Superconductivity at room temperature??

[johanfprins]

It doesn't. You have completely misunderstood ben. Fermi exclusion helps create Fermi energy level differences even in the absence of an electric field. An electric field is necessary to equalize Fermi energies for metals with different work functions.

So what? If there is a difference in Fermi-energy at two contacts there MUST be a NET electric field between the two contacts because there is an electric potential energy difference between the two contacts. If the Fermi-levels are the same at the two contacts, there is no electric-potential difference between the two contacts an therefore there cannot be a net electric-field between the two contacts. NOT one of your arguments can or will change this.

 

[ben m]

Are you really so stupid? There is NOTHING in this reference that does not agree with what I have been stating. Similarly in your references above. Instead of quoting wikipedia, why do you not try and think for yourself? Ah, I should not have asked the impossible from you.

Quite the opposite---I figured out this phenomenon on my own (it's pretty obvious, I'm sorry to say) because, as I've said, vacuum electronics and work functions are an important aspect of my research. I had been dealing with it for years before a colleague pointed out that "Volta potential" is the old electrochemistry term for the same thing.

Perhaps you did not understand the Wiki article. When two metals are in contact, their Fermi levels are the same. Your habit of saying "the Fermi level can only be changed by an electric field" suggests a prediction that the electrostatic potentials are also the same. But they're not.

How does the Pauli exclusion principle cause an electric field to be zero between two contacts at which the Fermi-level has the same energy? Or does it cause in some miraculous manner that there is an electric field between the two contacts when the Fermi-level has the same energy at the two contacts?

The Fermi level is the total energy resulting from the sum of two things. There is a binding energy, determined by quantum mechanics including things like Pauli exclusion and kinetic energy, call it B. There is also a contribution from electrostatic potential energy, call it U. JUST ADD THEM UP, there's nothing magical about it. The sum, E=B+U, can work out in various ways, depending on the device and its connections.

You can have, FOR EXAMPLE, a gold-sodium contact. B = -5 eV in gold and B=-3 eV in sodium. With the gold at U=0 (ground) and the sodium at U = -2 volts (electrostatic potential difference), you would have in the gold E = B + U = -5 and, in the sodium, E = -5 = B + U = -3 + -2 = -5. In other words, the Fermi level is constant across the two materials AND there is an electric field between them.

 

[johanfprins]

Sounds good. Anybody reading can check up on this on say wiki. I see ben has raised a point of objection, I'll look more closely at that. Maybe it will be related to no electric field outside a solenoid in the Aharonov-Bohm effect.

It's all reasonable semiconductor stuff. I looked a few things up on wiki and can't see anything wrong with it.

Thanks: If you find anything suspicious with statements 3 and/or 4, please return, so that I can address it: However, I doubt that you will since it is standard text book stuff which electronic engineers use every day.

Statement 5: It is an experimental fact that one can modify the surface of a diamond substrate to have negative electron affinity (NEA): This means that without charge-carriers within the conduction band, the conduction band is at a higher energy than the vacuum energy is outside the diamond. By injecting an electron (oops one cannot inject an electron but only a negatively charged wave-packet) into the conduction band near such a surface (using photo excitation for example), the charge-carrier will be at a higher energy than it will be outside the surface in the vacuum. Such an charge-carrier must thus flow out of the diamond into the vacuum where it will be an electron at a lower energy.

 

[ben m]

So what? If there is a difference in Fermi-energy at two contacts there MUST be a NET electric field between the two contacts because there is an electric potential energy difference between the two contacts.

No, you're wrong. The Fermi energy is not just the electric potential energy. Look it up.

Watch your terminology: "electric potential energy" is ill-defined.

Perhaps electrical engineers are taught to ignore contact potentials, because they think they "always cancel out" in circuit analysis. If you ignore contact potentials, then yes, "voltage" and "electrostatic potential" would be exactly the same thing. But this is obviously an oversimplification, as any thermocouple-junction builder will tell you. Is this the simplification that led you to reject mainstream physics, Johan?

