In recent decades there has been a rapid development of methods to experimentally control individual quantum systems. A broad range of quantum control methods has been developed for two-level systems, however the complexity of multi-level quantum systems make the development of analogous control methods extremely challenging. Here, we exploit the equivalence between multi-level systems with SU(2) symmetry and spin-1/2 systems to develop a technique for generating new robust, high-fidelity, multi-level control methods. As a demonstration of this technique, we develop new adiabatic and composite multi-level quantum control methods and experimentally realise these methods using an 171Yb+ ion system. We measure the average infidelity of the process in both cases to be around 10−4, demonstrating that this technique can be used to develop high-fidelity multi-level quantum control methods and can, for example, be applied to a wide range of quantum computing protocols including implementations below the fault-tolerant threshold in trapped ions.
@article{arxiv.1708.02634,
title = {Generation of high-fidelity quantum control methods for multi-level systems},
author = {J. Randall and A. M. Lawrence and S. C. Webster and S. Weidt and N. V. Vitanov and W. K. Hensinger},
journal= {arXiv preprint arXiv:1708.02634},
year = {2018}
}