Quantum estimation of detection efficiency with no-knowledge quantum feedback<xref rid="cpb_27_6_060303_fn1" ref-type="fn">*</xref> <fn id="cpb_27_6_060303_fn1"> <label>*</label> <p>Project supported by the National Natural Science Foundation of China (Grant No. 11747008) and the Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No. 2016GXNSFBA380227).</p> </fn>

Quantum estimation of detection efficiency with no-knowledge quantum feedback* *

Project supported by the National Natural Science Foundation of China (Grant No. 11747008) and the Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No. 2016GXNSFBA380227).

Xie Dong^†, Xu Chunling

(color online) Diagram of the exact minimum precision and approximate analytical precision Nδη² changing with the detection efficiency η. The exact minimum precision comes from numerical calculation. The approximate analytical precision comes from Eq. (27); it shows that the approximate analytical precision is close to the exact precision.