A description of superconductivity - in a little more detail than you need at A Level - to explain the basic concepts of a quantum mechnical phenomenon.
Thank you for posting this, really appreciate it. Good job putting this together even if people nitpick errors. Everyone knows to be well informed cross ref multiple sources esp online. Anyway thanks again!
How does adding the superconductor avoid the problem of instability? Ordinary magnets will repel but fly away. No matter how you arrange the magnets or how many you have, there is no point of stability in the system. I don't understand how superconductors solve this problem. Help?
TY. i tried listening to the 1st Stanford University lecture on superconductivity & i learnt more in 12 minutes of this video than i did in an hour of that 1 That video talks about the Meissner effect but just says magnetic fields are excluded from a superconductor That video doesn't say: 1) Ordinarily if you have a metal & a magnetic field, the magnetic field will pass straight through the metal 2) Why they're excluded from a SC (DrPhysicsA says little surface currents in the SC create a magnetic field) 3) That the Meissner effect can cause levitation of a magnet
Thanks. I assume you mean the graph at 2:21. Others have commented on this. For some reason (which I cant now remember or justify I drew the temperature scale decreasing to the right (instead of the normal increasing). I have inserted an annotation to make that clear.
Thank you for posting this, you have managed to break down the fundamental concepts of this topic quite well. One thing worth noting in your explanation of the Meissner effect-- I believe the youtube videos you are referencing all use Type II superconductors (ceramics, mostly YBCO from the looks of it) rather than Type I (metals). As far as I am aware liquid N2 is not capable of causing any pure metals to reach their T_c and stimulate magnetic expulsion.
hey there. bit of a weird question but i am doing a similar piece of cw and was wondering if it was possible to send me yours to have something to compare to? thanks but no probs if not. 😃
Good video. Would be nice to have another one explaining how it is that Cooper Pairs flow through the metal unhindered (if there has not been one - video of this type - added already).
These are good fundamental questions. We can offer an explanation as to why charges repel or attract (both of which involve exchange bosons (photons). But as to why that makes them attract/repel or how each knows the other is there is still a mystery.
Magnetic field exclusion is superconducitvity because without a mix of many particle sizes, which is what cold or positive ion charge creates, there is extremely little or no progressive kinetic reactions beyond the 2 extreme particles of mass vs energy. A surface tension exists which allows a perfect matrix of 7 to 9 of the largest particles to group on linear planes which disallow linear DeBroglie orbits, forcing all energy to travel though that form of concentrated mass particles.
I assume you mean the graph at 2:13. The temperature axis decreases as you move to the right. I hope I make that clear in the commentary, but I have added a footnote.
Excellent,Sir,In the vidio you talk of a dish holding the fluid.I haVe seen a like experiment with the use of liquid helium.so why does not this superfluid seep through the dish?
Why does exemption from the Pauli Exclusion Principle allow the Cooper pairs (bosons) to flow with zero resistance? Why are they superfluid? Do they avoid collision with metal nuclei because of the vibration of the lattice as they pass by?
Could I ask, in regards to 'Cooper pairs forming by the exchange of phonons", is that distortion in the lattice which attracts an electron (due to the temporary positive region it creates) the point in which this exchange of phonons occurs? And this exchange of phonons is occuring b/w the lattice and the Electrons?
Can you please help with a question? I've always been under the impression that from a battery electrons from very slowly (a few mm per second) at "drift velocity" from the negative battery terminal to the positive. But the current that we call electricity flows near the speed of light from the positive terminal to the negative. I assume this is a positively charged current. So with a superconductor will current and electrons from in the same direction? Will they flow at the speed of light? What implications are there from using positive charges to negative? And finally is this only good for transmission of power over long distance to charge a battery or capacitor? Because won't the current eventually stop when it hits its first resistors such as a light bulb or whatever you are intending to power?
The point is that at very low temperatures the electrons encounter no resistance. Once you introduce any systems which have resistance then the condition no longer applies.
6:25 I understood everything until this part. The electrons give rise to deformations in the lattice, which creates a larger positive charge that attracts more electrons. I don't understand this part: due to a tension between the electrostatic repulsion between the electrons, and the electrons' electrostatic attraction towards the positive charge, they form Cooper Pairs. what is the logic behind this, why do the electrons have to form pairs? why can't there be cooper triplets? and how does this 'solve the tension' between the two conflicting electrostatic forces of attraction/repulsion - whats the point of pairs? And then at 9:21 - why do Cooper pairs experience no resistance - how is resistance related to the Pauli exclusion principle?
