Superconductivity: infinite conductive capacity of a material.
All materials normally possess some degree of resistance that impedes any electric current flowing through them. This resistance can be described as a kind of friction resistance of the ►electrons — electricity particles — in their passage through the atomic lattice. It makes the material heat up at the flow of current and deprives that current of energy.
Superconductive materials lose their electrical resistance entirely when below a certain temperature. Theoretically, current can circulate in such materials for an infinite amount of time without ever losing any energy. In practice, however, the magnetic field that builds up around any electric circuit ensures that the superconductor breaks down at a certain amperage. Nonetheless, superconductivity is used commercially in the construction of particularly strong and loss-free electric magnets and electric motors by means of coils made of deep-frozen wire.
Superconductivity is a phenomenon of ►quantum theory based on the coupling of two electrons at a time to create a so-called Cooper pair, which can move entirely without friction in the material. This quantum-mechanical coupling of elementary particles is also called entanglement. It creates a multitude of strange effects and is the basis of the ►quantum computer. The high-temperature superconductivity discovered in the 1990s cannot be explained in terms of Cooper pairs but results from another, yet unknown, mechanism.