Collective Absorption of Blackbody Radiation by Rydberg Atoms in a Cavity: An Experiment on Bose Statistics and Brownian Motion

Abstract

Absorption of blackbody radiation by Rydberg atoms in a resonant cavity is shown to be a collective process in which the atoms behave as a Bose gas. The equilibrium energy of this gas was measured and found equal to twice the photon energy (factor of 2 accounting for atomic transition degeneracy). It is shown that this experiment exhibits the Brownian motion of the atomic-system Bloch vector.