 

[johanfprins]

Perhaps electrical engineers are taught to ignore contact potentials, because they think they "always cancel out" in circuit analysis.

You are deluded!! Solid State Electronics is based on contact potentials: So HOW THE HELL can an electronics engineer "ignore them". This is specifically what no electronics engineer ignores; and what I am also not ignoring:

You are ignoring the fact that there is a contact potential which requires the formation of a dipole layer across the interface; and that if there are enough charges that can flow through the interface, the resultant dipole CANCELS THIS CONTACT POTENTIAL Obviously if there are not enough charges, a dipole layer cannot form that is strong enough to cancel the contact potential. But this is not the situation that is being discussed.

If you ignore contact potentials, then yes, "voltage" and "electrostatic potential" would be exactly the same thing.

Where have I ignored contact potentials? YOU are the one who is ignoring them!!! You and Ziggurat are wasting my valuable time!!

 

[Farsight]

...Going back to Sol's wave function for a particle in a box....

Sol totally missed the point of the standing wave. He described what is in essence a standing wave in a box that's moving inside another box. Not a standing wave in a box. I tried to make this clear to him here and here but he said I have no idea what you're talking about. I can't make it any simpler. It's the electron itself that's the standing wave in a box. Please bear this in mind when you refer to multiple electrons in a box and say standard quantum mechanics tells us that the energy difference is kinetic energy.

Farsight, I have no issue with discussions of philosophy of science and attitudes toward "dogma". But Sol, Zig, ben m, et al are supplying experimental and mathematical evidence to support what the textbook is saying. That is not dogma - that is evidence. A valid response must provide the same level of evidence.

Yep. And I must say the quality of posts looks a whole lot better than it did. Let's hope everybody can maintain that standard and stick with the physics whilst avoiding insults.

I think Zig's comment says it quite well. Why can QM make testable predictions that pass experimentally if they are wrong?

They aren't wrong. I think the problem is with the Copenhagen interpretation, which is in conflict with solid state physics. It's that old civil war between theoretical and experimental physicist again. It bubbles up everywhere. One side thinks the other guys are erudite airheads, the other side thinks the other guys are a bunch of grease monkeys.

 

[Ziggurat]

So what? If there is a difference in Fermi-energy at two contacts there MUST be a NET electric field between the two contacts because there is an electric potential energy difference between the two contacts.

No, johan. You're wrong. That is precisely why the particle-in-a-box problem is relevant here: the Fermi energy is NOT determined solely by the voltage. Two materials with the SAME voltage (and thus no electric field between them) can have different Fermi levels. Why? because the energy of a quantum state, even a stationary quantum state, isn't simply the potential energy. It's also got another component, which standard quantum mechanics calls kinetic energy, which is different for different electrons in the same location.

 

[ben m]

You are ignoring the fact that there is a contact potential which requires the formation of a dipole layer across the interface; and that if there are enough charges that can flow through the interface, the resultant dipole CANCELS THIS CONTACT POTENTIAL

The dipole doesn't "cancel the contact potential". With two metals in contact, I can measure an electrostatic potential difference between them, i.e. in the form of an electric field; this is called the contact potential or the Volta potential. It hasn't been "cancelled" at all. It's still there and registering on my electrometer.

Yet the Fermi levels of the two metals are equal---they're in contact and have plenty of mobile charge carriers.

This is a case where the electrostatic potential difference is not zero, and the Fermi level difference is zero. What does this tell you, Johan? Does it the Fermi level is, or is not, the same thing as the electrostatic potential?

 

[excaza]

You and Ziggurat are wasting my valuable time!!

You're arguing with anonymous people on an internet forum. Your time can't be that valuable.

 

[ben m]

Sol totally missed the point of the standing wave. He described what is in essence a standing wave in a box that's moving inside another box. Not a standing wave in a box. I tried to make this clear to him here and here but he said I have no idea what you're talking about. I can't make it any simpler. It's the electron itself that's the standing wave in a box. Please bear this in mind when you refer to multiple electrons in a box and say standard quantum mechanics tells us that the energy difference is kinetic energy.

