TY - RPRT T1 - On-line estimation of local oscillator noise and optimisation of servo parameters in atomic clocks AU - Leroux, Ian D. AU - Scharnhorst, Nils AU - Hannig, Stephan AU - Kramer, Johannes AU - Pelzer, Lennart AU - Stepanova, Mariia AU - Schmidt, Piet O. DO - 10.15488/1728 UR - http://www.repo.uni-hannover.de/handle/123456789/1753 AB - For atomic frequency standards in which fluctuations of the local oscillator (LO) frequency are the dominant noise source, we examine the role of the the servo algorithm that predicts and corrects these frequency fluctuations. We derive the optimal linear prediction algorithm, showing how to measure the relevant spectral properties of the noise and optimise servo parameters while the standard is running, using only the atomic error signal. We find that, for realistic LO noise spectra, a conventional integrating servo with a properly chosen gain performs nearly as well as the optimal linear predictor. Using simple analytical models and numerical simulations, we establish optimum probe times as a function of clock atom number and of the dominant noise type in the local oscillator. We calculate the resulting LO-dependent scaling of achievable clock stability with atom number for product states as well as for maximally-correlated states. KW - Atomic frequency standards KW - Local oscillator noise KW - Quantum projection noise KW - Servo optimisation KW - Atomic clocks KW - Frequency standards KW - Optimization KW - Frequency fluctuation KW - Local oscillator frequencies KW - Local oscillators KW - Optimal linear prediction KW - Optimisations KW - Spectral properties KW - Parameter estimation KW - Dewey Decimal Classification::500 | Naturwissenschaften::550 | Geowissenschaften PY - 2017 PB - Bristol : Institute of Physics Publishing LA - en ER -