Cooling and optical systems of a nanodiamond in a magneto-gravitational trap towards the generation and detection of a spatial superposition state

钻石中的单氮(NV-)中心具有孤立的电子自旋和核自旋，可以在室温下存储量子信息超过一秒。利用磁引力陷阱使纳米钻石悬浮，理论上认为，一旦冷却，纳米钻石可以放置在空间状态的叠加中。长期目标是，这种方法将测试空间叠加态的宏观极限。PHD项目首先建立磁引力陷阱，以便在室温和压力下实现一致的陷阱。下一步是实施真空和氦气体冷却系统，这将使装有捕集器的腔体分别达到高真空和8K。除了真空和冷却系统，PHD项目还将包括设计和建造所需的光学和电子装置，以便对捕获的纳米钻石进行所需的测量。其中包括NV中心光致发光的激发和检测设置。然后，PHD项目将着手检测和核实空间叠加态的存在，目的是产生尽可能大的叠加态。这可以在钻石被困住或自由落体的情况下完成。除了悬浮实验的工作外，PHD项目还将包括其他非悬浮设置的工作。例如，在悬浮实验中捕获纳米钻石样品之前，将使用现有的室温共聚焦显微镜来表征纳米钻石样品。

Single nitrogen (NV-) centres in diamond have isolated electronic and nuclear spins that can store quantum information at room temperature for over one second. Using a magneto-gravitational trap to levitate nanodiamonds it is theoretically suggested that, once cooled, the nanodiamonds could be placed into a superposition of spatial states. The long-term goal is that this method will test the limits of macroscopicity for a spatial superposition state. The PhD project begins with building the magneto-gravitational trap so that consistent trapping is achieved at room temperature and pressure. The next step is implementing the vacuum and helium gas cooling systems that will take the chamber containing the trap to high vacuum and to 8K respectively. Along with the vacuum and cooling systems the PhD project will also include designing and building the required optical and electronic setups to carry out the desired measurements on the trapped nanodiamond. These include excitation and detection setups for the NV- centre photoluminescence. The PhD project will then move towards the detection and verification of the presence of a spatial superposition state, with the aim of generating as large a superposition as possible. This could be done whilst the diamond is trapped or in free fall.Alongside the work on the levitated experiment, the PhD project will include work on other non-levitated setups. For example, an existing room temperature confocal microscope will be used in order to characterise nanodiamond samples, before trapping them in the levitated experiment.