right) for a standard Josephson junction
b) your "corrected" energy budget for a standard Josephson junction
c) your misuse of classical E&M to "disprove" the BCS model
d) your misuse of quantum mechanics to get around (c)
e) your understanding of basic induction, EMF, etc.
f) your fuzzy descriptions of your experimental data, and the absence of any measurements other than I-V curves vs. gap size.

I have no idea what your new model is and I have no intention of attacking it. All I know is that your rejection of BCS theory relies on many utterly fallacious arguments.

 

[johanfprins]

That gets you an energy QV. But You're claiming an energy 2QV. You still haven't resolved this energy conservation violation.

I will admit that I can see your problem: You have never really thought about what an additional voltage V_J over a Josephson junction really implies. Without going into the details of how the circuit is changed to place an extra voltage V_J over the junction, let us start off with a SIS without this voltage and having a voltage V_source over the SIS. When it is in a superconducting state, the applied electric field caused by V_source is cancelled everywhere within the SIS structure. This is proved by the fact that when you increase the source voltage V_source from zero, the current increases without any voltage increase over the junction. This would be impossible if the charge-carriers were accelerated by the applied voltage through the SIS system; and thus proves that what Ziggurat is proclaiming is nothing else but unfounded fairy tales.

Now you place an additional voltage V_J to the source voltage V_source over the junction. This does not change the source voltage over the two contacts to the SIS (yes this is amazing but has been proved over and over again for a SIS system which allows Josephson tunneling as just described above) and can therefore only be accommodated if the voltage drops on both sides of the junction adjust in order order not to change V_source over the SIS.

Just try the experiment yourself, instead of pontificating that theoretical physics is sufficient on its own. Thus, the electric-fields active on both sides of the junction must now be different. This demands that the polarization energy of the orbitals on the low energy side of the junction must decrease by qV_J (see my calculation on my website) in addition to the decrease qV_J that would be there if there were no polarization energies involved.

Yes, the fact that an extra voltage over a Josephson junction acts like a separate source input always amazed me; even when I still believed in the fallacy of Cooper Pairs. But this is the experimental fact; and I believe in experimental facts and not in pie-in-the-sky imaginary rotating discs and infinite ropes consisting of a single charge; even when the proponents claim behind anonymous masks that they are highly recognized and able physicists.

 

[Ziggurat]

So they only have to obey Bose statistics and presto you have superconduction?

Well, no. There's more to it than that. But when describing the difference between standard theories of superconductivity and your ideas, that was sufficient.

But it is ufortunately not how the charge-carriers are formed.

And that is the point of contention between you and standard theories. The point of that post was to describe the difference between your ideas and standard theories. Obviously, if standard theories are wrong then what I said isn't what really happens (that should go without saying), but what I said is still a good description of standard theories.

Have you observed pairs in the ceramics to make such a bold statement?

What bold statement? That most physicists believe high-Tc materials still superconduct via Cooper pairs? That's not a bold claim, that should be an obvious claim to anyone who has paid any attention at all. Hell, that claim is correct even if no such Cooper pairs exist. Remember, the claim is that this is the standard theory, and my description of the standard theory is correct even if the standard theory is not.

The alternative model claiming that pairing is not necessary, must be suppressed as blasphemy at all costs and the person who claims it must be attacked viciously

Your victim act is wearing thin.

What is different in this attitude than when they told Galileo that "Ptolemy's model explains everything so well that we do not need another model"?

If that's all they had done with Galileo, it wouldn't have been a problem. But they did quite a bit more than that. When you want to play the martyr by drawing on historical analogues, it helps to actually have some idea of what actually happened.

"They laughed at Einstein. They laughed at the Wright Brothers. But they also laughed at Bozo the Clown." - Carl Sagan

 

[Ziggurat]

I will admit that I can see your problem: You have never really thought about what an additional voltage V_J over a Josephson junction really implies.

There is no additional voltage. There is, and only ever was, one voltage across the junction. You cannot have two different voltages across the same junction. You can CHANGE V if you want to, but there is still only one V.

Without going into the details of how the circuit is changed to place an extra voltage V_J over the junction, let us start off with a SIS without this voltage and having a voltage V_source over the SIS. When it is in a superconducting state, the applied electric field caused by V_source is cancelled everywhere within the SIS structure.

In which case, you HAVE NO VOLTAGE across the SIS structure. No electric field, no voltage. Maybe you've got voltage at your battery, but you don't have it across your SIS if the field is cancelled. What on earth do you think voltage is?

Now you place an additional voltage VJ to the source voltage Vsource over the junction. This does not change the source voltage over the two contacts to the SIS (yes this is amazing but has been proved over and over again for a SIS system which allows Josephson tunneling as just described above)

Yeah, um... no. There is ONE voltage across the junction itself. And if this voltage VJ is different than the voltage Vsource applied to the entire SIS system, then that means you have a voltage difference WITHIN the superconductor itself, which means an electric field. And you've spent how long now telling us all about how you can't have an electric field or a voltage in a superconductor? Your ideas are self-contradictory.

Yes, the fact that an extra voltage over a Josephson junction acts like a separate source input always amazed me

Perhaps because it's wrong.

 

[marplots]

I will admit that I can see your problem: You have never really thought about what an additional voltage V_J over a Josephson junction really implies. Without going into the details of how the circuit is changed to place an extra voltage V_J over the junction,...

After 18 pages, am I finally going to see the "where does the extra energy come from" question solved? Any chance that all the other stuff can be put aside and this additional voltage from another source added in will resolve the conservation of energy difficulties?

I'm not schooled enough to make a contribution, but I'd like to see my little herd of cats focus on this bit and see if agreement can be reached without too much dredging up of what someone said earlier.

18 pages. I deserve some closure here -- otherwise, I'll have to take my business to another lecture hall and leave all of you a poor student evaluation form at the Dean's office. The coup counting, while sometimes entertaining, is getting tiresome.

 

[ben m]

This is proved by the fact that when you increase the source voltage V_source from zero, the current increases without any voltage increase over the junction.

Nonsense. You're talking about the flat part of the I-V curve, right? Before the Josephson voltage becomes nonzero? There is no way to describe that as "an increase in the source voltage". That is an increase in the source current, with no change in the voltage anywhere. (Unless you want to talk about the innards of the Keithley or whatever you're calling a "source", but all you need to care about are the output terminals, which behave as I described. )

Also, for the fiftieth time: all of the discussion here has been about the higher-current situation, the one where V != 0 across the junction. That's the one we have drawn a diagram of, that's the one that emits photons. You keep forgetting about this and talking about the V = 0 case.

Now you place an additional voltage V_J to the source voltage V_source over the junction. This does not change the source voltage over the two contacts to the SIS (yes this is amazing but has been proved over and over again for a SIS system which allows Josephson tunneling as just described above) and can therefore only be accommodated if the voltage drops on both sides of the junction adjust in order order not to change V_source over the SIS.

Johan, your chapter 28 begins with a circuit diagram. That circuit diagram shows one and only one battery (and a resistor in series).

      A ---------------resistor----------battery---------- B

this question: what is the voltage difference between A and B? Is that what you call V_source, or V_j? Or V_s + V_j?

 

[Skwinty]

What puzzles me is that Johan has said on numerous occasions that the Josephson junction is irrelevant.

Yet here we are, discussing the Josephson junction again.