Nuclear Gamma-Ray Superradiance

Bernhard W. Adams

Argonne National Laboratory

Superradiance and subradiance are phenomena of collective spontaneous emission from an ensemble of excited atoms. To some extent it can be understood classically as radiation from a phased antenna array, but there are some purely quantum-optical aspects to it, especially so if exactly one photon is involved (which is the case here).

The term of superradiance was originally introduced by R.H. Dicke [1] to describe emission from nuclear-spin resonance at microwave frequencies, it is well-known at near-visible wavelengths, and has also been observed in nuclear gamma-ray resonance.

The talk gives an introduction to superradiance and nuclear gamma-ray resonance. Then, the special case of nuclear gamma-ray superradiance will be described, experimental results (not by BWA) shown, and a way to control nuclear gamma-ray superradiance will be proposed.

As a lead-in to the topic of nuclear gamma-ray superradiance, an overview of synchrotron radiation sources and future x-ray free-electron lasers will be given, and some past and possible future quantum-optical experiments with x-rays will be shown.

[1] R.H. Dicke, Coherence in spontaneous radiation processes, Phys. Rev. 93, 99-110 (1954)