title: Preserving quantum states using inverting pulses: a super-Zeno effect.
abstract: We construct an algorithm for suppressing the transitions of a quantum mechanical system, initially prepared in a subspace P of the full Hilbert space of the system, to outside this subspace by subjecting it to a sequence of unequally spaced short-duration pulses. Each pulse multiplies the amplitude of the vectors in the subspace by -1. The number of pulses required by the algorithm to limit the leakage probability to epsilon in time increases as T exp[square root log(T(2)/epsilon)], compared to T(2)epsilon(-1) in the standard quantum Zeno effect.
authors.affiliation: Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India.
authors.forename: Deepak
authors.initials: D
authors.lastname: Dhar
authors.forename: L K
authors.initials: LK
authors.lastname: Grover
authors.forename: S M
authors.initials: SM
authors.lastname: Roy