Majorana tunneling in a one-dimensional wire with non-Hermitian double quantum dots

The combination of non-Hermitian physics and Majorana fermions can give rise to new effects in quantum transport systems. In this work, we investigate the interplay of PT-symmetric complex potentials, Majorana tunneling and interdot tunneling in a non-Hermitian double quantum dots system. It is found that in the weak-coupling regime the Majorana tunneling has pronounced effects on the transport properties of such a system, manifested as splitting of the single peak into three and a reduced 1/4 peak in the transmission function. In the presence of the PT-symmetric complex potentials and interdot tunneling, the 1/4 central peak is robust against them, while the two side peaks are tuned by them. The interdot tunneling only induces asymmetry, instead of moving the conductance peak, due to the robustness of the Majorana modes. There is an exceptional point induced by the union of Majorana tunneling and interdot tunneling. With increased PT-symmetric complex potentials, the two side peaks will move towards each other. When the exceptional point is passed through, these two side peaks will disappear. In the strong-coupling regime, the Majorana fermion induces a 1/4 conductance dip instead of the three-peak structure. PT-symmetric complex potentials induce two conductance dips pinned at the exceptional point. These effects should be accessible in experiments.

Heteronuclear Magnetisms with Ultracold Spinor Bosonic Gases in Optical Lattices

Motivated by recent realizations of spin-1 NaRb mixtures in the experiments[Phys.Rev.Lett.114,255301(2015);Phys.Rev.Lett.128,223201(2022)],we investigate heteronuclear magnetism in the Mott-insulating regime.Different from the identical mixtures where the boson statistics only admits even parity states from angular momentum composition,for heteronuclear atoms in principle all angular momentum states are allowed,which can give rise to new magnetic phases.While various magnetic phases can be developed over these degenerate spaces,the concrete symmetry breaking phases depend on not only the degree of degeneracy but also the competitions from many-body interactions.We unveil these rich phases using the bosonic dynamical mean-field theory approach.These phases are characterized by various orders,including spontaneous magnetization order,spin magnitude order,singlet pairing order,and nematic order,which may coexist specially in the regime with odd parity.Finally we address the possible parameter regimes for observing these spin-ordered Mott phases.

Streett自动机确定化工具

自动机的确定化是将非确定性自动机转换为接收相同语言的确定性自动机,是自动机理论的基本问题之一.ω自动机的确定化是诸多逻辑,如SnS,CTL*,μ演算等,判定过程的基础,同时也是解决无限博弈求解问题的关键,因此对ω自动机确定化的研究具有重要意义.主要关注一类ω自动机——Streett自动机的确定化.非确定性Streett自动机可以转换为等价的确定性Rabin或Parity自动机,在前期工作中已经分别得到了状态复杂度最优以及渐进最优算法,为了验证提出的算法的实际效果,也为了形象地展示确定化过程,开发一款支持Streett自动机确定化的工具是必要的.首先介绍4种不同的Streett确定化结构:μ-Safra tree和H-Safra tree(最优)将Streett确定化为Rabin自动机,compact Streett Safra tree和LIR-H-Safra tree(渐进最优)将Streett确定化为Parity自动机;然后,根据Streett确定化算法,基于开源工具GOAL(graphical tool for omega-automata and logics),实现了Streett确定化工具NS2DR&PT,以支持上述4种结构;最后,通过随机生成100个Streett自动机,构造相应的测试集,进行对比实验,结果表明各结构状态复杂度的实际效果与理论论证一致,此外,对运行效率也进行了比较分析.

Effects of dietary coenzyme Q10 supplementation during gestation on the embryonic survival and reproductive performance of high‑parity sows

