Meissner effect

This term describes a specific quantum mechanical phenomenon where a superconductor actively expels all interior magnetic fields. It is the defining characteristic that distinguishes a true superconductor from a perfect conductor, as the effect occurs regardless of whether the material was cooled before or after the application of the magnetic field.

In a technical context, this is the primary mechanism behind quantum levitation, where a magnet is suspended above a superconducting material. Because the term is named after physicist Walther Meissner, it is typically treated as a proper noun phrase in scientific literature.