Its actually more complicated than just defining paired electrons of an atom is diamagnetic ,while unpaired electrons are parramagnetic(the paired are mirrored) while ferro are fully aligned ...further research(personal) shows that every atom are magnetized in a different order depending on the number of protons in an atom ,so its like cutting a one inch magnet a million times you'll still have millions of magnet. The negative terminal of an electron is discharge field which then accelerates back to counterspace (mass) charge at the center of the atom in which case the neutrons being dielectric(dielectric terminates into counterspace ,which also drives magnetism) capacitance and the protons are the fly wheel of dielectric charge(positive terminal) as it torques back out(CW to CCW) at the other side. if there's any more questions i have an article for you if your interested thanks.
@@demoncore7275 _"The negative terminal of an electron is discharge field which then accelerates back to counterspace (mass) charge at the center of the atom in which case the neutrons being dielectric(dielectric terminates into counterspace ,which also drives magnetism) capacitance and the protons are the fly wheel of dielectric charge(positive terminal) as it torques back out(CW to CCW) at the other side"_ are you just talking random gibberish?
@@CaptainWrinkleBrain _"An electron in a metal normally behaves as a free particle. The electron is repelled from other electrons due to their negative charge, but it also attracts the positive ions that make up the rigid lattice of the metal. This attraction distorts the ion lattice, moving the ions slightly toward the electron, increasing the positive charge density of the lattice in the vicinity. This positive charge can attract other electrons. At long distances this attraction between electrons due to the displaced ions can overcome the electrons' repulsion due to their negative charge, and cause them to pair up. The rigorous quantum mechanical explanation shows that the effect is due to electron-phonon interactions."_ ok but you're not answering the questions: why pairs & not triplets? Why do the pairs experience 0 resistance?
@H T your questions are very good. Perhaps this is what's happening: 1) The 2 electrons forms a single object (known as a singlet) 2) the 2 electrons are very far apart. 3) Electrons are waves so we can regard the Cooper pair as a very long wave. 4) Because the waves are so long there's a lot of overlap with other Cooper pair waves 5) The 2 electrons have opposite spin which means the singlet has zero spin in total 6) Things which have zero spin are bosons 7) Bosons don't have to obey Pauli's exclusion principle which says "2 electrons in the same atom cannot have an identical set of values for the 4 quantum numbers n, l, m, ms" 8) As the electrons are cooled they all fall into the lowest possible energy state with the same 4 quantum numbers. 9) We're talking millions of electron-pair waves. They overlap & strengthen each other like bricks in a wall 10) Since this wall is composed of so many electrons it's solid as fuck. 11) If the electrons formed a triplet the spins wouldn't cancel out = not a boson = not a wall 12) Normally electrons travelling through a wire experience resistance because the atoms in the wire are jiggling & getting in the way of the electrons 13) But here, the atoms in the copper wire aren't jiggling very much cause it's so fing cold. They just don't have the energy to push the solid mass of electrons around 14) Thus there's no resistance
Thanks for the video....I have a little question ..can the potentail difference across the battery cause the production of an electric field when then cause the electrons to move around ?
Is it possible that we're in a sea of dark matter that's everywhere within our expanding universe with the exceptions of not being beyond that edge (perhaps explaining the faster than light speed expansion), not being in the extreme density of black holes (possibly explaining the faster than light speed Hawking Radiation), and perhaps not being within superconductive fields either? Gravitational waves are dark matter density waves, no? Thx
Brilliant video. But how do the electron pairs becoming Bosons, stop them from physically colliding with the lattice structure or the positive copper atoms? And right at the last 5 seconds of the video, why do the magnetic poles exist only on the sides? Why not the centre?
One question. When the electrons combine into a Cooper pair, what about that change allows for zero resistance? The only change is that they become a composite boson, which means they now have a whole number spin. So is the spin responsible for their lack of reaction with protons?
Sounds like Cooper discovered a new type of composite particle, akin to baryons and mesons. Unlike baryons and mesons, which are made up of quarks, These cooper pairs are made with leptons. Any chance that this may apply to mu electrons or possibly neutrinos?
Wouldn't there be a net negative charge in the middle since the electrons will tend to travel on the outside and the lattice will be distorted towards the outside of the wire?
