Kramers

Kramers is a Dutch surname. In scientific usage, the name most often refers to Hendrik Anthony Kramers (1894–1952), a Dutch theoretical physicist and professor at Leiden University whose work helped advance quantum mechanics and statistical mechanics. Kramers is associated with several foundational ideas and equations in physics. Kramers' turnover describes how the rate of a thermally activated reaction changes with environmental friction, showing a maximum at intermediate friction. The related Kramers escape rate addresses the escape of a particle from a potential well under damping. Kramers degeneracy is a theorem in quantum mechanics stating that, in systems with time-reversal symmetry and half-integer spin, energy levels are at least doubly degenerate.

In spectroscopy and optics, the Kramers-Kronig relations link the real and imaginary parts of a material's response function, reflecting causality; these relations were developed independently by Kramers and Ralph Kronig in the late 1920s and early 1930s.

The surname Kramers also appears among other individuals and families, particularly in Dutch- and German-speaking regions, but without further specification it does not point to a single universally recognized concept other than the scientific terms named for Hendrik A. Kramers. The term Kramers, therefore, may be encountered in discussions of reaction-rate theory, quantum degeneracy, and linear response theory.