Nuclear γ-ray superradiance

Nuclear gamma-ray-resonant superradiance is discussed, comparing Dicke's original approach [1] and recent extensions [2,3] of Scully et al. [2-5] involving conditional excitation to the classical resonant-scattering [6-10] and the Hannon-Trammell [11-14] quantum theories. Relevant questions are whether the sample is optically thin or thick in the excitation and re-radiation processes, the role of superpositions between ground and excited states, Fermi's golden rule, and decoherence due to spatially-dependent near-field interactions [15-17]. The relation of these considerations to experimental results is discussed.