Brilliant tutorial! But electron pairs seem confusing to me as the nucleus still has electrons attached to it at the lower energy level and has a much much larger mass, so they use lower energy electrons as the mortar for the lattice, while squashing the higher energy electrons moment layer together - allowing higher energy electron to move thought he material , and act like a liquid. But if he material is cooled enough I still don't understand the following - 1) Why electron pairs form to produce a super liquid? (unless your saying electrons can get closer together because their not getting energised by heat) and 2) Ultimately why there is no magnetic field in centre of material and why both end of magnet are repelled? As there still magnetic field produced around each atom.
But you're missing one important item; The Meissner effect surface currents geometry. Egor Babaev made a model proving it as I predicted it using my physics theory in 1996, copyrighted 2002, a few years before his model was even made. 8 charge spins around 1 larger one will stack like 16 around 1 viewed from the top, and give charge a reason form concave and convex fields to and from the source current in order to balance all charge points at once against said field.
You show the magnetic field from the superconductor pointing North outwards, but it does not act like a magnet; it opposes both N and S; (hence diamagnetic?).
Also, electrons have a spin of 1/2 right? So when cooper pairs form, do the spins add or subtract to make 1 or 0? So they become a boson, with integral spin?
DrPhysicsA sir..u have told that according to meissner effect magnetic field cannot penetrate the metal,so i assume it cannot induce the current on the surface in this case..so,what is the source of the surface current on the metal that flows forever and ever??
Tanvir Kaisar no, its not like it cant pass...i think its that the induced current (eddy current) on the surface produces an equal amount of magnetic field opposite to the magnetic field. Then the flux just cancels out...since its a super conductor..the magnetic field doesnt die down because the current induced will go on forever....same thing happens with regular conductors, but after a while, the current induced by the change of magnetic flux dies down, which allows the magnetic field through it...
Yes, but not exclusively. To quote Wikipedia: "The name phonon comes from the Greek word φωνή (phonē), which translates as sound or voice because long-wavelength phonons give rise to sound. In physics, a phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter, such as solids and some liquids."
3D+Time is interpreted as 4 dimensions, but if everything is actually Time as mechanism of Quantum Fields and associated spatial-particles, then Superconduction of the type shown should be known as a 4D phenomenon of 2×2D prime planar Cooper pairs occupying the lattice of the conductor simultaneously in a specific example of the "One Electron theory" at or near Zero Kelvin, the Neutron resonance shell. (As a simplified guesstimate of probability behaviour)(?)
Why do like charges repel? I know they exchange photons but then how do opposite charges attract? Do they exchange photons backwards to come towards each other? How do they know the other one is there?
Right, Onnes, the discoverer of superconductivity, cooled mercury with liquid helium to achive a 4.2 kelvin temperature, the other metals have similar superconductivity points. The YBCO however achives superconductivity at a temperature that can be achieved with liquid nitrogen, this is known as high temperature superconductivity and it's much more affordable and easy than achieving superconductivity with a normal metal, so it's what the youtube videos use
I am currently doing AS physics and for my first piece of coursework I chose to look at superconductors. This video has been a fantastic help and thanks for that, but I would suggest that if you ever do another one you could include at least something on the structure of superconductors specifically and how the structure of them affects their Tc. Also, I personally found/find the use of copper in the example quite confusing, as I didn't think it was a superconductor? Thanks.
Thank you for your kind comments. Upon reflection it probably was not a good idea to use copper as an example since as you say it is not actually a superconductor. As you probably realise, my videos are designed to give a basic introduction to the subject so that someone can then go on to look at the more advanced explanations elsewhere so it's a balance of keeping it simple without being too misleading. I've added an annotation to explain about copper.
DrPhysicsA You are right, and this is a fantastic video to get a basic understanding. I now know that the Tc is related to the mass of the ions in the material, so perhaps another annotation could point that out? Thanks for getting to back to me, I find your videos very informative and I have subscribed :)
DrPhysicsA Good, Good, Also you might wanna add that "Cooper pairs" theory can't explain how does Type 2 Superconductor work... Since you mentioned energy limit for Cooper pair forming is 10^-3 eV , where as Type 2 SCON operates @ 50K-168K..
One last question - is Superconductivity only relevant for DC. It would seem once you take away the AC Voltage, (the pump pulling and pushing) you end of with DC only.
so a cooper pair of electrons is not with an electrical character at all but they transform to something else... how much is the speed of "electrons" passing through a superconductor?
