Achieving decoherence suppression in open quantum systems by utilizing the model of environmental interactions

In this paper, we study the problem of suppressing Decoherence in open finite-dimensional quantum systems by effectively making use of the geometric and structural properties of the open quantum system and the model of the environmental interaction. It is shown that both the geometric properties of the system as well as the structure of decohering environmental interaction play a vital role in successful decoherence suppression. We re-formulate the problem of decoherence suppression as a disturbance rejection scheme, in which the environmental interaction is treated as the quantum disturbance. The conditions for “decouplability” is given along with a detailed constructive algorithm to synthesize the decoupling control of with the help of a scalable ancillary quantum system. This decoherence suppression strategy is demonstrated for a simple 2-qubit system wherein the effects of decoherence are completely eliminated. The theory provides conditions to be imposed on the controller to ensure perfect decoupling.