Limits on atomic qubit control from laser noise

Abstract Technical noise present in laser systems can limit their ability to perform high fidelity quantum control of atomic qubits. The ultimate floor for qubits driven with radiation is due spontaneous emission from excited energy levels. goal suppress the technical source below such that it no longer a limiting factor. It has been shown spectral structure have large influence on achievable fidelities, while prior studies contributions restricted magnitudes. Here, we study unique and introduce metric determines when stabilised optimised We find requirements stabilisation bandwidths be orders magnitude higher than those required simply narrow linewidth laser. introduced metric, ? -separation line, provides tool engineering sources floor.