title: Time-optimal quantum evolution.
abstract: We present a general framework for finding the time-optimal evolution and the optimal Hamiltonian for a quantum system with a given set of initial and final states. Our formulation is based on the variational principle and is analogous to that for the brachistochrone in classical mechanics. We reduce the problem to a formal equation for the Hamiltonian which depends on certain constraint functions specifying the range of available Hamiltonians. For some simple examples of the constraints, we explicitly find the optimal solutions.
authors.affiliation: Department of Physics, Tokyo Institute of Technology, Tokyo, Japan. carlini@th.phys.titech.ac.jp
authors.forename: Alberto
authors.initials: A
authors.lastname: Carlini
authors.forename: Akio
authors.initials: A
authors.lastname: Hosoya
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Koike
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Okudaira