How many photons can a molecule scatter before its coherence is lost?

Abstract

Molecular qubits held in conservative optical traps may lose coherence when they scatter photons from the trapping lasers. The rate for this process has two parts, one equal to the mean Raman scattering rate of the two qubit states, and the other proportional to the square of the difference in their Rayleigh scattering amplitudes. This paper calculates the decoherence rate, expressing results in terms of the vector and tensor parts of the molecular polarizability, ${\alpha }_1$ and ${\alpha }_2$. While the decoherence rate is generally much larger for molecules than for atoms, it is suppressed at wavelengths where ${\alpha }_1$ and ${\alpha }_2$ are both small. The wavelengths where this occurs are identified for CaF molecules.