Timeoptimal Quantum Computing via Optimal Control in Finite Dimensions: Spin Systems and beyond
Thomas Schulte‐Herbrüggen · AIP conference proceedings · 2004
Timeoptimal quantum computing provides a dramatic speed‐up in realistic coupling networks of qubits, wherever the time‐limiting steps are coupling evolutions, while local controls are fast. Already in a chain of six spin qubits the timeoptimal quantum Fourier transform obtained by optimal control is some six times faster than the standard decomposition into controlled phase and Hadamard gates. Here, new results of quantum control are presented within their Lie‐theoretical framework sketched from the preconditions of controllability and reachability up to recent methods of gradient flows.