An essential prerequisite for quantum information processing (QIP) is precise coherent control of the dynamics of quantum systems or quantum bits (qubits). Most of the control sequences implemented in quantum experiments are developed and designed based on the assumption of having ideal (closed) quantum coherent systems. However, almost every quantum system interacts inevitably with its surrounding environment resulting in decoherence and dissipation of the quantum system. Furthermore, before any operation or measurement is performed onto the system, the system is often correlated with its environment in a joint system-environment equilibrium state. Thus precisely controlling realistic open quantum systems is one of the most important and timely issues in the field of QIP.
Here, we investigate how the initial system-environment correlation affects the open system dynamics and the state preparation as opposed to commonly adopted initial factorization approximation of the system-environment state. In addition, we employ quantum optimal control theory (QOCT) based on the Krotov method to find control pulse sequences of fast and high-fidelity quantum gates taking into account decoherence from dissipative environment for various promising physical quantum systems, such as donor-based and NV-center-based spin-qubit systems and superconducting Josephson-junction-based qubit systems.

                                              （联系人：吕智国）