报告人介绍：
   1990年，在中国科学技术大学近代物理系获理学博士。从1998年开始致力于用NMR（核磁共振）方法作量子计算研究工作，是国内最早从事量子计算实验研究的科研工作者之一。 2002年~2003年，访问英国牛津大学量子计算中心和剑桥大学量子计算中心。 最近，他领导的研究小组和香港中文大学合作，通过电子自旋共振实验技术，在国际上首次通过固态体系实验实现了最优动力学解耦，极大地提高了电子自旋相干时间。该成果发表10月29日出版的国际权威杂志《自然》上。审稿人认为“该工作有效地保持了固态自旋比特的量子相干性，对固态自旋量子计算的真正实现具有极其重要的意义”。

摘要: For quantum coherence of electron spins in solids to be exploited in future technologies such as quantum computing, it is essential to overcome the spin decoherence due to coupling to noisy environments. Dynamical decoupling (DD), which uses stroboscopic spin flips to average the coupling to environments to be effectively zero, is a particularly promising strategy for combating decoherence as it can be naturally integrated with function controls such as quantum gates. Since errors are inevitably introduced in each spin-flip control, one should ideally use the minimum number of pulses to realize DD to a certain order of precision. Such optimal DD sequences have recently been explored. The experimental realization of optimal DD in solid-state systems, however, remains elusive. Here we use pulsed electron paramagnetic resonance (EPR) to experimentally demonstrate the optimal DD for preserving electron spin coherence in irradiated malonic acid crystals from 50~K to room temperature. Using a 7-pulse optimal DD sequence, we prolonged the spin coherence time to 31us, which would otherwise be about 0.04us without control or 6.5us under one-pulse control. By comparing experiments to microscopic theories, we identified relevant electron spin decoherence mechanisms in solids. The optimal DD may be applied to other solid-state systems, such as diamonds with nitrogen-vacancy centers. Our work may lay a foundation for quantum coherence control in solids at room temperature.