Quantum Optomechanics

物理学正在经历“第二次量子革命”，我们正在将量子力学从原子和亚原子领域推向宏观领域。在过去六年中，在使用光学技术（被称为腔光力学）对机械系统进行精确测量的显著进展的基础上，我的实验室正在努力解决机械物体在一个仅受基本量子力学考虑限制的水平上的运动。为了给人一种尺度感，我们目前的测量方法能够解决一个机械物体在飞米以下的位移，这是一个单个原子的原子核的尺度，而且一直在变得更好。此外，我们正朝着对具有真正量子特性的宏观物体进行测量的方向发展，如量子化能级、纠缠和宏观叠加态。这种在宏观尺度上进行的量子实验正开始实现一些曾经被认为只是“根底实验”的情况，比如著名的薛定谔的猫的思想实验。虽然看起来很奇特，但这些并不纯粹是学术上的探索。在人造物体中利用量子力学为量子信息和通信中的许多新量子技术打开了大门。

Physics is undergoing a “second quantum revolution,” in which we are pushing quantum mechanics from the atomic and subatomic realms up to the macroscopic realm. Building upon remarkable advances over the last six years in precision measurements of mechanical systems using optical techniques, deemed cavity optomechanics, my lab is working to resolve the motion of mechanical objects at a level that is limited only by fundamental quantum mechanical considerations. To give a sense of scale, our current measurements are capable of resolving the displacements of a mechanical object below a femtometer, which is the scale of the nucleus of a single atom - and are getting better all the time. Furthermore, we are moving towards making measurements on macroscopic objects that exhibit truly quantum properties, such as quantized energy levels, entanglement, and macroscopic superpositions of states. Such quantum experiments on macroscale objects are beginning to realize situations that were once considered only gedanken experiments, such as the famous thought experiment of Schrodinger's cat. While seemingly exotic, these are not purely academic explorations. Harnessing quantum mechanics in man-made objects opens the door to a host of new quantum technologies in quantum information and communication. Everyday, the amazing students in my lab are hard at work developing the tools and techniques to perform these quantum experiments on macroscale mechanical objects. They have built the only system in the world capable of using dimpled-tapered optical fibers (which is the most efficient technique for measuring on-chip optomechanical resonators) inside a dilution refrigerator. This system will enable cooling our mechanical devices down to 10 mK, removing thermal energy from the system to enter the quantum regime, while ensuring that our measurement has high quantum efficiency. To begin with we will passively cool our devices to as low of thermal occupation as possible, and then we will use optical techniques to push them all the way to their ground state. Once there, we will invoke nonlinear optomechanical schemes that we have been developing to perform truly quantum measurements. Our long term objectives are to observe phonon shot noise in a driven device, followed by direct measurement of quantized energy levels, so-called quantum jump spectroscopy. We are also pursuing new classes of quantum resonators based on oscillating superfluids, pulsed quantum measurements, and much more. These experiments require state-of-the-art optics, electronics, cryogenics, and nanofabrication - all marketable skills gained by my students. Working in my lab enables our personnel to find jobs at high-tech companies, start their own businesses, and overall advance Canada's knowledge-based economy.