The Heisenberg uncertainty principle states that the position of an object cannot be known with infinite precision, as the momentum of the object would then be totally uncertain. This momentum uncertainty then leads to position uncertainty in future measurements. When continuously measuring the position of an object, this quantum effect, known as back-action, limits the achievable precision^1,2. In audio-band, interferometer-type gravitational-wave detectors, this back-action effect manifests as quantum radiation pressure noise (QRPN) and will ultimately (but does not yet) limit sensitivity³. Here, we present the use of a quantum engineered state of light to directly manipulate this quantum back-action in a system where it dominates the sensitivity in the 10–50 kHz range. We observe a reduction of 1.2 dB in the quantum back-action noise. This experiment is a crucial step in realizing QRPN reduction for future interferometric gravitational-wave detectors and improving their sensitivity.

海森堡不确定性原理指出，无法无限精确地知道物体的位置，因为物体的动量将是完全不确定的。然后，这种动量不确定性导致将来测量中的位置不确定性。当连续测量物体的位置时，这种量子效应（称为反作用）限制了可达到的精度^1,2。在音频带，干涉仪式重力波检测器中，这种反作用效应表现为量子辐射压力噪声（QRPN），最终（但尚未）限制灵敏度³。在这里，我们介绍了使用光的量子工程状态来直接操纵系统中的量子反向作用，该系统在10–50 kHz范围内支配灵敏度。我们观察到量子背向噪声降低了1.2 dB。该实验是实现减少QRPN降低未来干涉式重力波探测器并提高其灵敏度的关键步骤。