Аннотация:A relatively simple method of overcoming the standard quantum limit in the next generation Advanced LIGO gravitational-wave detector is considered. It is based on the quantum variational measurement with a single, short (a few tens of meters) filter cavity. Estimates show that this method allows one to reduce the radiation-pressure noise at low frequencies ($<100\text{ }\text{ }\mathrm{Hz}$) to the level comparable with or smaller than the low-frequency noises of nonquantum origin (mirrors' suspension noise, mirrors' thermal noise, seismic noise, and gravity gradients fluctuations).
