Resonante

Resonante, or resonant, describes a property of a system that responds with large amplitude when driven at or near one of its natural frequencies. When a periodic force matches a system’s eigenfrequency, energy is efficiently transferred into the corresponding mode, causing sustained oscillations even if the driving force is relatively small. The frequency at which this occurs is the resonant frequency.

Real systems exhibit damping, which reduces peak response and broadens the resonance. The sharpness of resonance is quantified by the quality factor, or Q: higher Q means a more selective response with a narrower bandwidth. Resonance can be mechanical, acoustic, electrical, optical or quantum, depending on the system's dominant restoring force and energy storage mechanism.

Examples include mechanical resonance in a swinging pendulum or a vibrating bridge, acoustic resonance in air columns of instruments like a flute, and electrical resonance in LC circuits and radio receivers. In optics, resonant cavities and plasmonic structures concentrate light at specific wavelengths. Sympathetic resonance occurs when one object causes another to vibrate at the same frequency.

Applications exploit resonance for tuning, filtering and sensing, while engineers must mitigate unwanted resonance to prevent fatigue, noise, or structural failure. The term resonante is common in Spanish and Italian as a direct translation of resonant; in English, resonant is used similarly, and the phrase "resonates with" describes ideas or sounds that evoke similar responses.