Transition probabilities for a Rydberg atom in the field of a gravitational wave

Abstract

The possibility of an atomic detection of gravitational waves on earth is considered. The combination of extremely high lifetimes and resulting small radiative transition probabilities with rapidly growing interaction strength for Rydberg atoms having principal quantum numbers in a region $10^4\ldots 10^5$ might result in transition probabilities which are high enough to open up such a possibility. Transition probabilities and absorption cross sections are calculated as a function of the relevant quantum numbers of a highly excited electron. The orders of magnitude for the transition rate are evaluated for a realistic source of gravitational radiation. It is shown that no specific particle property enters the expression for the absorption cross section for gravitational waves. The only fundamental constant contained in this cross section is, apart from the fine structure constant $\alpha$, the Planck length $L^*=(\hbar G /c^3)^{1/2}$.