Hi.. Why meissner effect shows itself in other way/in reverse way? I mean why repels? Why we cannot see attraction. Why the surface current cannot be the in reverse direction? Thanks a lot
Hi, I am assuming that the Cooper pairs need kinetic energy to propagate through the conductor. So if the temperature is decreased to 0K, thus there is no kinetic energy in the system, will the Cooper pairs still propagate and will the conductor still be a super conductor? Thanks in advance.
+Ruart Crous The temperature is in essence the average kinetic energy/ Just because the temperature of the copper is 0K does not mean particles cannot pass through it. Any particle passing through the temperature would only loose energy upon a collision. Which never happens. Its like saying as soon as anything enters space it stops moving. Rather it keeps going until a collision removes KE
I was leaning toward what Walter said! Except the whole colliding with atoms and the conservation of momentum confuses me! In the electron theory one can have an infinite length of wire when pulled the e- flow must be disrupted....etc...The point is that e- flow should never collide with nuclei causing vibrations B fields at the atomic level with the forces and all the wave particle duality...Massive uncertainty!
if the resistance of the bulb wire goes down shouldnt it glow less? i mean it glows because of heat right? less resistance means less heat and less glow?
Sara Chakir LOL guys, ASK yourselves what causes lamp to "glow".. luckily filament lamp is made of Wolfram not BSCCO. Else we would live in a dark world))))..
The Meisner effect stops working if you increase the strength of the Magnetic field. Then the critical temperature for the metal will decrease. That’s why you can only have a certain amount of current in a superconductive system before it stops working. If you increase the supply of current through the system, the magnetic field strength will increase and the system will experience resistance.
Can you please explain that how will electricity become never-ending? If that was the case, then people would attain superconductivity on a substance and then after passing a current and attaining unlimited energy they could run the plant and cool it forever and have free energy forever.
@@bonnielunel6014 no, it's wrong. As temperature DECREASES, resistance DECREASES. So as temp INCREASES, resistance INCREASES. If Temp is 0, resistance is also 0. This is clear from the formula for resistance, R = (pLT)/A. So the graph should start at 0,0 & increase along both axes.
@@codebulletin NO, it's wrong. As temperature DECREASES, resistance DECREASES. So as temp INCREASES, resistance INCREASES. If Temp is 0, resistance is also 0. This is clear from the formula for resistance, R = (pLT)/A. So the graph should start at 0,0 & increase along both axes.
Kani Kagami thats the finded thing with mecurcy that only at certain temperature directly come zero and behave as superconductivity no other metal come suddenly to zero
This is a brilliant explanation. Concise, yet informative. You have a gift. Thank you!
Oh man you're a life saver, found this 2 days before my Tests....
thanks and keep up the good work
at 2:40, you should draw the graph in the opposite direction, because the temperature is decreasing ?
You're correct. I thought the same thing lol
Maybe along + x-axis, the temperature was decreasing.
Thank you very much Doctor, I really appreciate what you are doin by helping many people like me. Great explanation by the way.
although this almost took me an hour from start to finish but I've never understood physics as clearly before, bravo!!!
thank you so much
Very interesting! Thanks! I understand more supraconductivity
Thank you very much for this video. This is exactly the kind of description of superconductivity I was looking for.
This is so well explained.
Great video!
Thank you for posting this, really appreciate it. Good job putting this together even if people nitpick errors. Everyone knows to be well informed cross ref multiple sources esp online. Anyway thanks again!
Awesome video, even when something made up a question, you answered it right away.
I really thank you, this will be a great help for my modern physics subject.
Thank you sir, for providing me a good explanation about superconductivity.
Excellent video! I learned a lot.
Excellent explanation, it's really a pleasure to be taught that way. Congratulations.
thanks a lot the best explanation ,i was finding for many days ,thanks a lot
I should've looked it up before commenting. it's wise not to doubt a physicist. Thanks for the uploads and the reply.
Amazing video mate, helped a lot, thanks!
Totally awesome video sir .........thanks a lot
Awesome video, great revision for my Physics exam!
How does adding the superconductor avoid the problem of instability? Ordinary magnets will repel but fly away. No matter how you arrange the magnets or how many you have, there is no point of stability in the system. I don't understand how superconductors solve this problem. Help?
It's been 9 years and no one replied. Did you get an answer?
Thank-you very much for the information's, well done Bravo!
TY. i tried listening to the 1st Stanford University lecture on superconductivity & i learnt more in 12 minutes of this video than i did in an hour of that 1
That video talks about the Meissner effect but just says magnetic fields are excluded from a superconductor
That video doesn't say:
1) Ordinarily if you have a metal & a magnetic field, the magnetic field will pass straight through the metal
2) Why they're excluded from a SC (DrPhysicsA says little surface currents in the SC create a magnetic field)
3) That the Meissner effect can cause levitation of a magnet
Dr. A level physics is always amazing
this is how educational videos should be made. I hate when people try to animate lessons.
