The Quantum Effect Known as Superconduction

Superconduction: The property that occurs in certain materials below a characteristic temperature where they have an electrical resistance of exactly zero.

Superconduction was discovered in 1911 but it was not understood for years do to the lack of a theory to understand it was not yet in place. It turns out that at the critical temperature the electrical resistance suddenly drops to zero.  This basic theory is that at the critical temperature electrons become coupled over a ranger of about 1,000 X the spacing of the conductor’s lattice with a binding energy that is the result of vibration that the electrons cause in the lattice. Called cooper pairs, the coupled electrons effectively becomes a boson and condense into the ground state. The result is that each coupled electron helps the other over come any resistance encountered from the lattice.

The Meissner Effect is where a magnetic field is expelled from a superconductor during the transition to the superconducting state that is caused by electric currents generated near its surface by the applied field. The magnetic field of these currents cancels out the applied magnetic field within the superconductor. This causes the magnetic levitation associated with superconductors.

Superconductivity is a purely quantum effect that has no counter part in classical physics. It’s most commonly known effect is magnetic levitation. It is one of two purely quantum effects that are seen on a macroscopic scale.

Reference

What is superconductivity?

How Do Superconductors Work?

The Quantum Effect called Superfluids

Superfluid: A liquid that has no viscosity and infinite thermal conductivity.

A superfluid appears to be a normal liquid but flows without friction past any surface allowing it to continue to circulate over obstructions and through pores in its container do only to its own inertia.

All of the atoms in a superfluid are in the same quantum state so they all have the same momentum such that if one moves they all move. This allows superfluids to move without friction even through the tiniest of cracks. Superfluid helium will flow up the sides of a jar and over the top.

In conclusion superfluity is a purely quantum effect that has no counter part in classical physics. It is one of two purely quantum effects that are seen on a macroscopic scale.