Superconduction an Effect of Quantum Mechanics

The property that occurs in certain materials below a characteristic temperature where they have an electrical resistance of exactly zero is called superconduction. Discovered in 1911 it took years to find a theory that allowed superconduction to be understood.

At a critical temperature that varies with the substance the electrical resistance will suddenly drops to zero.  The 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.

Superfluids a stange Quantum Effect

A superfluid is a liquid that has no viscosity and infinite thermal conductivity. Superfluids appears as normal liquids but flow 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.

The atoms in a superfluid all exist in the same quantum state so they all have the same momentum such that if one moves they all move allowing 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. 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.