Thanks. I assume you mean the graph at 2:21. Others have commented on this. For some reason (which I cant now remember or justify I drew the temperature scale decreasing to the right (instead of the normal increasing). I have inserted an annotation to make that clear.
This is absolutely amazing
O_O... i love you for doing every single one of these videos
Great video....its very helpfull.....
Thank you for posting this, you have managed to break down the fundamental concepts of this topic quite well. One thing worth noting in your explanation of the Meissner effect-- I believe the youtube videos you are referencing all use Type II superconductors (ceramics, mostly YBCO from the looks of it) rather than Type I (metals). As far as I am aware liquid N2 is not capable of causing any pure metals to reach their T_c and stimulate magnetic expulsion.
Simple and brilliant explanation
Doing this in my A2 research coursework, this video has been so helpful!!
hey there. bit of a weird question but i am doing a similar piece of cw and was wondering if it was possible to send me yours to have something to compare to? thanks but no probs if not. 😃
Starrymite yeah sure, dm me?
I think I sent a post with my email but not sure if you can see it
scrazza did you smash or nah?
Thank you! Super helpful!
Thank you, it was very interesting.
you are a lot better professor than I had at Devry
you're so amazing sir!
Its really nice.... exellent.....
amazing explanation sir!
Good video. Would be nice to have another one explaining how it is that Cooper Pairs flow through the metal unhindered (if there has not been one - video of this type - added already).
Thank you. You made a difficult thing easy to understand.
woww!!! great work sir!!
Very nice and concise.
The best explanation ever
sir u should make more videos ...they r always entertaining to enjoy even if u r from different field of work
These are good fundamental questions. We can offer an explanation as to why charges repel or attract (both of which involve exchange bosons (photons). But as to why that makes them attract/repel or how each knows the other is there is still a mystery.
Very interesting. I'll be sure to refer to this in the next year or so as I do my A-levels
SHJ Gaming A level physics online is better imo
Magnetic field exclusion is superconducitvity because without a mix of many particle sizes, which is what cold or positive ion charge creates, there is extremely little or no progressive kinetic reactions beyond the 2 extreme particles of mass vs energy. A surface tension exists which allows a perfect matrix of 7 to 9 of the largest particles to group on linear planes which disallow linear DeBroglie orbits, forcing all energy to travel though that form of concentrated mass particles.
I assume you mean the graph at 2:13. The temperature axis decreases as you move to the right. I hope I make that clear in the commentary, but I have added a footnote.
Excellent,Sir,In the vidio you talk of a dish holding the fluid.I haVe seen a like experiment with the use of liquid helium.so why does not this superfluid seep through the dish?
Why does exemption from the Pauli Exclusion Principle allow the Cooper pairs (bosons) to flow with zero resistance? Why are they superfluid? Do they avoid collision with metal nuclei because of the vibration of the lattice as they pass by?
Could I ask, in regards to 'Cooper pairs forming by the exchange of phonons", is that distortion in the lattice which attracts an electron (due to the temporary positive region it creates) the point in which this exchange of phonons occurs?
And this exchange of phonons is occuring b/w the lattice and the Electrons?
Can you please help with a question? I've always been under the impression that from a battery electrons from very slowly (a few mm per second) at "drift velocity" from the negative battery terminal to the positive. But the current that we call electricity flows near the speed of light from the positive terminal to the negative. I assume this is a positively charged current. So with a superconductor will current and electrons from in the same direction? Will they flow at the speed of light? What implications are there from using positive charges to negative? And finally is this only good for transmission of power over long distance to charge a battery or capacitor? Because won't the current eventually stop when it hits its first resistors such as a light bulb or whatever you are intending to power?
The point is that at very low temperatures the electrons encounter no resistance. Once you introduce any systems which have resistance then the condition no longer applies.
Super helpful! thanks mate.
Ghufran Aldawood if you think that was helpful you should check out a level physics online - that is such a helpful channel exlained very clearly
6:25 I understood everything until this part. The electrons give rise to deformations in the lattice, which creates a larger positive charge that attracts more electrons. I don't understand this part: due to a tension between the electrostatic repulsion between the electrons, and the electrons' electrostatic attraction towards the positive charge, they form Cooper Pairs. what is the logic behind this, why do the electrons have to form pairs? why can't there be cooper triplets? and how does this 'solve the tension' between the two conflicting electrostatic forces of attraction/repulsion - whats the point of pairs? And then at 9:21 - why do Cooper pairs experience no resistance - how is resistance related to the Pauli exclusion principle?
