Title: Optical levitation and quantum spin-optomechanics of levitated nanodiamonds
Speaker: Tongcang Li Purdue University
Time: 2016-06-14 10:00-2016-06-14 11:30
Venue: MMW-S327

Abstract:

Optomechanical systems, such as LIGO (Laser Interferometer Gravitational-Wave Observatory), are extremely sensitive devices that have broad applications. Once cooled to the quantum regime, they will allow us to study macroscopic quantum mechanics at unprecedented size and mass scales. In this talk, I will first introduce basic concepts in optomechanics. I will then focus on optically levitated dielectric particles. With a glass microsphere levitated in air, we have measured the instantaneous velocity of Brownian motion, a task that was said to be impossible by Albert Einstein in 1907. In vacuum, we have cooled the center-of-mass motion of a levitated microsphere from room temperature to about 1.5mK. We are currently working on spin-optomechanics of levitated nanodiamonds with built-in nitrogen-vacancy (NV) centers, with the goal to create large quantum spatial superposition states of nanodiamonds using the spin-optomechanical coupling. This will enable the development of nanoparticle matter-wave interferometry. We have demonstrated electron spin control of levitated nanodiamonds and observed their torsional vibration.



Short Bio:

李统藏 (Tongcang Li),2004年本科毕业于中国科学技术大学,2011年在美国德克萨斯大学奥斯汀分校获得博士学位。2011-2014年在美国加州大学伯克利分校做博士后。2014年至今在美国普渡大学“物理和天文系”及“电子工程和计算机系”任双聘助理教授,博士生导师。在Science, Nature Physics, Nature Communications, Physical Review Letters 等杂志发表论文二十余篇,在Springer出版专著一部。李统藏在2010年和合作者用激光光镊首次实验测量了悬浮粒子布朗运动的瞬时速度,完成了这个爱因斯坦在一百多年前认为是不可能完成的任务。该工作被Science杂志推荐为高中及大学教学内容。2012年和合作者首次提出利用超冷束缚离子实现时空晶体的实验方案,被Nature杂志选为研究亮点, 并被Discovery传播公司拍摄成纪录片。2015年和合作者提出活体微生物的量子态叠加,纠缠和隐形传态方案, 引起学术界和媒体的广泛关注,并被收入在《福布斯》发表的《宇宙的十大量子现实》。李统藏在2016年获得了美国国家科学基金会杰出青年教授奖。他还曾获得Springer博士论文奖,中国“国家优秀自费留学生奖学金”,美国光学学会基金会“杰·贝内特纪念奖”等奖项。