The recent series of gravitational-wave detections by the Advanced LIGO and Advanced Virgo observatories have launched the new field of gravitational-wave astronomy. As the sensitivity of gravitational-wave detectors is limited by the quantum noise of light, concepts from quantum metrology have been adapted to increase the observational range. Since 2010, squeezed light with reduced quantum noise has been used to achieve improved sensitivity at signal frequencies above 100 Hz. However, 100-m-long optical filter resonators would be required to also improve the sensitivity at lower frequencies, adding significant cost and complexity. Here, we report a proof-of-principle set-up of an alternative concept that achieves the broadband noise reduction by using Einstein–Podolsky–Rosen entangled states instead. We show that the desired sensitivity improvement can then be obtained with the signal recycling resonator that is already part of current observatories, providing a viable alternative to high-cost filter cavities.

Advanced LIGO 和 Advanced Virgo 天文台最近进行的一系列引力波探测开创了引力波天文学的新领域。由于引力波探测器的灵敏度受到光量子噪声的限制，量子计量学的概念已被采用以增加观测范围。自 2010 年以来，已使用具有降低量子噪声的压缩光来提高信号频率高于 100 Hz 的灵敏度。然而，还需要 100 米长的光学滤波器谐振器来提高较低频率下的灵敏度，从而显着增加成本和复杂性。在这里，我们报告了另一种概念的原理验证设置，该概念通过使用爱因斯坦-波多尔斯基-罗森纠缠态来实现宽带噪声降低。我们表明，可以通过信号循环谐振器获得所需的灵敏度改进，该信号循环谐振器已经是当前天文台的一部分，为高成本滤波器腔提供了可行的替代方案。