Its actually more complicated than just defining paired electrons of an atom is diamagnetic ,while unpaired electrons are parramagnetic(the paired are mirrored) while ferro are fully aligned ...further research(personal) shows that every atom are magnetized in a different order depending on the number of protons in an atom ,so its like cutting a one inch magnet a million times you'll still have millions of magnet. The negative terminal of an electron is discharge field which then accelerates back to counterspace (mass) charge at the center of the atom in which case the neutrons being dielectric(dielectric terminates into counterspace ,which also drives magnetism) capacitance and the protons are the fly wheel of dielectric charge(positive terminal) as it torques back out(CW to CCW) at the other side. if there's any more questions i have an article for you if your interested thanks.
@@demoncore7275 _"The negative terminal of an electron is discharge field which then accelerates back to counterspace (mass) charge at the center of the atom in which case the neutrons being dielectric(dielectric terminates into counterspace ,which also drives magnetism) capacitance and the protons are the fly wheel of dielectric charge(positive terminal) as it torques back out(CW to CCW) at the other side"_
are you just talking random gibberish?
@@CaptainWrinkleBrain _"An electron in a metal normally behaves as a free particle. The electron is repelled from other electrons due to their negative charge, but it also attracts the positive ions that make up the rigid lattice of the metal. This attraction distorts the ion lattice, moving the ions slightly toward the electron, increasing the positive charge density of the lattice in the vicinity. This positive charge can attract other electrons. At long distances this attraction between electrons due to the displaced ions can overcome the electrons' repulsion due to their negative charge, and cause them to pair up. The rigorous quantum mechanical explanation shows that the effect is due to electron-phonon interactions."_
ok but you're not answering the questions: why pairs & not triplets? Why do the pairs experience 0 resistance?
@H T your questions are very good. Perhaps this is what's happening:
1) The 2 electrons forms a single object (known as a singlet)
2) the 2 electrons are very far apart.
3) Electrons are waves so we can regard the Cooper pair as a very long wave.
4) Because the waves are so long there's a lot of overlap with other Cooper pair waves
5) The 2 electrons have opposite spin which means the singlet has zero spin in total
6) Things which have zero spin are bosons
7) Bosons don't have to obey Pauli's exclusion principle which says "2 electrons in the same atom cannot have an identical set of values for the 4 quantum numbers n, l, m, ms"
8) As the electrons are cooled they all fall into the lowest possible energy state with the same 4 quantum numbers.
9) We're talking millions of electron-pair waves. They overlap & strengthen each other like bricks in a wall
10) Since this wall is composed of so many electrons it's solid as fuck.
11) If the electrons formed a triplet the spins wouldn't cancel out = not a boson = not a wall
12) Normally electrons travelling through a wire experience resistance because the atoms in the wire are jiggling & getting in the way of the electrons
13) But here, the atoms in the copper wire aren't jiggling very much cause it's so fing cold. They just don't have the energy to push the solid mass of electrons around
14) Thus there's no resistance
Which playlist should I watch in order to fully understand the electron classification as a fermion? Thanks in advance
Thanks for the video....I have a little question ..can the potentail difference across the battery cause the production of an electric field when then cause the electrons to move around ?
very useful! thanks!
could you please upload more vedio on superconductivity I love the way of your teaching
Yes. But once moving, if there is no resistance then it will continue to flow.
Are the electric field and magnet outside the superconductor, described by maxwell eq??
So we 're considering an electron pair to be a boson because of the total spin which is the sum of their two spins?. Thanks
Is it possible that we're in a sea of dark matter that's everywhere within our expanding universe with the exceptions of not being beyond that edge (perhaps explaining the faster than light speed expansion), not being in the extreme density of black holes (possibly explaining the faster than light speed Hawking Radiation), and perhaps not being within superconductive fields either? Gravitational waves are dark matter density waves, no? Thx
Outstanding
Brilliant video. But how do the electron pairs becoming Bosons, stop them from physically colliding with the lattice structure or the positive copper atoms? And right at the last 5 seconds of the video, why do the magnetic poles exist only on the sides? Why not the centre?
