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) Schematic diagram for a measurement-based feedback control protocol. Information about the system is extracted by monitoring the decoherence channel L. The feedback Hamiltonian is applied to the system according to the homodyne current I(t) from the homodyne detection. Here, η denotes the detection efficiency.