Can superconductors conduct electricity at absolute zero?

[Nemika]

I've just learned that the conductivity of super conductors increases with decrease in temperature and it becomes infinite at absolute zero. But I thought that all motion ceases at absolute zero. So how can current flow in such conditions? And how can its resistance become zero as some resistance is also offered by the positive ions or maybe the positive charge?

 

[Space Dragon]

In superconducting materials electrons form pairs known as cooper pairs.When two electrons move towards a positive ion they tend to reach an equilibrium state and become electrically bonded.These cooper pairs are responsible of electrical conductivity in a superconductor.The movement of these cooper pairs lead to photon emission making them to propagate easily through the lattice.Refer BCS theory for more info.

 

[Nemika]

But can you clear the point that how can current flow at absolute zero when it is theoretically said that all motion ceases at absolute zero.

 

[Karan Punjabi]

Yes at absolute zero the current flow. From my point of view the atoms have zero kinetic energy but electrons continue to move.

 

[Nemika]

Ok. Thanks anyways.

 

[ZapperZ]

I've just learned that the conductivity of super conductors increases with decrease in temperature and it becomes infinite at absolute zero. But I thought that all motion ceases at absolute zero. So how can current flow in such conditions? And how can its resistance become zero as some resistance is also offered by the positive ions or maybe the positive charge?

Please note that for superconductors, the DC conductivity goes to infinity at and below Tc, the superconducting critical temperature, and not just at absolute zero. This means that for some superconducting compound, this critical temperature can be as high at 130 K.

Zz.

 

[Space Dragon]

Its very hard to freeze a electron.Since electrons are leptons they do not react by mass,that loss of kinetic energy of a substance doesn't stop all electrons.Its because the no of electrons is far greater than the number of positive ions.Hence there is always electromagnetic fluctuations in a substance.So electrons do move due to flux variations.This makes it very difficult to reach absolute temperature.

 

[Drakkith]

Its very hard to freeze a electron.Since electrons are leptons they do not react by mass,that loss of kinetic energy of a substance doesn't stop all electrons.Its because the no of electrons is far greater than the number of positive ions.Hence there is always electromagnetic fluctuations in a substance.So electrons do move due to flux variations.This makes it very difficult to reach absolute temperature.

I don't think this is correct. Absolute zero is impossible to reach because it is impossible to exactly cancel out all the different vibrations, rotations, and translations that the particles composing a material are undergoing. In addition, the existence of a ground state prevents electrons from losing all of their momentum anyways.

I don't know what 'react by mass' means.

 

[Space Dragon]

I said that because electrons has less mass compared to a positive ion,they react electromagnetically rather than gravitationally(ie.by mass).
I may be wrong but i still don't see any plausible explanation to her question.
Thanks for correcting me anyways.

 

[Drakkith]

I said that because electrons has less mass compared to a positive ion,they react electromagnetically rather than gravitationally(ie.by mass).

Well, no, that's not correct either. We can effectively ignore gravitation here, as it has little to nothing to do with why absolute zero is impossible to reach or why superconductors behave the way they do.

But can you clear the point that how can current flow at absolute zero when it is theoretically said that all motion ceases at absolute zero.

That's a misconception. Motion does not cease at absolute zero. Instead, the particles making up the material would be in their ground state, which is a minimum energy level. They literally cannot lose any more energy and stop moving.