One question. When the electrons combine into a Cooper pair, what about that change allows for zero resistance? The only change is that they become a composite boson, which means they now have a whole number spin. So is the spin responsible for their lack of reaction with protons?
Sounds like Cooper discovered a new type of composite particle, akin to baryons and mesons. Unlike baryons and mesons, which are made up of quarks, These cooper pairs are made with leptons.
Any chance that this may apply to mu electrons or possibly neutrinos?
what are unicorns made up of?
Wouldn't there be a net negative charge in the middle since the electrons will tend to travel on the outside and the lattice will be distorted towards the outside of the wire?
Yes, but once moving, if there is no resistance then it will continue to flow.
Brilliant tutorial!
But electron pairs seem confusing to me as the nucleus still has electrons attached to it at the lower energy level and has a much much larger mass, so they use lower energy electrons as the mortar for the lattice, while squashing the higher energy electrons moment layer together - allowing higher energy electron to move thought he material , and act like a liquid.
But if he material is cooled enough I still don't understand the following - 1) Why electron pairs form to produce a super liquid? (unless your saying electrons can get closer together because their not getting energised by heat) and 2) Ultimately why there is no magnetic field in centre of material and why both end of magnet are repelled? As there still magnetic field produced around each atom.
But you're missing one important item; The Meissner effect surface currents geometry. Egor Babaev made a model proving it as I predicted it using my physics theory in 1996, copyrighted 2002, a few years before his model was even made.
8 charge spins around 1 larger one will stack like 16 around 1 viewed from the top, and give charge a reason form concave and convex fields to and from the source current in order to balance all charge points at once against said field.
In the levitation explanation,could you please explain how the current starts going on ,especially just on top.
Thanks
You show the magnetic field from the superconductor pointing North outwards, but it does not act like a magnet; it opposes both N and S; (hence diamagnetic?).
Also, according to this aweso explanation it turns out we really do not need (only) superconductive materials to levitate magnets, right?
Also, electrons have a spin of 1/2 right? So when cooper pairs form, do the spins add or subtract to make 1 or 0? So they become a boson, with integral spin?
Superb.
really very nice......i understood very well...........
DrPhysicsA sir..u have told that according to meissner effect magnetic field cannot penetrate the metal,so i assume it cannot induce the current on the surface in this case..so,what is the source of the surface current on the metal that flows forever and ever??
Tanvir Kaisar no, its not like it cant pass...i think its that the induced current (eddy current) on the surface produces an equal amount of magnetic field opposite to the magnetic field. Then the flux just cancels out...since its a super conductor..the magnetic field doesnt die down because the current induced will go on forever....same thing happens with regular conductors, but after a while, the current induced by the change of magnetic flux dies down, which allows the magnetic field through it...
Yes. But once moving, if there is no resistance, it will continue to flow.
If a cooper-pair changes energy level together, would that produce a Photon as one Electron would?
Yes, but not exclusively. To quote Wikipedia: "The name phonon comes from the Greek word φωνή (phonē), which translates as sound or voice because long-wavelength phonons give rise to sound. In physics, a phonon is a collective excitation in a periodic, elastic arrangement of atoms or molecules in condensed matter, such as solids and some liquids."
3D+Time is interpreted as 4 dimensions, but if everything is actually Time as mechanism of Quantum Fields and associated spatial-particles, then Superconduction of the type shown should be known as a 4D phenomenon of 2×2D prime planar Cooper pairs occupying the lattice of the conductor simultaneously in a specific example of the "One Electron theory" at or near Zero Kelvin, the Neutron resonance shell. (As a simplified guesstimate of probability behaviour)(?)
Why do like charges repel? I know they exchange photons but then how do opposite charges attract? Do they exchange photons backwards to come towards each other? How do they know the other one is there?
Right, Onnes, the discoverer of superconductivity, cooled mercury with liquid helium to achive a 4.2 kelvin temperature, the other metals have similar superconductivity points.
The YBCO however achives superconductivity at a temperature that can be achieved with liquid nitrogen, this is known as high temperature superconductivity and it's much more affordable and easy than achieving superconductivity with a normal metal, so it's what the youtube videos use
I am currently doing AS physics and for my first piece of coursework I chose to look at superconductors. This video has been a fantastic help and thanks for that, but I would suggest that if you ever do another one you could include at least something on the structure of superconductors specifically and how the structure of them affects their Tc. Also, I personally found/find the use of copper in the example quite confusing, as I didn't think it was a superconductor? Thanks.
