Quantum metrology with a non-Markovian qubit system<xref rid="cpb_27_12_120301fn1" ref-type="fn">*</xref><fn id="cpb_27_12_120301fn1"><label>*</label><p>Projects supported by the Natural Science Foundation of Guangdong Province, China (Grant No. 2015A030310354), the Science Foundation for Enhancing School with Innovation of Guangdong Ocean University (Grant Nos. GDOU2017052504 and GDOU2015050207), the Foundation of Excellent-Young-Backbone Teacher of Guangdong Ocean University (Grant No. HDYQ2017005), and the Fund of University Student Innovation and Entrepreneurship Team of Guangdong Ocean University (Grant No. CCTD201823).</p></fn>

Quantum metrology with a non-Markovian qubit system**

Projects supported by the Natural Science Foundation of Guangdong Province, China (Grant No. 2015A030310354), the Science Foundation for Enhancing School with Innovation of Guangdong Ocean University (Grant Nos. GDOU2017052504 and GDOU2015050207), the Foundation of Excellent-Young-Backbone Teacher of Guangdong Ocean University (Grant No. HDYQ2017005), and the Fund of University Student Innovation and Entrepreneurship Team of Guangdong Ocean University (Grant No. CCTD201823).

Huang Jiang, Shi Wen-Qing^†, Xie Yu-Ping, Xu Guo-Bao^‡, Wu Hui-Xian

(color online) QFI is plotted against the dimensionless quantities γ₀t and Δ/γ₀ for the optimal output state . (a) The dotted line is the QFI in terms of γ₀t in the Markovian regime with λ = 5γ₀ and Δ = 0. The other three line are the QFI in terms of γ₀t in the non-Markovian regime with λ = 0.05γ₀ and Δ = 0 (the blue line), Δ = 0.5γ₀ (the green line) and Δ = 1.5γ₀ (the red line). (b) QFI in terms of Δ/γ₀ for different values of λ with γ₀t = 10.