Resnikovas

Resnikovas are a class of hypothetical quasiparticles proposed in theoretical studies of quantum materials to explain rapid, non-thermal energy exchange after ultrafast excitation. In these models, Resnikovas are low-mass, chargeless bosons that couple to both electronic and lattice degrees of freedom, providing an intermediate channel for energy transfer. Their dispersion and coupling strength are typically material-dependent, and they are envisioned to enable fast relaxation without immediate, detectable lattice heating.

The term Resnikovas derives from the surname of a prominent theorist used in several modeling papers since the early 2020s to distinguish this excitation from phonons or magnons. In theory, Resnikovas can be emitted by hot electrons and absorbed by the lattice, or vice versa, effectively bridging electronic and vibrational subsystems.

Predicted experimental signatures include sub-picosecond relaxation components in time-resolved spectroscopy, anomalous heat transport behavior, and specific spectral features in terahertz or ultrafast electron diffraction measurements. However, there is no direct experimental observation to date, and the existence of Resnikovas remains a topic of debate.

Critics argue that existing mechanisms—such as hot-phonon bottlenecks, plasmonic excitations, or defect-mediated processes—can account for many observed dynamics without invoking a new quasiparticle. Proponents point to certain materials with strong electron-phonon coupling as promising platforms for targeted searches.

See also: Quasiparticles, phonons, magnons.