Improving entanglement of assistance by local parity–time symmetric operation<xref rid="cpb_28_12_120305fn1" ref-type="fn">*</xref><fn id="cpb_28_12_120305fn1"><label>*</label><p>Project supported by China Postdoctoral Science Foundation (Grant No. 2017M622582), the Natural Science Foundation of Hunan Province of China (Grant No. 2015JJ3092), the Research Foundation of Education Bureau of Hunan Province of China (Grant No. 16B177), Applied Characteristic Disciplines in Hunan Province-Electronic Science and Technology of China, and Hunan-Provincial Key Laboratory of Photoelectric Information Integration and Optical Manufacturing Technology.</p></fn>

Improving entanglement of assistance by local parity–time symmetric operation**

Project supported by China Postdoctoral Science Foundation (Grant No. 2017M622582), the Natural Science Foundation of Hunan Province of China (Grant No. 2015JJ3092), the Research Foundation of Education Bureau of Hunan Province of China (Grant No. 16B177), Applied Characteristic Disciplines in Hunan Province-Electronic Science and Technology of China, and Hunan-Provincial Key Laboratory of Photoelectric Information Integration and Optical Manufacturing Technology.

He Zhi^{1, †}, Nie Zun-Yan¹, Wang Qiong²

(a) E^a as functions of time t and parameter θ, and (b) E^a as a function of the time t in the different θ for the W state, i.e., α=β=γ=1/3 in Eq. (7). In the figure, the time t of the PT -symmetric evolution is in units of 1/Δ E.