Quantum Optomechanics on Multiple Mass Scales

多质量尺度的量子光力学

• 批准号: 1068772
• 负责人: Nergis Mavalvala
• 金额: $ 95.33万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1068772&HistoricalAwards=false
• 关键词: Quantum; Optomechanics; Multiple; Mass; Scales

This award supports an experimental program to generate and characterize quantum states arising from the interaction of light with macroscopic mechanical oscillators, with the goal of furthering the understanding of the fundamental limits of quantum measurement, as well as improving the performance of interferometric gravitational-wave detectors. The two main experiments are: (i) a meter-scale interferometer with 1 gram mirrors suspended as pendulums, high circulating power, and a quantum-limited optical readout, and (ii) a centimeter-long Fabry-Perot cavity with a cryogenically cooled 250 nanogram cantilevered micromirror. The objectives of these experiments are: (1) Direct observation quantum radiation pressure (backaction) noise; (2) Observation and manipulation of optomechanically induced transparency that arises when optomechanical coupling introduces sufficient optical rigidity to renormalize the dressed mechanical states into optically-bright and optically-dark modes of motion; (3) Observation of ponderomotive squeezing; (4) Observation of ground state cooling of a macroscopic object; (5) Reaching and surpassing the free-particle Standard Quantum Limit; (6) Observation of quantum entanglement, arising from radiation pressure induced coupling of the motion of the mirror and the quantum radiation field. None of these phenomena have been observed experimentally to date. The main purpose of this program is to further the understanding of radiation-pressure-dominated interferometers, an important feature of future gravitational-wave detectors. Equally attractive is the prospect of exploring the fundamental physics of quantum correlations due to optical-mechanical couplings in a macroscopic mechanical oscillator system.Interferometric gravitational wave detectors, such as those of the Laser Interferometer Gravitational-wave Observatory (LIGO), are seeking to detect gravitational waves emitted by violent cosmic events such as supernova explosions and collisions of neutron stars and black holes. Since gravitational waves are completely distinct from electromagnetic radiation, direct detection of gravitational waves is expected to open a new window into the Universe and provide opportunities to study cosmic phenomena that are "invisible" using light alone. Gravitational waves from astrophysical sources cause microscopic distortions of spacetime that can be measured by an interferometer whose mirrors are suspended as pendulums to isolate them from all other effects beside the gravitational wave. The changes in arm length, typically of order 1/1000 the size of a proton, are detected by very precise measurement of the interference pattern of the laser light reflected from each 4 kilometer long arm of the interferometer. Quantum fluctuations of the light arising from the discrete nature of photons limit the sensitivity of gravitational wave detectors. This so-called shot noise, due to the random quantum fluctuations of the light, limits the precision with which the interference pattern, and hence the gravitational wave signal, can be measured. Similarly, radiation pressure noise limits the sensitivity due to the interferometer mirrors being "kicked" by the fluctuating momentum of the photons that is transferred to the mirrors when the laser light reflects from them. Studying ways to characterize and circumvent this noise limit is essential to making further improvements in sensitivity of gravitational wave detectors and also allows for the study of fundamental quantum effects, such as squeezing and entanglement, in macroscopic mechanical systems. The broader impact of this research program lies in its scientific and its personnel diversity. The scientific diversity arises from the necessarily cross-disciplinary nature of the proposed research: it combines the techniques and formalism of quantum optics and quantum measurement theory with gravitational wave detection. The personnel diversity is the outcome of aggressive recruitment of women and minority students by the PI (herself a member of minority groups), through her own efforts as well as those of the outreach programs of the LIGO Laboratory and MIT. In addition, the sub-quantum-noise-limit measurements are popular with students and generate considerable enthusiasm with the public as well. The proposed experiments share common technologies with quantum information, quantum control, and mesoscopic condensed matter physics (nano- and micro-mechanical oscillators).

该奖项支持一项实验计划，以产生和表征光与宏观机械振荡器相互作用产生的量子态，其目标是进一步理解量子测量的基本限制，以及提高干涉引力波探测器的性能。两个主要实验是：（i）米级干涉仪，其具有1克的反射镜悬挂为棱镜、高循环功率和量子限制的光学读出，以及（ii）厘米长的法布里-珀罗腔，其具有低温冷却的250毫微克的悬臂梁。这些实验的目的是：（1）直接观测量子辐射压力（2）光机械耦合引入足够的光学刚性以将修饰的力学态重整为光学亮和光学暗运动模式时产生的光机械诱导透明的观察和操纵;（3）有质动力压缩的观察;（4）宏观物体基态冷却的观测;（5）达到和超过自由粒子标准量子极限;（6）量子纠缠的观测，由辐射压力引起的镜子和量子辐射场运动的耦合。迄今为止，这些现象都没有在实验中观察到。该计划的主要目的是进一步了解辐射压力主导的干涉仪，这是未来引力波探测器的一个重要特征。同样吸引人的是探索宏观力学振荡系统中由于光-机耦合而产生的量子关联的基本物理学的前景。干涉引力波探测器，如激光干涉引力波天文台（LIGO）的那些，正在寻求探测由剧烈的宇宙事件（如超新星爆炸和中子星与黑洞的碰撞）发射的引力波。由于引力波与电磁辐射完全不同，直接探测引力波有望打开一扇了解宇宙的新窗口，并为研究仅使用光“不可见”的宇宙现象提供机会。来自天体物理学源的引力波会引起时空的微观扭曲，这种扭曲可以通过干涉仪来测量，干涉仪的反射镜被悬挂在望远镜上，以将它们与引力波以外的所有其他效应隔离开来。臂长的变化，通常是质子大小的1/1000，通过非常精确地测量从干涉仪的每个4公里长的臂反射的激光的干涉图案来检测。由光子的离散性质引起的光的量子涨落限制了引力波探测器的灵敏度。这种所谓的散粒噪声，由于光的随机量子波动，限制了干涉图样的精度，从而限制了引力波信号的测量精度。类似地，辐射压力噪声限制了灵敏度，这是由于当激光从干涉仪反射镜反射时，干涉仪反射镜被转移到反射镜的光子的波动动量“踢”。研究表征和规避这种噪声限制的方法对于进一步提高引力波探测器的灵敏度至关重要，并且还可以研究宏观力学系统中的基本量子效应，如压缩和纠缠。 这项研究计划的更广泛的影响在于其科学和人员的多样性。科学的多样性源于所提出的研究的必然跨学科性质：它将量子光学和量子测量理论的技术和形式与引力波探测相结合。人员的多样性是PI（她自己也是少数群体的成员）通过自己的努力以及LIGO实验室和麻省理工学院的推广计划积极招募女性和少数民族学生的结果。此外，亚量子噪声极限测量受到学生的欢迎，也引起了公众的极大热情。拟议的实验与量子信息，量子控制和介观凝聚态物理学（纳米和微机械振荡器）共享共同的技术。