Measurements continuous in time and a posteriori states in quantum mechanics

  title={Measurements continuous in time and a posteriori states in quantum mechanics},
  author={Alberto Barchielli and Viacheslav P. Belavkin},
  journal={Journal of Physics A: Mathematical and General},
Measurements continuous in time have been consistently introduced in quantum mechanics and applications worked out, mainly in quantum optics. In this context a quantum filtering theory has been developed giving the reduced state after a measurement when a certain trajectory of the measured observables is registered (the a posteriori states). In this paper a new derivation of filtering equations is presented for the cases of counting processes and of measurement processes of diffusive type. It… 

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