International Collaboration in Chemistry: Decoherence control via quantum dynamical decoupling - theory and experiment

量子信息有望给科学技术的各个领域带来革命性的变化。它的实施主要受到退相干的阻碍，即由于量子系统与其环境不想要的和不受控制的耦合而造成的信息损失。该项目旨在通过应用脉冲序列来减少这种影响，这些脉冲序列旨在重新聚焦或解耦量子系统与其环境之间的相互作用。这个想法与自旋-回声效应密切相关，但在这里，研究人员应该考虑一种更一般和更健壮的方法，旨在任意长时间的相干保持。虽然量子相干性的保存对于人们希望存储量子状态的“量子存储器”应用是必不可少的，但量子计算机需要额外的进步：它应该能够可靠地处理量子信息。这是研究人员计划做出贡献的第二个领域，同样是通过在核磁共振设置中使用动态解耦。为了实现这一目标，我们将结合量子纠错码和动态解耦的无相干子空间等技术。这将使我们能够将信息处理与其对消相干的保护结合起来。

Quantum information promises to revolutionize various fields of science and technology. Its implementation is hampered mostly by decoherence, the loss of information due to unwanted and uncontrolled couplings of the quantum system with its environment. This project aims at reducing this effect by applying pulse sequences designed to refocus or decouple the interaction between the quantum system and its environment. This idea is closely related to the spin-echo effect, but here the investigators shall consider a much more general and robust approach, aimed at arbitrarily long coherence preservation. While preservation of quantum coherence is essential for “quantum memory” applications, where one wishes to store a quantum state, quantum computers require an additional advance: it should be possible to process quantum information reliably. This is the second area where the investigators plan to make a contribution, again by using dynamical decoupling in an NMR setting. To accomplish this goal, we will combine techniques such as quantum error correcting codes and decoherence-free subspaces with dynamical decoupling. This will enable us to combine information processing with its protection against decoherence.