No, Farsight, you are misunderstanding. Perhaps you're trying to make the leap to an equivalence-principle statement, "All types of energy are the same when it comes to inertial mass and gravity", but that's not appropriate here. Sol was perfectly right---an electron in a box, whether it's a standing wave or a traveling one or a mixture of the two, has a sensibly-defined kinetic energy.

They aren't wrong. I think the problem is with the Copenhagen interpretation, which is in conflict with solid state physics.

a) Nothing discussed here has gone anywhere near questions of interpretation. We're talking about simple eigenstates and expectation values, not "what really happens during measurements?"

b) There is no conflict whatsoever between quantum mechanics and solid state physics. Where did you get that idea?

It's that old civil war between theoretical and experimental physicist again. It bubbles up everywhere. One side thinks the other guys are erudite airheads, the other side thinks the other guys are a bunch of grease monkeys.

c) What the heck!? Theorists and experimentalists have no disagreement whatsoever on the validity of the Schrodinger equation and of all of the topics being discussed here. Interpretational issues, like Copenhagen vs. many-worlds, etc., are not split along theory-experiment divide. In fact, solid state physics (and foundational quantum mechanics) are a model for happy and fruitful theory-experiment collaboration.

 

[Ziggurat]

Sol totally missed the point of the standing wave. He described what is in essence a standing wave in a box that's moving inside another box. Not a standing wave in a box. I tried to make this clear to him here and here but he said I have no idea what you're talking about. I can't make it any simpler. It's the electron itself that's the standing wave in a box. Please bear this in mind when you refer to multiple electrons in a box and say standard quantum mechanics tells us that the energy difference is kinetic energy.

Sol knows exactly what he's talking about. And your meaning is not at all clear. It sounds like you're talking about the idea of electrons being photons in a box, but I can't tell for sure, nor is it relevant. Sol's wave function is the standard solution to ANY massive particle confined to a square well. That state has kinetic energy, although johan denies this. THAT is the point of the standing wave solution, a point which johan cannot grasp. I can't tell whether or not you understand that such a solution has kinetic energy, but you seem to be focusing on something completely different than what was being discussed here.

They aren't wrong. I think the problem is with the Copenhagen interpretation, which is in conflict with solid state physics.

johan doesn't accept the Copenhagen interpretation of quantum mechanics, but he doesn't accept pretty much anything else about quantum mechanics either. Regardless of Copenhagen, do you accept that calculated expectation values still accurately predict the average of a measurement? Do you think that one can calculate the kinetic energy of a state as <p²>/2m? If so, then you're in agreement with standard quantum mechanics, and in disagreement with johan. If not, then your disagreement with quantum mechanics extends FAR beyond the Copenhagen interpretation, and quantum mechanics becomes basically irreconcilable with such an opinion.

It's that old civil war between theoretical and experimental physicist again.

No, it really isn't. This has nothing to do with theory vs. experiment. This has everything to do with johan's vision of physics (which is internally inconsistent, BTW) vs. standard textbook physics (both experimental AND theoretical).

 

[ben m]

No, johan. You're wrong. That is precisely why the particle-in-a-box problem is relevant here: the Fermi energy is NOT determined solely by the voltage. Two materials with the SAME voltage (and thus no electric field between them) can have different Fermi levels.

Ziggurat, just FYI, I've been carefully avoiding the word "voltage", which (in circuit analysis, i.e. of the sort that ignores contact potentials) might legitimately be taken to be synonymous with the Fermi level. I've been calling it "electrostatic potential" (as in U = integral E dx) to exclude any chance of this ambiguity.

(I don't think this is Johan's actual problem, or at least not his main one, but still.)

 

[Vorpal]

Sol totally missed the point of the standing wave. He described what is in essence a standing wave in a box that's moving inside another box. Not a standing wave in a box. I tried to make this clear to him here and here but he said I have no idea what you're talking about. I can't make it any simpler. It's the electron itself that's the standing wave in a box. Please bear this in mind when you refer to multiple electrons in a box and say standard quantum mechanics tells us that the energy difference is kinetic energy.

