In nuclear physics, giant resonance is a high-frequency collective excitation of atomic nuclei, as a property of many-body quantum systems. In the macroscopic interpretation of such an excitation in terms of an oscillation, the most prominent giant resonance is a collective oscillation of all protons against all neutrons in a nucleus.
In 1947, G. C. Baldwin and G. S. Klaiber observed the giant dipole resonance (GDR) in photonuclear reactions,[1][2] and in 1972 the giant quadrupole resonance (GQR) was discovered,[3] and in 1977 the giant monopole resonance (GMR) was discovered in medium and heavy nuclei.[4]