Unraveling spin dynamics from charge fluctuations

The use of single electron spins in quantum dots as qubits requires detailed knowledge about the processes involved in their initialization and operation as well as their relaxation and decoherence. In optical schemes for such spin qubits, spin-flip Raman as well as Auger processes play an important role, in addition to environment-induced spin relaxation. In this paper, we demonstrate how to quantitatively access all the spin-related processes in one go by monitoring the charge fluctuations of the quantum dot. For this, we employ resonance fluorescence and analyze the charge fluctuations in terms of waiting-time distributions and full counting statistics characterized by factorial cumulants.