Background Fertility declines in high-parity sows.This study investigated whether parity-dependent declines in embryonic survival and reproductive performance could be restored by dietary coenzyme Q10(CoQ10)supplementation.Methods Two experiments were performed.In Exp.1,30 young sows that had completed their 2nd parity and 30 high-parity sows that had completed their 10^(th)parity,were fed either a control diet(CON)or a CON diet supple-mented with 1 g/kg CoQ10(+CoQ10)from mating until slaughter at day 28 of gestation.In Exp.2,a total of 314 post-weaning sows with two to nine parities were fed the CON or+CoQ10 diets from mating throughout gestation.Results In Exp.1,both young and high-parity sows had a similar number of corpora lutea,but high-parity sows had lower plasma CoQ10 concentrations,down-regulated genes involved with de novo CoQ10 synthesis in the endome-trium tissues,and greater levels of oxidative stress markers in plasma and endometrium tissues.High-parity sows had fewer total embryos and alive embryos,lower embryonic survival,and greater embryo mortality than young sows.Dietary CoQ10 supplementation increased the number of live embryos and the embryonic survival rate to levels simi-lar to those of young sows,as well as lowering the levels of oxidative stress markers.In Exp.2,sows showed a parity-dependent decline in plasma CoQ10 levels,and sows with more than four parities showed a progressive decline in the number of total births,live births,and piglets born effective.Dietary supplementation with CoQ10 increased the number of total births,live births,and born effective,and decreased the intra-litter covariation coefficients and the percentage of sows requiring farrowing assistance during parturition.Conclusions Dietary CoQ10 supplementation can improve the embryonic survival and reproductive performance of gestating sows with high parity,probably by improving the development of uterine function.

RAIM算法研究

用户自主式完备性监测 RAIM算法是广域差分 GPS的关键和核心技术之一。在已有 RAIM算法的基础上 ,讨论了粗差探测和定位的方法 ,并给出了 Parity方法中剔除多个粗差的算法 ,最后用 ' 99南海实测数据进行了验证。

文化壁垒、政府价值取向与实际汇率波动

通过博弈分析发现,在商品和生产要素自由流通、两国市场规模相同、完全信息和产品同质假定下,两国居民对待进口产品的态度不同,或两国政府在经济增长速度和保障就业水平两个目标上的偏好不同,将导致两国产品具有不同的价格水平,进而导致实际汇率偏离购买力平价。消费文化和政府经济调控目标差异对实际汇率有一定影响。

PT对称光晶格中的缺陷暗孤子

数值研究了实部具有缺陷的parity-time(PT)对称光晶格中的缺陷暗孤子。当衍射与自散焦非线性效应平衡时,暗孤子能够被获得;当自散焦介质中的PT对称光晶格实都被附加一个缺陷后,缺陷暗孤子也能够被获得。数值结果显示:缺陷暗孤子可以在很大参数范围内存在并能稳定传播;PT对称光晶格实部附加的缺陷强度有一最大值,超过此值缺陷暗孤子不存在;PT对称光晶格的虚部振幅对缺陷暗孤子的稳定性有影响。

GPS自主完整性监测算法研究

完整性检测是GPS的重要技术问题之一,传统RAIM算法有最小二乘法和Parity法等,大多在分离多颗故障卫星时的效果不佳,本文在对卫星导航系统中现有RAIM算法进行研究的基础上,讨论了故障卫星的探测与分离方法,提出了一种将传统算法有效结合的新算法,该算法能有效探测和分离多颗故障卫星。通过对各种不同的算法进行仿真,并对仿真结果进行对比,证明该算法具有能准确分离故障卫星和实时性强等优点。

Effect of Cesarean Section on the Severity of Postpartum Hemorrhage in Chinese Women： The Shanxi Study

Postpartum hemorrhage （PPH） is one of the most adverse obstetric outcomes. Our aim is to detect the risks of multilevel PPH in different cesarean section （CS） groups [including nulliparous CS with indications, nulliparous CS without indications, repeat cesarean （RC）, vaginal birth after cesarean （VBAC）, cesarean after vaginal birth （CAVB）]. We conducted a retrospective cohort study, and the data on 127 145 women collected from January 2014 to May 2016 and from 35 tertiary hospitals in Shanxi province, China, were reviewed. Based on the measuring results of PPH, an ordered logistic regression model was used to analyze the adjusted PPH risks for each of the CS groups, and comparisons were drawn between them. Finally, a total of 99 066 nulliparous （77.92%） and 28 079 multiparous （22.08%） women were observed. The number of CS cases was 61 117, and the rate for CS was 48.07%. A total of 10 029 women did not show indications for CS and accounted for 16.41% of the CS parturient, whereas 9103 women underwent a repeated cesarean, with a CS frequency of 14.89%. The number of VBAC cases was 989, whose rate was 9.88% in prior CS women. The number （proportions） of PPH was 3658 （2.88%） in L1 （PPH volume： ≥900 and 〈1500 mL）, 520 （0.41%） in L2 （PPH volume： ≥1500 and〈2100 mL）, and 201 （0.16%） in L3 （PPH volume： ≥2100 mL）. The Ln （n= 1, 2, 3, etc.） represented the increasing order of PPH severity. In the adjusted results, compared with spontaneous vaginal delivery （SVD） as the reference group, in the adjusted result for nulliparous, there was a decreased PPH risk in CS with indications （OR： 2.32; CI： 2.04-2.62）, which was lower than that of CS without indications （OR： 2.50; CI： 2.01-2.96）. The highest PPH risk in all subgroups （i.e. nulliparous and multiparous groups） was observed in the RC （OR： 3.61; CI： 3.16-4.17）, which was nearly twice higher than that of the VBAC （OR： 1.82; CI： 1.33-2.52）. CAVB （OR： 1.03; CI： 0.65-1.62） showed no significant difference with the reference group. Thus, we deemed that CS should be avoided in nulliparous pregnancies unless indicated, to prevent or reduce the rates for the use of RC or VBAC which are high risks of severe PPH to the parturient women.