Thank you for your kind comments. Upon reflection it probably was not a good idea to use copper as an example since as you say it is not actually a superconductor. As you probably realise, my videos are designed to give a basic introduction to the subject so that someone can then go on to look at the more advanced explanations elsewhere so it's a balance of keeping it simple without being too misleading. I've added an annotation to explain about copper.
DrPhysicsA You are right, and this is a fantastic video to get a basic understanding. I now know that the Tc is related to the mass of the ions in the material, so perhaps another annotation could point that out? Thanks for getting to back to me, I find your videos very informative and I have subscribed :)
DrPhysicsA Good, Good, Also you might wanna add that "Cooper pairs" theory can't explain how does Type 2 Superconductor work... Since you mentioned energy limit for Cooper pair forming is 10^-3 eV , where as Type 2 SCON operates @ 50K-168K..
One last question - is Superconductivity only relevant for DC. It would seem once you take away the AC Voltage, (the pump pulling and pushing) you end of with DC only.
so a cooper pair of electrons is not with an electrical character at all but they transform to something else... how much is the speed of "electrons" passing through a superconductor?
Hi..
Why meissner effect shows itself in other way/in reverse way?
I mean why repels? Why we cannot see attraction.
Why the surface current cannot be the in reverse direction?
Thanks a lot
Hi, I am assuming that the Cooper pairs need kinetic energy to propagate through the conductor. So if the temperature is decreased to 0K, thus there is no kinetic energy in the system, will the Cooper pairs still propagate and will the conductor still be a super conductor? Thanks in advance.
+Ruart Crous The temperature is in essence the average kinetic energy/ Just because the temperature of the copper is 0K does not mean particles cannot pass through it. Any particle passing through the temperature would only loose energy upon a collision. Which never happens. Its like saying as soon as anything enters space it stops moving. Rather it keeps going until a collision removes KE
can you do a video about the penetration depth and coherence length please? thank you! :D
The article on "Cooper Pairs" in Wikipedia is good on this.
best channel ever i always keep coming back thank u for this knowledge
why is there some losses in supracondutor cable in AC and not in DC?
I was leaning toward what Walter said! Except the whole colliding with atoms and the conservation of momentum confuses me! In the electron theory one can have an infinite length of wire when pulled the e- flow must be disrupted....etc...The point is that e- flow should never collide with nuclei causing vibrations B fields at the atomic level with the forces and all the wave particle duality...Massive uncertainty!
if the resistance of the bulb wire goes down shouldnt it glow less? i mean it glows because of heat right? less resistance means less heat and less glow?
But a lower resistance implies a higher current.
I think we're talking about a lower resistance in the wires of the circuit, not the bulb. That allows a stronger current to arrive to the bulb.
Sara Chakir LOL guys, ASK yourselves what causes lamp to "glow".. luckily filament lamp is made of Wolfram not BSCCO. Else we would live in a dark world))))..
The Meisner effect stops working if you increase the strength of the Magnetic field. Then the critical temperature for the metal will decrease. That’s why you can only have a certain amount of current in a superconductive system before it stops working. If you increase the supply of current through the system, the magnetic field strength will increase and the system will experience resistance.
Can you please explain that how will electricity become never-ending? If that was the case, then people would attain superconductivity on a substance and then after passing a current and attaining unlimited energy they could run the plant and cool it forever and have free energy forever.
Good Explanation but the graph should be drawn to the opposite side as to reducing side...if you have marked it it will be ok...
Thank you good sir
isn't the resistance vs temperature curve wrong?
yes
He did the graph so the temperature goes from high at the origin to low on the right so it is right (I think)
Nope it's correct
@@bonnielunel6014 no, it's wrong. As temperature DECREASES, resistance DECREASES. So as temp INCREASES, resistance INCREASES. If Temp is 0, resistance is also 0. This is clear from the formula for resistance, R = (pLT)/A. So the graph should start at 0,0 & increase along both axes.
@@codebulletin NO, it's wrong. As temperature DECREASES, resistance DECREASES. So as temp INCREASES, resistance INCREASES. If Temp is 0, resistance is also 0. This is clear from the formula for resistance, R = (pLT)/A. So the graph should start at 0,0 & increase along both axes.
sir i think this is in case of superconducting rings not straight wires..... persistent current..
So I have a question how do you know what substance to choose to make superconductors sorry for my bad English and thank you for any answers.
Kani Kagami thats the finded thing with mecurcy that only at certain temperature directly come zero and behave as superconductivity no other metal come suddenly to zero