Containment of decoherence in the control of logical quantum bits and quantum registers

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Realizing quantum information processing is a particularly complex task because detrimental interactions with the environment perturb the wanted time evolution representing the information processing. In addition, the coherent control of quantum registers, i.e., sets of quantum bits, must be robust against small imperfections and it should work with minimal energy input. Dynamic decoupling, optimum control and quantum error correction are main concepts to make progress in this regard. Their respective advantages shall be combined in this project in a bottom-up approach. Dynamic decoupling is fit to suppress low-frequency noise. Error correction algorithms assume rapidly decaying correlations in the noise so that they are fit to suppress high-frequency noise. The intended theoretical approach starts from the physical quantum bits realized experimentally and studies how logical quantum bits can be encoded into them in an optimized and robust way. The optimization and robustness of the gates switching the logical quantum bits is the next goal. Analytical as well as numerical tools will be employed in parallel to benefit from their respective strengths.