In the late forties Richard Feynman (1948) proposed a path-integral form of quantum mechanics that proved to be equivalent to the conventional Schrödinger-equation form but possessed a much more heuristic force (see Feynman and Hibbs (1965) for a detailed exposition of Feynman’s theory). Our consideration of continuous measurements in the following chapters will be based on Feynman path integrals. A theory of quantum continuous measurements will be formulated directly in terms of path integrals instead of a limiting process of the type used in Chapter 2 .
A Cameron-Martin formula is established for the Feynman map definition of the Feynman integral in non-relativistic quantum mechanics. This formula involves the Morse or Maslov indices and shows the connection with the Feynman-Hibbs definition of the path integral and the Fresnel integrals of Albeverio and Hoegh-Krohn. Applications are given to the Feynman-Kac-Ito formula for anharmonic oscillator potentials On etablit une formule de Cameron-Martin pour l'integrale de Feynman en mecanique quantique non relativiste. Cette formule fait intervenir les indices de Morse et de Maslov et montre la relation avec la definition de Feynman-Hibbs de l'integrale de chemins et les integrales de Fresnel considerees par Albeverio et Hoegh-Krohn. On donne des applications a la formule de Feynman-Kac-Ito pour des potentiels d'oscillateurs anharmoniques