Optomechanical ground-state cooling

主讲人 (Speaker): 
李勇  特聘研究员
主讲人单位 (Speaker's Institute): 
北京计算科学研究中心
邀请人 (Invited by): 
李朝红
时间 (Time): 
星期四, 2017/04/20 - 15:30 to 17:00
地点 (Location): 
珠海校区行政楼八层天琴引力物理研究中心大会议室
摘要 (Abstract): 

 Conventional optomechanical ground-state cooling requires the condition of resolved sideband where the mechanical frequency is larger than the optical decay rate. We propose to cool a mechanical resonator close to its ground state via an electromagnetically-induced-transparency-like cooling mechanism in a double-cavity optomechanical system, where an additional cavity couples to the original one in the standard optomechanical system. The mechanical resonator can be cooled close to its ground state in such a model even when the original resolved sideband condition is not fulfilled, since the effective sideband condition is fulfilled by effectively suppressing the optical decay rate. We also achieve the mechanical ground-state cooling in a membrane-in-themiddle optomechanical system where both the x-dependent and x2-dependent (quadratic) optomechanical couplings exist (x is the mechanical displacement). Here the quadratic coupling provides an additional mechanical potential so that the effective mechanical frequency can be modified. That is, the effective sideband condition can be fulfilled by effectively enlarging the mechanical frequency though the original resolved sideband condition is not fulfilled, and thus the ground-state cooling can be achieved with the usual x-dependent optomechanical coupling.

主讲人简介 (Speaker's CV): 
李勇,男,博士,北京计算科学研究中心研究员,博士生导师。1999年毕业于华中理工大学 (现华中科技大学),2001年于中国科学院武汉物理与数学研究所获硕士学位,2004年于 中国科学院理论物理研究所获得博士学位。之后先后在中国科学院理论物理交叉研究中心、 瑞士巴塞尔大学和香港大学做博士后研究。2010年起任北京计算科学研究中心研究员, 2014年获得国家自然科学基金委优秀青年基金。研究领域主要包括量子光学、基于光与物质 相互作用的量子物理与量子信息,近年来主要从事基于微纳机械振子的量子光力学方面的研 究。在国内外学术刊物上共发表 SCI 论文70余篇,其中3篇发表在Phys. Rev. Lett.上。 主要研究兴趣:  Quantum optics; Optomechanics; Micro-/nano - mechanical resonator