Klein paradox

Etymology
Discovered by physicist in 1929.

Noun

 * 1)  A surprising result of applying the Dirac equation to the problem of electron scattering from a potential barrier. In non-relativistic quantum mechanics, electron tunnelling into a barrier is observed, with exponential damping. However, if the potential is of the order of the electron mass, $$V\sim mc^2$$, the barrier is nearly transparent; moreover, as the potential approaches infinity, the reflection diminishes and the electron is always transmitted.