Resonator The guitar resonator is a device for driving guitar string harmonics by an electromagnetic field. This resonance effect is caused by a feedback loop and is applied to drive the fundamental tones, octaves, 5th, 3rd to an infinite sustain. Resonator A resonator is a device or system that exhibits resonance or resonant behavior, that is, it naturally oscillates at some frequencies, called its resonant frequencies, with greater amplitude than at others. The oscillations in a resonator can be either electromagnetic or mechanical (including acoustic). Resonators are used to either generate waves of specific frequencies or to select specific frequencies from
Scattering amplitude quantum mechanical approach is given by the S matrix formalism. The scattering amplitude can be determined by the scattering length in the low-energy regime. Scattering amplitude In quantum physics, the scattering amplitude is the probability amplitude of the outgoing spherical wave relative to the incoming plane wave in a stationary-state scattering process. The latter is described by the wavefunction where formula_2 is the position vector; formula_3; formula_4 is the incoming plane wave with the wavenumber along the axis; formula_5 is the outgoing spherical wave; is the scattering angle; and formula_6 is the scattering amplitude. The dimension of the scattering amplitude