  It is shown how to use non-commutative stopping times in order to stop the
CCR flow of arbitrary index and also its isometric cocycles, i.e., left
operator Markovian cocycles on Boson Fock space. Stopping the CCR flow yields a
homomorphism from the semigroup of stopping times, equipped with the
convolution product, into the semigroup of unital endomorphisms of the von
Neumann algebra of bounded operators on the ambient Fock space. The operators
produced by stopping cocycles themselves satisfy a cocycle relation.
