Intensity of a linear absorption resonance of atoms trapped in an anharmonic potential

For atoms trapped in an anharmonic potential, a resonance of homogeneous width occurs at the center of an absorption line in the linear approximation with respect to the field. Quantum kinetic equations are derived for an atom trapped in an arbitrary potential and these are used to study the resonance intensity as a function of anharmonic corrections to the expansion of the potential near the bottom of the well.