Improving the sensitivity of gravitational-wave detectors

自2015年秋季开始第一次观测以来，高级LIGO和处女座已经直接探测到了黑洞和中子星碰撞产生的引力波，从而为天文学带来了一台新的仪器。这是通过他们对微小变化(在100赫兹时小于10^-19m！)的测量来实现的。在两面相隔很大的镜子之间的距离。先进的LIGO激光干涉仪已经是世界上最精确的测量设备，但在进一步改进干涉仪以提高信噪比和引力波探测速度的道路上仍然存在许多挑战。由光的量子性质等基本物理和技术来源(如用于控制干涉仪无数自由度的不完美传感器)产生的噪声需要巧妙的解决方案，以突破技术的极限。对于博士生来说，有几个可能的研究方向。项目可能包括开发和测试新的干涉读数计划，研究新的激光波长，设计和建造倾斜不敏感的惯性传感器以改善地震隔离，改进压缩光与干涉仪的集成，设计新的光学布局并制作原型以提高目标频率的灵敏度，为第三代干涉仪(如爱因斯坦望远镜)的控制拓扑建模，以及利用精密干涉测量为基础物理实验做出贡献。博士生将获得高精度光学实验和复杂实验系统的噪声分析方面的技能，同时为引力波天文学的萌芽领域做出贡献。

Since the start of their first observing runs in fall 2015, Advanced LIGO and Virgo have made direct detections of gravitational waves created by the collisions of black holes and of neutron stars, thus bringing to life a new instrument for astronomy. This is accomplished through their measurements of infinitesimal changes (less than 10^-19 m at 100 Hz!) in the distance between two largely separated mirrors. The Advanced LIGO laser interferometers are already the most precise measurement devices in the world, but there nonetheless remain many challenges along the path to further improve the interferometers in order to increase the signal-to-noise ratio and rate of gravitational wave detections. Noise resulting from fundamental physics such as the quantum nature of light and from technical sources such as the imperfect sensors used for controlling the interferometer's myriad degrees of freedom require clever solutions that push the limits of technology. There are several possible research directions for a PhD student. Projects could include developing and testing new interferometric readout schemes, researching new laser wavelengths, designing and building tilt-insensitive inertial sensors for improved seismic isolation, improving the integration of squeezed light to the interferometers, designing and prototyping new optical layouts for sensitivity improvement at targeted frequencies, modelling control topologies for third generation interferometers such as the Einstein Telescope, and contributing to fundamental physics experiments using precision interferometry. The PhD student will gain skills in high-precision optical experiments and noise analyses of complex experimental systems, all the while contributing to the budding field of gravitational-wave astronomy.