[The french tourist]

Could someone explain me how superconductivity works the way it does please ? I heard about fractal structures or one electron travelling with another so that there is no energy lost in the metal because of Joule effect... How is this possible ?

[Widdekind]

Is not a Cooper Pair a spinless boson ? If so, then CPs have no magnetic moment, i.e. "the electrons are spinning oppositely, and so their spins, and magnetic moments, cancel" ?? Would "magnetic neutrality" help CPs propagate, without resistance ??

[area_51]

If the medium is at thermal equilibrium within itself and the specific entropy of the medium is higher than the electron, the medium will not tend to energetically interact with the electron. Supercooling forces the medium to dump all the photons possible, proportional to its macroscopic temperature, spreading the remaining energy of the system/medium as evenly as possible throughout other dynamics within. The medium is at thermal equilibrium with itself. It will not have a tendency to absorb energy from its environment as this would decrease its entropic state. The electron continues on without any force acting upon it.

[Klaynos]

area_51, on 3 February 2012 - 08:09 AM, said:

If the medium is at thermal equilibrium within itself and the specific entropy of the medium is higher than the electron, the medium will not tend to energetically interact with the electron. Supercooling forces the medium to dump all the photons possible, proportional to its macroscopic temperature, spreading the remaining energy of the system/medium as evenly as possible throughout other dynamics within. The medium is at thermal equilibrium with itself. It will not have a tendency to absorb energy from its environment as this would decrease its entropic state. The electron continues on without any force acting upon it.

Would you be so kind as to present some references for this as it looks a lot like made up word salad...

[area_51]

Look in any 1st year thermodynamic text and you will see the same type of word salads.

The thing is, this salad only has one ingredient- thermal dynamics. Any other theories of superconductivity that I have seen involve a much more complex word salad of strong force, weak force and EM dynamics all tossed together.

Klaynos, on 3 February 2012 - 09:48 AM, said:

Would you be so kind as to present some references for this as it looks a lot like made up word salad...

[swansont]

Widdekind, on 1 February 2012 - 09:21 PM, said:

Is not a Cooper Pair a spinless boson ?

No, being a boson means integral spin. A Cooper pair can have spin 0 or spin 1.

[Klaynos]

area_51, on 4 February 2012 - 06:24 PM, said:

Look in any 1st year thermodynamic text and you will see the same type of word salads.

The thing is, this salad only has one ingredient- thermal dynamics. Any other theories of superconductivity that I have seen involve a much more complex word salad of strong force, weak force and EM dynamics all tossed together.

Maths is the language of physics, often words make things more complicated because our language was not designed for explaining such things. Your discussion of superconductivity did not fit with the cooper pair explanation I am familiar with. I wanted references to try and reconcile to two or see whether what you said had any backing. You have not produced any references, I therefore cannot make that comparison and based on what you have said I must assume it counters the mainstream accepted theory. I am happy to be corrected if you do have some references for me to read?

[Widdekind]

swansont, on 4 February 2012 - 08:36 PM, said:

No, being a boson means integral spin. A Cooper pair can have spin 0 or spin 1.

If CPs have zero spin, then they have zero magnetic moment, too ?

[Abidal Sala]

At very low temperatures, some metals and alloys conduct electricity without any resistance. The current in these superconductors can flow for billions of years without losing any energy. As electrons become coupled and all move together, avoiding the collisions that cause electrical resistance, they approach a state of perpetual motion. In the laboratory, currents have been maintained for many years and physicists estimate such a current would last for billions of years before losing any energy.

[swansont]

Widdekind, on 6 February 2012 - 03:48 AM, said:

If CPs have zero spin, then they have zero magnetic moment, too ?

The electrons can be physically separated, so I think there are instances where the magnetic moment is not zero for an S=0 system.

[Santalum]

area_51, on 3 February 2012 - 08:09 AM, said:

If the medium is at thermal equilibrium within itself and the specific entropy of the medium is higher than the electron, the medium will not tend to energetically interact with the electron. Supercooling forces the medium to dump all the photons possible, proportional to its macroscopic temperature, spreading the remaining energy of the system/medium as evenly as possible throughout other dynamics within. The medium is at thermal equilibrium with itself. It will not have a tendency to absorb energy from its environment as this would decrease its entropic state. The electron continues on without any force acting upon it.

So in short it is the constant shifting of electrons to and from excited states in the metal that causes electrical resistance to a current. Both due to collisions between transitioning electrons and electrons forming the electrical current or from electrons being lost from the current due to them entering an excited state etc.

Is that roughly the story in very simplistic terms?

This post has been edited by Santalum: 6 February 2012 - 01:09 PM

[Widdekind]

Abidal Sala, on 6 February 2012 - 06:53 AM, said:

At very low temperatures, some metals and alloys conduct electricity without any resistance. The current in these superconductors can flow for billions of years without losing any energy. As electrons become coupled and all move together, avoiding the collisions that cause electrical resistance, they approach a state of perpetual motion. In the laboratory, currents have been maintained for many years and physicists estimate such a current would last for billions of years before losing any energy.

That sounds like Newton's law of motion, "a body in motion tends to stay in motion, unless acted upon by an outside force"; for the interiors of SCs. Er go, CPs in SCs "experience no outside forces", i.e. are non-interacting ??

area_51, on 3 February 2012 - 08:09 AM, said:

If the medium is at thermal equilibrium within itself and the specific entropy of the medium is higher than the electron, the medium will not tend to energetically interact with the electron.

So, the boson-like CPs form a BEC, of low (relative) entropy ?