Quantum Optics and Optomechanics: From Fundamental Tests To Quantum Tools of the Future

该奖项支持相对论和相对论天体物理学的研究，它解决了NSF“宇宙之窗”大构想的优先领域。量子力学是物理学的一个分支，用来解释微观的原子和亚原子尺度的世界。量子行为本质上不同于人类对宏观世界的体验。量子系统的特征包括基本的不确定性和纠缠。这些量子现象可以用来对物理量进行更精确的测量。例如，量子工程使科学家能够以亚原子计的精度测量引力波探测器（GWD）反射镜之间的距离。这个项目属于一个正在进行的实验项目，旨在开发量子系统来探测基本的量子现象，以及应用于精确的量子噪声限制测量。研究小组的重点是理解和操纵量子噪声，这对于提高量子噪声的性能，以及在宏观尺度上探索压缩和纠缠等基本量子现象都很重要。多样性是拟议工作在科学和人员方面的基础。科学多样性源于拟议研究的必然的跨学科性质：它结合了量子光学、光力学和量子测量科学与GWDs的技术和形式。人员的多样性是PI（她自己也是多个少数民族团体的成员）通过她自己的努力以及LIGO实验室和麻省理工学院的外展项目有意招募女性和少数民族学生的结果。此外，量子科学在学生中很受欢迎（十几篇博士和本科论文都来自于这个研究项目），并且在公众中也产生了相当大的热情。提出的实验方案旨在研究量子涨落的多种表现形式及其对光学测量和宏观物体运动的影响。这可以测试量子力学的基本原理，也可以在光学传感和精确力和位置测量的量子技术方面取得进展。该小组正在进行两项利用光和机械运动的量子涨落的实验。一个实验探索光力学系统中的量子效应，其中光和机械运动之间的辐射压力相互作用被设计为主导。在这个研究项目中，利用纳米级到千克级的机械振荡器进行腔光力学实验，用光和机械运动之间的相互作用来产生和操纵量子态。这些实验成功地展示了宏观反射镜的光学冷却和捕获技术，使直接观察和逃避量子辐射压力（反作用）噪声成为先进LIGO中主要的限制噪声源，并产生宽带光力学压缩作为一种有前途的替代方法，以产生适合未来GW探测器的压缩光态。该光力学平台的一个重要特点是，它被设计用于实现非低温预冷的宏观机械振子的量子态。下一个目标是观察有条件压缩的机械状态，从而创造出作为室温光力学平台一部分的镜子量子态。另一项实验则推进了精确测量的压缩光技术。具体来说，该小组正在研究一种基于非线性光学材料的紧凑型压缩光源，该光源将用于研究和减少线性光学放大过程中的量子噪声，并将成为最终实现片上压缩器的垫脚石。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award supports research in relativity and relativistic astrophysics, and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. Quantum mechanics is the branch of physics used to explain the microscopic atomic and subatomic scale world. Quantum behavior is inherently different than the human experience of the macroscopic world. Hallmarks of quantum systems include fundamental uncertainty and entanglement. These quantum phenomena can be exploited to make more precise measurements of physical quantities. For example, quantum engineering allows scientists to measure the distance between the mirrors of a gravitational wave detector (GWD) with sub-attometer precision. This project pertains to an ongoing experimental program to develop quantum systems to probe fundamental quantum phenomena, as well as for applications to precision quantum noise-limited measurement. The emphasis of the research group is understanding and manipulating quantum noise in GWDs, which is important both for improved performance of GWDs, and also for probing fundamental quantum phenomena such as squeezing and entanglement on macroscopic scales. Diversity underpins the scientific and personnel aspects of the proposed work. The scientific diversity arises from the necessarily cross-disciplinary nature of the proposed research: it combines the techniques and formalism of quantum optics, optomechanics, and quantum measurement science with GWDs. The personnel diversity is the outcome of deliberate recruitment of women and minority students by the PI (herself a member of multiple minority groups), through her own efforts as well as those of the outreach programs of the LIGO Laboratory and MIT. Additionally, quantum science is popular with students (over a dozen Ph.D. and undergraduate theses have derived from this research program), and generates considerable enthusiasm with the public as well.The proposed experimental program aims to study multiple manifestations of quantum fluctuations and their effect on optical measurements and on motion of macroscopic objects. This allows for testing fundamental tenets of quantum mechanics, and also for making advances in quantum technologies for optical sensing and precision force and position measurement. The group is carrying out two experiments that exploit quantum fluctuations of light and mechanical motion. One experiment explores quantum effects in optomechanical systems where the radiation-pressure interaction between light and mechanical motion is engineered to dominate. Cavity optomechanics experiments with mechanical oscillators spanning nanogram- to kilogram-scales have featured prominently in this research program, where the interaction between light and mechanical motion is used to generate and manipulate quantum states. These experiments have successfully demonstrated optical cooling and trapping techniques for macroscopic mirrors, have enabled direct observation and evasion of quantum radiation pressure (backaction) noise that is a major limiting noise source in Advanced LIGO, and generation of broadband optomechanical squeezing as a promising alternative method for generating squeezed states of light suitable for future GW detectors. An important feature of this optomechanics platform is that it is designed to achieve the quantum regime with macroscopic mechanical oscillators that are not cryogenically pre-cooled. The immediate next goals are to observe conditionally squeezed mechanical states on the path toward creating quantum states of mirrors that are part of a room temperature optomechanics platform. The other experiment advances squeezed light technology for precision measurement. Specifically, the group is working on a compact squeezed light source based on nonlinear optical materials that is to be used to study and reduce quantum noise in linear optical amplification processes, and will be a steppingstone to an eventual squeezer-on-a-chip.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.