Collective Lamb Shift in Single-Photon Superradiance
Roehlsberger, Ralf × Schlage, Kai Sahoo, Balaram Couet, Sebastien Rueffer, Rudolf #
Amer assoc advancement science
Science vol:328 issue:5983 pages:1248-1251
Superradiance, the cooperative spontaneous emission of photons from an ensemble of identical atoms, provides valuable insights into the many-body physics of photons and atoms. We show that an ensemble of resonant atoms embedded in the center of a planar cavity can be collectively excited by synchrotron radiation into a purely superradiant state. The collective coupling of the atoms via the radiation field leads to a substantial radiative shift of the transition energy, the collective Lamb shift. We simultaneously measured the temporal evolution of the superradiant decay and the collective Lamb shift of resonant Fe-57 nuclei excited with 14.4-kilo-electron volt synchrotron radiation. Our experimental technique provides a simple method for spectroscopic analysis of the superradiant emission.