happyjack27 wrote:i wasn't talking about superconductors, just BECs proper. from what i understand of BCS its sort of like a BEC in that the cooper pairs are in a sense "entangled" and thus propagate em-fluctuations like a coherent wave.
No those are density waves which have been considered many years ago but rejected for many reasons.
i don't think we're talking about the same thing here. esp. given that you just agreed with me below.
that's really not my subject. i'm still learning quantumn mechanics.
The charge-carriers moving through a superconductor do not all have to move as they must for such a wave. Only enough of them move to transport the current. It is even possible to only send a single charge at a time through a superconductor. It is crazy to suggest that in such a case all the charge-carriers must move: However when more than one charge carriers must move they do so in a correlated fashion similar to, but not quite the same, as soldiers marching. But for this they do not have to be bosons or form a BEC.
that's what i said. though in my opinion i said it much clearer. certainly more concisely. i didn't say they move but simply that they propagate em forces coherently. that's a rather trivial statement and it doesn't require finite displacement. i never said they form a BEC in fact i said they do not. and it's pretty clear we're talking about electrons which obviously aren't bosons. so i really don't understand how you ended up misinterpreting me so much.
happyjack27 wrote:that's what i said. though in my opinion i said it much clearer. certainly more concisely. i didn't say they move but simply that they propagate em forces coherently. that's a rather trivial statement and it doesn't require finite displacement. i never said they form a BEC in fact i said they do not. and it's pretty clear we're talking about electrons which obviously aren't bosons. so i really don't understand how you ended up misinterpreting me so much.
I apologize if I misunderstood you. My problem is that I do not understand what you mean by: "they propagate em forces coherently". If we can sort out what you mean by em-forces within a superconductor we might be singing in the same choir.
happyjack27 wrote:that's what i said. though in my opinion i said it much clearer. certainly more concisely. i didn't say they move but simply that they propagate em forces coherently. that's a rather trivial statement and it doesn't require finite displacement. i never said they form a BEC in fact i said they do not. and it's pretty clear we're talking about electrons which obviously aren't bosons. so i really don't understand how you ended up misinterpreting me so much.
I apologize if I misunderstood you. My problem is that I do not understand what you mean by: "they propagate em forces coherently". If we can sort out what you mean by em-forces within a superconductor we might be singing in the same choir.
by "em-forces" i mean infinitesimal perturbations of the electromagnetic field. what did you think i meant? it's entirely unambiguous; there is only one definition. by coherently i mean they don't scatter it; that it doesn't get entropicized (a word i just made up) (e.g. turned into heat).
i should repeat my disclaimer: this is really just a vague idea; when it comes to superconductors, i really don't have any idea what i'm talking about. i know how normal conductors work. and i've read some of the wikipedia article about bcs theory. but that's it. i don't have enough of a background in quantumn physics (yet) to have more than a superficial understanding.
ladajo wrote:So why are you arguing with an old well experienced career physicist?
If it is an attempt to learn, then ask to be taught, don't play Socrates.
i'm not arguing. remember my original comment:
the point of the BEC is that a superposition of waves add together to form a single wave with the same form of the original waves. i don't think it's a misconception, i just think it's a different wording of what you said. that the superposing of the individual waves into one is a mathematical description of the time-evolution from a non-BEC to a BEC. yes, once it's fully bec the "original" waves are indistinguishable and can no longer be separated out, but that's the whole point of a BEC, isn't it?
i was just clarifying what someone said that seemed to be misinterpreted. and i wasnt even talking about superconductors, that is all BEC. you then dragged me reluctantly into superconductors.
also, if i wanted to learn something i'd get a book or watch a video lecture or something. i wouldn't ask someone whose credentials i don't even know a bunch of random questions. no offense.
Would the analogy of a Newton's cradle help here? Maybe the current 'impulse' pings through the stationary orbitals and flicks the tail-end charlie off the far side to continue the current?
(The last orbital refills thermally.)
Grurgle-the-Grey wrote:Would the analogy of a Newton's cradle help here? Maybe the current 'impulse' pings through the stationary orbitals and flicks the tail-end charlie off the far side to continue the current?
(The last orbital refills thermally.)
It is analogous but not the same: There is no momentum transfer through an array of superonducting orbitals since the energy to move and replace the other orbital is borrowed from the wave's inner energy resources outside three-dimensional space; The QFT theorists will call it "vacuum energy" but it is not a good term. For an orbital to do the required work to move to the position of the next orbital it "borrows" the required energy (delta)E, which according to wave mechanics can only be done for a time interval (delta)t. After having moved to the nect position, this energy is given back to the source as if the work that it has performed has been totally restored to energy, This happens cyclicly all along the array. It does thus not violate the second Law of Thermodynamics when a perpetual current flows around a ring since no entropy is generated during this movement.