Design of Irregular QC-LDPC Code Based Multi-Level Coded Modulation Scheme for High Speed Optical Communication Systems

In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.

Efficient error estimation in quantum key distribution

In a quantum key distribution（QKD） system, the error rate needs to be estimated for determining the joint probability distribution between legitimate parties, and for improving the performance of key reconciliation. We propose an efficient error estimation scheme for QKD, which is called parity comparison method（PCM）. In the proposed method, the parity of a group of sifted keys is practically analysed to estimate the quantum bit error rate instead of using the traditional key sampling. From the simulation results, the proposed method evidently improves the accuracy and decreases revealed information in most realistic application situations.

基于数字信号处理器的IEEE 802.11ac低密度奇偶校验码编码器的设计与实现

本文提出了适用于IEEE 802.11ac标准草案LDPC码编码器的设计方案。设计方案针对LDPC码的校验矩阵的准循环、双对角线的结构特点,采用了具有低复杂度的快速迭代算法,在FreeScale公司的MSC8156 DSP平台上实现了LDPC码的编码器,并对代码进行了合理的优化。测试结果显示,使用MSC8156的一个运算核心进行编码的平均速率可达1Gbps以上,满足系统要求。

Parity space-based fault diagnosis of CCBII braking system

Fault diagnosis is a key issue of the CCBII(computer controlled brake II) braking system, because the CCBII braking system is very complicated and nonlinear, which may exhibit isolated and multi-component coupled faults. A parity space-based method was proposed for fault diagnosis of CCBII braking systems. Firstly, the mathematical models were established according to three function modules of CCBII braking systems where the air fluid theory was utilized. Then, parity vector and threshold function were designed for each output of the system so as to identify more system faults. Fault character matrix was built based on the causal relationship between the output and the fault according to the system function and internal structure. Finally, fault detection and isolation can be realized by the comparison of the observed system output and the fault character matrix. Simulation results show that the proposed method is entirely feasible and effective.

Quantitative Analysis of the Loads Acting on the Abrasive Grits in the Diamond Sawing of Granites

An experimental study was carried out to quantitati ve ly evaluate the loads acting on the diamond grits during circular sawing of two kinds of typical granite with diamond segmented saw blade. Measurements were mad e of the horizontal and vertical force components and the consumed power in order to obtain the tangential and the normal force components. The temperatures at the diamond-granite contact zone were measured using a foil thermocouple. T he measurement, together with the net sawing power, was subsequently used to est imate the energy partition to the granite by a temperature matching technique. B ased on the energy partition values, the temperatures at individual cutting poin ts were estimated using an analytical model. SEM was used to follow the topograp hies of worn diamond segments. The average force acting on each diamond grit was found to be only 4% of the diamond compressive strength measured by a static me thod. The strength disparity of diamond grits and the random protrusion of grits beyond bond matrix should be significant factors in accounting for the wear of diamond grits. The wear of diamond grits was also found to be closely related to the high temperatures generated at individual cutting points and the pop-outs of diamonds from the bond matrix might be mainly attributed to the heat conducte d to the segments.

