Local control theory for coherent manipulation of population dynamics

Thomas Lindvall, Mikko Merimaa, Ilkka Juhani Tittonen

Michihiko Sugawara

A general local control theory for manipulating quantum system dynamics is developed. Basic concept of the present theory is lying in the realization of monotonous increasing condition of the performance index, which is locally (in time domain) defined to major how the present quantum state satisfies the current objective. The local control field is designed to satisfy the above condition taking into account the equation of motion of the system. It is found, through the formulation, that the monotonous increasing condition can be achieved as long as the performance index is given as a function of expectation values of time-dependent observable operators, whose equation of motion is governed by the field-free system Hamiltonian or Liouvillian. It is also shown that the present theory is a generalization of the local optimization approach which has been successfully applied to many of molecular dynamics control problems. As for the special cases, performance indices for “transition path control,” “population distribution control,” and “wave packet shaping” are proposed. The theory is applied to vibrational control problems of the one-dimensional model system of hydrogen fluoride. The results show that the present method works effectively for the population dynamics control as well as the wave packet shaping.

Feng Shuang, Mianlai Zhou, Alexander Nikolaevich Pechen +3 more

Quantum measurements are considered for optimal control of quantum dynamics with instantaneous and continuous observations utilized to manipulate population transfer. With an optimal set of measurements, the highest yield in a two-level system can be obtained. An analytical solution is given for the problem of population transfer by measurement-assisted coherent control in a three-level system with dynamical symmetry. The anti-Zeno effect is recovered in the controlled processes. Demonstrations show that suitable observations can be powerful tools in the manipulation of quantum dynamics.

Wolfgang Maichen, Rainer Gaggl, Eugeny Korsunsky +1 more

Sergey G. Przhibel'skii

David Gerbasi, Gregory D. Scholes, Paul W. Brumer

Coherent control theory is used to show that one can manipulate biexciton vs exciton populations in semiconductor quantum dots (QDs) in a typical dissipative environment. Both aligned and randomly oriented quantum dots are considered, and population control is shown to be considerable. An application to CdSe QD shows that the proposed coherent control scenario results in a significant reduction in pump intensity for the onset of optical gain.