Interesting but not really surprising: Superconduction occurs when the distances between the orbitals are less than a critical value as determined by the binding energy of the orbitals.
Thus you can have an array of orbitals for which the distance between adjacent orbitals are too large and when you smack them with a laser beam, the pressure can push them together. Alternatively, the orbitals can be excited into higher energy states for which the binding energy is less. The mechanism is really very, very simple indeed.
Interesting but not really surprising: Superconduction occurs when the distances between the orbitals are less than a critical value as determined by the binding energy of the orbitals.
Thus you can have an array of orbitals for which the distance between adjacent orbitals are too large and when you smack them with a laser beam, the pressure can push them together. Alternatively, the orbitals can be excited into higher energy states for which the binding energy is less. The mechanism is really very, very simple indeed.
I was about to post the link but giorgio beat me to it.
In any case I thought of both explanations and find the first one unsatisfactory (not that i am qualified but still :p). I presume is the latter, the binding energy.
Reason being, the laser beam is unlikely to make all the sites vibrate at the same time and simultaneously make a path all over the superconductor where all the distances are small enough at the same time. Your model requires that there is path that satisfies heissenberg energy-time relationship, not just satisfying it locally. Is that correct or did I misunderstand that part?
Raising the energy for a single electron, on the other hand, would be enough to satisfy delta(E)*delta(t)=g*h_bar at that particular site and when the electron/orbital jumps, the condition would still be satisfied at the destination point and so on. You cannot reduce distances but you can reduce energy requirements for the electron to break free by exciting the electron with the laser.
nogo wrote:
I was about to post the link but giorgio beat me to it.
In any case I thought of both explanations and find the first one unsatisfactory (not that i am qualified but still :p). I presume is the latter, the binding energy.
Reason being, the laser beam is unlikely to make all the sites vibrate at the same time and simultaneously make a path all over the superconductor where all the distances are small enough at the same time. Your model requires that there is path that satisfies heissenberg energy-time relationship, not just satisfying it locally. Is that correct or did I misunderstand that part?
Raising the energy for a single electron, on the other hand, would be enough to satisfy delta(E)*delta(t)=g*h_bar at that particular site and when the electron jumps, the condition would still be satisfied at the destination point and so on. You cannot reduce distances but you can reduce energy requirements for the electron to break free by exciting the electron with the laser.
Am I missing something?
No you are not missing anything and I can understand that you prefer the second explanation more when using laser excitation. The point I want to make is that I have found that when you generate superconduction or increase the critical temperature by changing the boundary conditions, the observed effect can be explained by either a change in the binding-energy, or inter-neighbor distances or both. What is interesting is that if you can decrease the distances by for example applying pressure, or increasing the orbital density by increasing doping, you can reach a point where the Coloumb interactions between the orbitals decreases their binding energy.
Since you obtain the highest critical temperature for the highest binding energy, one the usually finds that the critical temperature at first increases, and then at a high density of orbitals starts to decrease. There are lots of data on the ceramics that show this effect. For example when increasing the oxygen doping in YBCO, the critical temperature increases until at very high doping it starts to go down. The same has been observed for other ceramic superconductors when applying pressure: The critical temperature at first increases, goes through a maximum and then decreases.
Interesting but not really surprising: Superconduction occurs when the distances between the orbitals are less than a critical value as determined by the binding energy of the orbitals.
Thus you can have an array of orbitals for which the distance between adjacent orbitals are too large and when you smack them with a laser beam, the pressure can push them together. Alternatively, the orbitals can be excited into higher energy states for which the binding energy is less. The mechanism is really very, very simple indeed.
Yes, my "interesting" was referred exactly to this.
Indirectly this can support your point.
Giorgio wrote:Yes, my "interesting" was referred exactly to this.
Indirectly this can support your point.
Yes you are correct. I have far more results on superconductors where I accurately calculated their behavior when it cannot be explained by the main stream physicists.
All these manuscripts were rejected out-of-hand, since as Doug Scalapino wrote to me he is sure that it will one day be explained in terms of BCS theory; Or like a referee at Proc. Roy. Soc. wrote me: I am not an expert but will be surprised if (the main stream models) cannot explain it. Not an "expert" but "expert" enough to referee a paper for the Royal Society?!!
Betruger wrote:If I still live on campus this semester, I could help, provided clear references to look for. I don't have access to all journals, and this isn't my field at all, but I'd be glad to give you whatever I found.
I'll know whether I move off campus or not in a week or so.
This is an extremely kind offer. I do not even know for what to look. Maybe Grurgle-The-Gray can contact you?
Alright, I should be all set. I have access not to all, but to a good proportion of existing journals. Either of you can fire away with references, I'm at your disposal.
I'm almost certain to move off campus come May, so it's now or never, so to speak, for this. That said, I imagine I'm not the only one here who could do this for you guys.