Optimal control of quantum state preparation and entanglement creation in two-qubit quantum system with bounded amplitude.

We consider the optimal control problem in a two-qubit system with bounded amplitude. Two cases are studied: quantum state preparation and entanglement creation. Cost functions, fidelity and concurrence, are optimized over bang-off controls for various values of the total duration, respectively. For quantum state preparation problem, three critical time points are determined accurately, and optimal controls are estimated. A better estimation of the quantum speed limit is obtained, so is the time-optimal control. For entanglement creation problem, two critical time points are determined, one of them is the minimal time to achieve maximal entanglement (unit concurrence) starting from the product state. In addition, the comparisons between bang-off and chopped random basis (CRAB) are made.

[Seroepidemiology of varicella among the healthy population aged 1-19 years in Harbin, China].

OBJECTIVE: To investigate the level of IgG antibody to varicella in the healthy population aged 1-19 years in Harbin, China. METHODS: Random sampling was performed to select 1 203 healthy individuals aged 1-19 years in Harbin. According to age, they were divided into ≥1 years group (n=240), ≥4 years group (n=396), ≥7 years group (n=364) and 14-19 years group (n=203). Enzyme-linked immunosorbent assay was used to measure the concentration of varicella-zoster virus (VZV)-IgG antibody in serum, and a concentration of VZV-IgG antibody of ≥100 mIU/mL was considered positive, suggesting that the subject had the ability to resist VZV infection. RESULTS: The overall positive rate of VZV-IgG antibody was 71.49% (860/1 203), and the concentration of VZV-IgG antibody was 447±17 mIU/mL. The concentration of VZV-IgG antibody tended to increase with age (P<0.05). The positive rate of VZV-IgG antibody in the urban population was significantly higher than that in the rural population (P<0.05). There was significant difference in the positive rate of VZV-IgG antibody between the populations with different doses of varicella vaccination (P<0.05), and the population with 2 doses of vaccination had the highest positive rate of VZV-IgG antibody. There was a significant difference in the concentration of VZV-IgG antibody between the populations with different medical histories (P<0.05), and the population with a past history of varicella had the highest concentration. CONCLUSIONS: Among the healthy population aged 1-19 years in Harbin, there is a significant difference in the level of VZV-IgG antibody between the urban and rural populations, as well as between different age groups. Varicella vaccination should be strengthened in areas with a low vaccination rate and the population aged <14 years.

Local unitary classification of arbitrary dimensional multipartite pure states.

We propose a practical entanglement classification scheme for general multipartite pure states in arbitrary dimensions under local unitary equivalence by exploiting the high order singular value decomposition technique and local symmetries of the states. By virtue of this scheme, the method of determining the local unitary equivalence of n-qubit states proposed by Kraus is extended to the case for arbitrary dimensional multipartite states.

[Study on technological characters of anaerobic-aerobic bioreactor landfill].

A technology of anaerobic-aerobic landfill bioreactor aimed at reusing landfill site is studied, and it's based on landfill bioreactor technology. A set of stimulating equipment is designed, and the technology characters are studied. In the anaerobic period, technological conditions are controlled by the means of leachate recirculation. The main experimental results are: pH, R1 rises to 6.7 - 7.8 in 6 weeks, and R2 is under 6.8 in 17 weeks; COD concentration of leachate, R1 declines to 10 617 mg/L in 13 weeks, while R2 rises to 60 000 mg/L in 5 weeks, and keeps stabilization in long time; the cumulating methane production, R1 reaches 44% in 8 weeks, while R2 almost cannot produce methane. The stabilization can be evaluated by pH of leachate, COD and BOD5/COD decreasing ratio, and cumulating methane production. They are main evidences to transform anaerobic period to aerobic period. In the aerobic period, odor and moisture are reduced by the means of aeration. The main experimental results are: ammonia concentration reduces to 1.16 mg/m3 in 19 days, and the odor concentration reduces to 19 in 23 days; the moisture of the wastes reduces to 26% in 14 days. The technological indexes to evaluate finishing of this period can be determined by the ultimately purpose of exploited wastes. Numerical modeling has been researched with the use of experimental data. The succession of microbes in the anaerobic-aerobic course is studied by RISA (ribosomal intergenic spacer analysis) analysis. There are 4 preponderant groups in this course, and some facultative anaerobes play important roles in the transition of anaerobic period to aerobic period.