动力学去耦提升N@C_（60）@C_（60）H_（28）单晶中电子自旋相干时间的实验研究

内嵌富勒烯N@C60与C60H28分子共结晶形成的单晶N@C60@C60H28,能够实现N@C60的有序排列,从而在实现基于内嵌富勒烯的可扩展量子计算上具有着突出的潜力.本项研究中,我们对单晶N@C60@C60H28中氮电子自旋的弛豫时间和弛豫机制做了详细的测试和分析,厘清了N@C60@C60H28样品中氮电子自旋相干时间（T2）降低的主要原因来自C60H28分子中质子核自旋热库的影响.通过动力学去耦实验技术,我们进一步有效地抑制了这一不利影响,实现了氮电子自旋T2时间的显著提升.这一研究结果对于更好地保护编码于有序富勒烯内电子自旋上的量子信息,进而实现量子计算,具有重要的意义.     

Optimizing ultrasensitive single electron magnetometer based on nitrogen-vacancy center in diamond

The measurement of the weak magnetic field in nanoscale resolution and at room temperature is always a significant topic in biological, physical, and material science. Such detection can be used to decide the characterization of the samples, such as cells, materials, and so on. Nitrogen-vacancy (NV) center in diamond has been proved to be able to detect a magnetic field with nano Tesla sensitivity and nanometer resolution at room temperature. Here we experimentally demonstrate an optimized NV center based single electron magnetometer in a commercial diamond and under a home-built optically detected magnetic resonance (ODMR) microscope. With current technology, we change the optically detected time window to get a better signal to noise ratio, and use dynamical decoupling to increase the slope of magnetic field amplitude versus fluorescence signal. By employing the 8-pulse XY-4 dynamical decoupling sequence we achieve a sensitivity of 18.9 nT (Hz)(1/2) , which is 1.7 times better than spin echo. We also propose a NV center based scanning diamond microscope for electron and nuclear spins detection as well as nanoscale magnetic resonance imaging. If it is realized, the NV center based magnetometry will have wide application in the future.