Construction of protograph LDPC codes with circular generator matrices

The application of protograph low density parity check （LDPC） codes involves the encoding complexity problem. Since the generator matrices are dense, and if the positions of ＂1＂ s are irregularity, the encoder needs to store every ＂1＂ of the generator matrices by using huge chip area. In order to solve this problem, we need to design the protograph LDPC codes with circular generator matrices. A theorem concerning the circulating property of generator matrices of nonsingular protograph LDPC codes is proposed. The circulating property of generator matrix of nonsingular protograph LDPC codes can be obtained from the corresponding quasi-cyclic parity check matrix. This paper gives a scheme of constructing protograph LDPC codes with circulating generator matrices, and it reveals that the fast encoding algorithm of protograph LDPC codes has lower encoding complexity under the condition of the proposed theorem. Simulation results in ad- ditive white Gaussian noise （AWGN） channels show that the bit error rate （BER） performance of the designed codes based on the proposed theorem is much better than that of GB20600 LDPC codes and Tanner LDPC codes.

Parity recognition of blade number and manoeuvre intention classification algorithm of rotor target based on micro-Doppler features using CNN

This paper proposes a parity recognition of blade number and manoeuvre intention classification algorithm of rotor target based on the convolutional neural network(CNN) using micro Doppler features. Firstly, the time-frequency spectrograms are acquired from the radar echo by the short-time Fourier transform.Secondly, based on the obtained spectrograms, a seven-layer CNN architecture is built to recognize the blade-number parity and classify the manoeuvre intention of the rotor target. The constructed architecture contains a leaky rectified linear unit and a dropout layer to accelerate the convergence of the architecture and avoid over-fitting. Finally, the spectrograms of the datasets are divided into three different ratios, i.e., 20%, 33% and 50%,and the cross validation is used to verify the effectiveness of the constructed CNN architecture. Simulation results show that, on the one hand, as the ratio of training data increases, the recognition accuracy of parity and manoeuvre intention is improved at the same signal-to-noise ratio(SNR);on the other hand, the proposed algorithm also has a strong robustness: the accuracy can still reach 90.72% with an SNR of – 6 dB.

针对信息节点振荡特性的改进LDPC译码方法

在中高信噪比情况下,信息节点值在译码迭代中可能出现在0和1之间振荡的情况,从而使最终的误比特率上升。针对这种情况,提出了将出现振荡情况且初始软信息较小的信息节点所携带的初始信息认定为不可靠并忽略掉的改进译码算法,有效的降低了误比特率。对码长为504bit码率为2/3的LDPC非规则规则码进行了仿真实验,在Eb/N0为0.5dB到2.5dB的范围内均能取得优于传统BP译码算法0.3dB的增益。

Unnatural parity resonance states in positron-excited hydrogen scattering

The coupled-channels optical method for positron scattering has been applied to investigate resonance states with unnatural parities in a positron-excited hydrogen system. The positronium formation channels and continuum channel are included via a complex equivalent local potential. Resonance states with angular momenta L =- 1 to L = 2 and parities （-1）L＋1 are calculated. Resonance energies and widths are reported and compared with other theoretical calculations. We found that the opening positronium formation channels play an important role in forming nondipole Feshbach resonances.

一类性能好、复杂度低的纠错编码——乘加码

对一类性能好且复杂度低的纠错编码技术——乘加码进行了介绍。他是在单校验位的Turbo乘积码(Single Parity Check Turbo Product Code)的基础上改进而来的,即由单校验位的Turbo乘积码作为外码,码率为1的递归卷积码作为内码串行级联而成。介绍了乘加码的编码方式和译码方法,并给出了其性能分析。对于一定的分组长度,这类码表现出与Turbo码相近的性能,但其译码复杂度要远远低于Turbo码。

Equivalent low-order angular flux nonlinear finite difference equation of MOC transport calculation

The key issue in accelerating method of characteristics(MOC)transport calculations is in obtaining a completely equivalent low-order neutron transport or diffusion equation.Herein,an equivalent low-order angular flux nonlinear finite difference equation is proposed for MOC transport calculations.This method comprises three essential features:(1)the even parity discrete ordinates method is used to build a low-order angular flux nonlinear finite difference equation,and different boundary condition treatments are proposed;(2)two new defined factors,i.e.,the even parity discontinuity factor and odd parity discontinuity factor,are strictly defined to achieve equivalence between the low-order angular flux nonlinear finite difference method and MOC transport calculation;(3)the energy group and angle are decoupled to construct a symmetric linear system that is much easier to solve.The equivalence of this low-order angular flux nonlinear finite difference equation is analyzed for two-dimensional(2D)pin,2D assembly,and 2D C5G7 benchmark problems.Numerical results demonstrate that a low-order angular flux nonlinear finite difference equation that is completely equivalent to the pin-resolved transport equation is established.