The t'Hooft et al article does not support anything Johan posited. In their own words, "no new results will be derived." And reading it, there indeed isn't any deviation from standard textbook-standard physics in any of the conclusions, which are pretty trivial to boot. So if you believe them, it is entirely appropriate to apply standard QM to the question... which Johan also asked to do previously.

It absolutely does contradict either Sol or Ziggurat in any way. It's mostly irrelevant, and the the small parts that are relevant actually confirm their positions. When you say things like:

"Trap a massless photon in a box and its momentum now appears as inertia."

You're apparently forgetting certain qualifiers, the most relevant of which being "inertia of the box system." Which... makes it irrelevant to the question discussed here.

 

[johanfprins]

No, johan. You're wrong. That is precisely why the particle-in-a-box problem is relevant here: the Fermi energy is NOT determined solely by the voltage. Two materials with the SAME voltage (and thus no electric field between them) can have different Fermi levels.

What do you mean by "the same voltage"? Two materials in contact? two separate materials contacted in parrallel between the same potential and the ground? You obviously cannot even define what you want to talk about! Voltage is a DIFFERENCE IN ENERGY. How can two materials have the same voltage? I am really getting tired of your nonsensical posts.

Obviously, the same wave-function can have different energies within two different metals at the same potential: But this has NOTHING to do with kinetic energy; only with the workfunctions (and thus average background potential of the electrons) of the two materials.

 

[johanfprins]

You're arguing with anonymous people on an internet forum. Your time can't be that valuable.

You have a good point! I would raher like to argue with honest people who are not scoundrels hiding behind anonymity but are willing to post their CV's. But it seems that the world has become so corrupt that there are not enough of such people around anymore. Thank God for Farsight who came on line. Although my time is valuable, I have to fight on in the best interest of the future of physics.

 

[Ziggurat]

What do you mean by "the same voltage"?

I mean zero voltage difference. If you measure the path integral of the electric field between them, it will be zero.

Two materials in contact?

Not necessarily.

You obviously cannot even define what you want to talk about! Voltage is a DIFFERENCE IN ENERGY.

No it isn't. Voltage is electric potential. It's the path integral of your electric field between one location and whatever reference point you want to pick. Really, this is intro textbook stuff, and you can't even get a basic definition right?

Voltage is NOT energy. It never has been. The potential energy of a charge due to electric fields is proportional to voltage, and that's the important property for my argument, but it's not actually the same thing as potential energy. And potential energy is quite definitely not the same thing as total energy either, a point which you have yet to come to grips with but which is fundamental to your current misconception.

Obviously, the same wave-function can have different energies within two different metals at the same potential: But this has NOTHING to do with kinetic energy; only with the workfunctions (and thus average background potential of the electrons) of the two materials.

Where does this magic work function come from? Because it doesn't come from differences in the potential energy of electrons in two materials at the same voltage.

Nor did you answer my question about different wave functions in the same box. They've got the same potential (obviously), they're both standing waves, and yet they don't have the same energy. What do you want to call that energy difference, johan? Standard quantum mechanics says it's due to kinetic energy. What label would you have us choose? Or do you deny that there IS an energy difference for different values of n in Sol's standing wave?

 

[johanfprins]

The dipole doesn't "cancel the contact potential". With two metals in contact, I can measure an electrostatic potential difference between them, i.e. in the form of an electric field; this is called the contact potential or the Volta potential. It hasn't been "cancelled" at all. It's still there and registering on my electrometer.

Of course you can, since you now have a situation where you disturb the cancellation of the contact potential, or do you really think you can measure a potential without a TINY current flowing through a voltmeter? You really have a problem you know.

Yet the Fermi levels of the two metals are equal---they're in contact and have plenty of mobile charge carriers.

Correct, but you just do not know enough physics to understand what you are doing when you measure with a thermocouple. Do the whole circuit analysis, which I am sure you are incapable of doing.

