høytilstanden

Høytilstanden, literally the "high state" in Norwegian, is a term used primarily in physics and chemistry to describe a state of higher energy in a system compared with its ground state (lavtilstanden). The concept is most often encountered in quantum mechanics, atomic and molecular spectroscopy, and materials science, where particles occupy discrete energy levels.

In quantum systems, høytilstanden refers to any energy eigenstate with energy above the ground state. When a system is in such a state, its properties—such as absorption and emission spectra, transition probabilities, and lifetimes—differ from those of the ground state. Population of høytilstanden can be achieved by thermal excitation, photon absorption, electrical pumping, or other external perturbations. These excited states are typically transient, relaxing back to lower levels through radiative (photon emission) or non-radiative processes, transferring energy to the surroundings.

In spectroscopy and laser physics, promoted populations of høytilstanden underpin many phenomena, including fluorescence, phosphorescence, and, under certain conditions, population inversion that enables stimulated emission and light amplification.

Outside physics, høytilstanden can be used metaphorically to describe a heightened state of activity, readiness, or performance, though this usage is less formal and highly context-dependent.

See also: ground state, excited state, energy level, spectroscopy, quantum mechanics.