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

实现量子信息处理是一项特别复杂的任务，因为与环境的有害相互作用会干扰代表信息处理的所需时间演化。此外，量子寄存器的相干控制，即，量子比特组必须对小的缺陷具有鲁棒性，并且它应该以最小的能量输入工作。动态解耦、最优控制和量子误差校正是目前在这方面取得进展的主要概念。本项目将采用自下而上的方法，结合各自的优势。动态解耦适合于抑制低频噪声。误差校正算法假设噪声中的相关性快速衰减，使得它们适合于抑制高频噪声。预期的理论方法从实验实现的物理量子比特开始，并研究如何以优化和鲁棒的方式将逻辑量子比特编码到它们中。下一个目标是逻辑量子比特交换门的优化和鲁棒性。分析工具和数值工具将并行使用，以利用各自的优势。

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.