This is a case where the electrostatic potential difference is not zero, and the Fermi level difference is zero. What does this tell you, Johan? Does it the Fermi level is, or is not, the same thing as the electrostatic potential?

If you have any intelligence you will be able to analyse the circuit with and without the voltmeter. I know that you are not capable of doing this on your own. But ask a first year student to help you PLEASE!!!!!

It is late: So goodbye for now!

 

[ben m]

Of course you can, since you now have a situation where you disturb the cancellation of the contact potential, or do you really think you can measure a potential without a TINY current flowing through a voltmeter? You really have a problem you know.

Are you saying that the Volta potential is a measurement artifact?

Seriously, Johan: it's one thing to say "I have a theory which I think is better than Schrodinger's theory". It's quite another thing to say "everyone who doesn't agree with me is an unschooled moron". But you've gone the next step: you are now insulting me for citing an experiment fact, which you (first) presumed I was making up and (now) are guessing is a measurement artifact.

Johan, it's true that I think that your experiments did not prove what you thought they proved, but remember that I read about the experimental setup before saying so. You're rejecting the Volta potential data knowing nothing about it except that it contradicts you.

(And, by the way, the volta potential is NOT a measurement artifact; it results in an ordinary, Maxwell-obeying electric field that can be measured in free space outside the metal. Practical tools include Kelvin probes, cold atoms, photoemission spectroscopy, and various scanning probe techniques.)

 

[Reality Check]

Voltage is a DIFFERENCE IN ENERGY.

That is wrong: Voltage is a DIFFERENCE IN ELECTRICAL POTENTIAL.
This is easily seen by looking at the units of measurement. Voltage does not have the units of energy, e.g. Joules.

 

[Farsight]

No, Farsight, you are misunderstanding. Perhaps you're trying to make the leap to an equivalence-principle statement, "All types of energy are the same when it comes to inertial mass and gravity", but that's not appropriate here.

I'm not misunderstanding this, or trying to leap to an equivalence-principle statement.

Sol was perfectly right---an electron in a box, whether it's a standing wave or a traveling one or a mixture of the two, has a sensibly-defined kinetic energy.

And he totally missed the point. See page 61 where Johan said To have kinetic energy a light wave must move relative to an inertial refrence frame. When it is within the cavity, it forms a standing wave because the boundaries of the cavity do not allow the light wave to leave the cavity. Thus the wave is not moving relative to the inertial reference frame of the cavity. Thus it now has no kinetic energy within this reference frame at all. Its energy is all stationary energy... The standing wave of light equates to the electron. The electron-in-a-box equates to a light wave in a box, in another box. And there's Zig saying Sol's wave function is the standard solution to ANY massive particle confined to a square well. That state has kinetic energy, although johan denies this.. Johan was talking about a light wave, not a massive particle. I'm afraid you're all getting this wrong, making a meal of it, and digging a hole for yourselves.

a) Nothing discussed here has gone anywhere near questions of interpretation. We're talking about simple eigenstates and expectation values, not "what really happens during measurements?"

I beg to differ. I'm seeing sentences like this whole argument contradicts standard quantum mechanics in response to simple statements associated with relativity. A radiating body loses mass.

b) There is no conflict whatsoever between quantum mechanics and solid state physics. Where did you get that idea?

From a senior condensed matter physicist who told me that he and his colleagues took a "realist" view that was in total conflict with the Copenhagen Interpretation of quantum mechanics. And from other people in the related spheres of optics and electronics.

c) What the heck!? Theorists and experimentalists have no disagreement whatsoever on the validity of the Schrodinger equation and of all of the topics being discussed here. Interpretational issues, like Copenhagen vs. many-worlds, etc., are not split along theory-experiment divide. In fact, solid state physics (and foundational quantum mechanics) are a model for happy and fruitful theory-experiment collaboration.

Oh come on ben. Theorists and experimentalist have a long history of Who ordered that? rivalry. But let's not dwell on that or our different opinions as illustrated above, let's just stick to the hard facts of the physics.