excitationscommonly

Excitationscommonly is not a standard term in physics, but this article uses it to denote the class of excitations that are commonly observed across many physical systems. An excitation is a transition from a system's ground state to a higher-energy state induced by energy input, and it often involves collective or individual degrees of freedom.

Common examples include: photons (electromagnetic field quanta), phonons (lattice vibrations in solids), magnons (spin waves in magnets), excitons (bound electron-hole pairs in semiconductors), plasmons (collective oscillations of charge density). Depending on the system, other excitations such as polaritons (mixed light-matter), rotons, or triplons may appear as well.

These excitations are typically characterized by energy-momentum relations (dispersion), lifetimes, and interaction strengths with other excitations and with external fields. They can be localized or delocalized, and may involve single-particle or collective dynamics.

Creation mechanisms include absorption or scattering of photons, thermal fluctuations, electrical or magnetic perturbations, or intrinsic relaxation processes after a disturbance.

Observation methods include optical spectroscopy, Raman scattering, angle-resolved photoemission spectroscopy, inelastic neutron scattering, electron energy loss spectroscopy, and terahertz or microwave probes, depending on the excitation type.

In condensed matter physics and materials science, understanding excitationscommonly helps explain thermal, optical, and transport properties, and informs the design of devices such as LEDs, solar cells, lasers, and quantum information components.