AI 中文总结
该研究针对KAGRA后O5升级，对比多种量子噪声抑制方案，发现FC方案性能优异，可提升BNS探测范围与率，EPR方案更适用于重双天体系统探测。
AI 中文摘要
量子噪声源于电磁场的量子化，一直是当前引力波（GW）探测器的限制噪声源，压缩真空可改变量子涨落并已被常规使用。为降低量子噪声，当前方案是将压缩真空与失谐过耦合光学腔（滤波腔）结合，以实现频率依赖压缩（FDS）。对GW信号的灵敏度可分解为噪声预算，根据探测器配置，量子噪声以外的噪声源贡献可能显著，特别是多级摆的悬挂噪声是量子噪声抑制设计的关键因素。在KAGRA后O5背景下，我们对比了多种量子噪声抑制方案：频率独立压缩（FIS）、带滤波腔（FC）的FDS、带振幅滤波腔（AFC）的FDS、带频率依赖分束器（FDBS）的FDS以及EPR方案。结果发现，FC方案在所有频率下均优于AFC和FDBS方案；当低频噪声以经典噪声为主时，FIS方案能给出最大的双中子星（BNS）探测范围，而当低频噪声转为以量子噪声为主时，FC方案能给出最大的BNS探测范围。优化后的滤波腔参数可大幅提升BNS探测范围，与使用FIS方案相比，85米长的滤波腔可使探测率至少提升23%。一旦构建出参数优化的滤波腔，微调其失谐量可完全补偿臂功率（从一半到满设计值）的变化以及不同的腔内损耗条件。EPR方案对重双天体系统的探测表现最佳。
英文摘要
Quantum noise, arising from the quantisation of electromagnetic field, has been a limiting noise source for current gravitational wave (GW) detectors. Squeezed vacuum modifies quantum fluctuations and has been routinely employed. To reduce quantum noise, the current solution is to combine squeezed vacuum with a detuned over-coupled optical cavity (filter cavity) to achieve frequency-dependent squeezing (FDS). The sensitivity to GW signals can be decomposed into a noise budget. Depending on the detector configuration, the contribution from noise sources other than quantum noise can be significant. In particular, suspension noise from multi-stage pendulums is a key factor in quantum-noise reduction design. In the context of KAGRA post-O5, we have compared quantum noise reduction schemes, frequency-independent squeezing (FIS), FDS with a filter cavity (FC), FDS with an amplitude filter cavity (AFC), FDS with a frequency-dependent beam splitter (FDBS) and EPR scheme. The FC scheme was found to outperform the AFC and FDBS schemes at all frequencies. It was found that FIS scheme gives the largest Binary Neutron Star (BNS) range when low frequency noise is dominated by classical noise, while the FC scheme gives the largest BNS range when low-frequency noise becomes dominated by quantum noise. Optimised filter cavity parameters could substantially improve the BNS range. This would allow at least 23% increase in the detection rate for an 85 m filter cavity, compared with using FIS scheme. Once a filter cavity is constructed with optimised parameters, refining its detuning can fully compensate for the variations in arm power (from half to full design value) and for different intra-cavity loss conditions. The EPR scheme performs best for the detection of heavy binary systems.
