Abstract
The fidelity between the state of a continuously observed quantum system and the state of its associated quantum filter, is shown to be always a submartingale. The observed system is assumed to be governed by a continuous-time Stochastic Master Equation (SME), driven simultaneously by Wiener and Poisson processes and that takes into account incompleteness and errors in measurements. This stability result is the continuous-time counterpart of a similar stability result already established for discrete-time quantum systems and where the measurement imperfections are modelled by a left stochastic matrix.
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Amini, H., Pellegrini, C. & Rouchon, P. Stability of continuous-time quantum filters with measurement imperfections. Russ. J. Math. Phys. 21, 297–315 (2014). https://doi.org/10.1134/S1061920814030029
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DOI: https://doi.org/10.1134/S1061920814030029