电-声子耦合强度对量子点系统噪声的影响

利用Lang-Firsov正则变换和Keldysh非平衡格林函数方法研究了低温下具有电子-声子相互作用的量子点系统的噪声。我们特别注意了电-声子耦合强度的变化对量子点系统噪声的影响。数值结果表明：随着电-声子耦合强度的增大,系统的噪声增大,同时微分噪声谱中会出现一系列的声子伴带峰,峰的高度和数目对电-声子耦合强度的变化非常敏感。我们也研究了系统的Fano因子,它显示系统噪声对肖特基(Schottky)公式的偏离。在高偏压区,Fano因子随着电-声子耦合强度的增大而增大。     

单发次皮秒脉冲对比度的三阶自相关法测试技术

为了测试单发次皮秒脉冲对比度,设计并研制了非共轴三阶自相关仪。三阶自相关仪参数优化设计中,在确保获得正确的相关耦合信号的前提下,充分利用KDP晶体的极化张量,寻找有效非线性系数相对较高的相位匹配点,在满足非共线相位匹配条件的同时兼顾群速匹配,为增大时间测试范围,选取较大的入射光夹角。采用分区测试和图形重构技术,增大对比度测试的动态范围,结果显示采用两个科学级CCD测试的脉冲对比度在105左右。     

Photon-assisted and spin-dependent shot noise in magnetic-field tunable ZnSe/Zn_(1-x)Mn_xSe structures

We have investigated the photon-assisted shot noise properties in the magnetic field tunable heterostructures. Transport properties of the model structure are strongly dependent on the oscillatory field and the magnetic field. In this structure,electrons can absorb or emit one or multi-photons to reach the quasi-bound state. As a result, the transmission properties are affected considerably by photon-assisted tunneling and these features cause the nontrivial variations in the shot noise and Fano factor. It is found that the shot noise becomes spin-dependent and can be modulated not only by the magnetic field, but also by the oscillatory field. Both the spin-up and spin-down components of the shot noise can be greatly suppressed by the magnetic field, and can also be drastically enhanced by the harmonically driven field. Furthermore,with increasing external magnetic field, it is important to note that the enhanced intensity is decreased, even suppressed.These results suggest another method to suppress the shot noise via modulating the oscillatory field at a diluted-magneticsemiconductors/semiconductor structure.     

Shot noise in electron transport through a double quantum dot: a master equation approach

We study shot noise in tunneling current through a double quantum dot connected to two electric leads.We derive two master equations in the occupation-state basis and the eigenstate basis to describe the electron dynamics.The approach based on the occupation-state basis,despite being widely used in many previous studies,is valid only when the interdot coupling strength is much smaller than the energy difference between the two dots.In contrast,the calculations using the eigenstate basis are valid for an arbitrary interdot coupling.Using realistic model parameters,we demonstrate that the predicted currents and shot-noise properties from the two approaches are significantly different when the interdot coupling is not small.Furthermore,properties of the shot noise predicted using the eigenstate basis successfully reproduce qualitative features found in a recent experiment.     

Results of a beer game experiment: Should a manager always behave according to the book?

We investigate the effect of the literature suggested optimal values of the parameters of a dynamic decision‐making heuristic in the presence of semirationally managed supply chain echelons using a soft coded one‐to‐one version of The Beer Game as an experimental platform. According to the counterintuitive results obtained in this study, it is possible for a “rational manager” to obtain higher costs than the costs generated by a “semirational manager.” Thus, the results do not support the use of the well‐established decision parameter values for the echelon of concern if the other echelons' inventories are managed suboptimally. © 2015 Wiley Periodicals, Inc. Complexity 21: 190–199, 2016     

The law of the iterated logarithm for the solution of the Burgers equation with random initial data

The law of the iterated logarithm is established for the solution of the one-dimensional Burgers equation in the case where the initial potential is described by a zero-range shot noise.Translated fromMatematicheskie Zametki, Vol. 64, No. 6, pp. 812–823, December, 1998.The author wishes to thank Professor A. V. Bulinskii for setting the problem and for his attention to the work on the paper.     

介观系统普适电导涨落的Fokker-Planck方程研究

利用一维介观系统的随机矩阵本征值分布函数的严格表达式,对闪粒噪声功率谱和无序NS结的普适电导涨落进行了计算,得出的严格结果如下:VarG_f=(1/2)×46/2835和VarG_(NS)=32(1/15-6/π~4).     

宁波金塘锚地走锚断链分析

通过对锚泊船进行受力计算、比较，分析急流、偏荡、浅水效应、锚重等因素与单锚泊船走锚的关系，探寻在金塘锚地及附近经常发生走锚、断链事故的原因，提出了一些防范措施．     

全长粘结式锚杆的非局部摩擦分析

本文对Oden等提出的非局部摩擦模型进行了修正,得到了修正后的非局部摩擦模型.并应用于全长粘结式锚杆问题.文中利用Mindlin问题的位移解导出的全长粘结式锚杆沿杆体表面所受的剪应力的弹性解,对全长粘结式锚杆进行非局部摩擦分析,得到了在修正后的非局部摩擦模型下的全长粘结式锚杆的侧剪应力.文中修正的非局部摩擦模型下的全长粘结式锚杆的剪应力分布规律与试验得到的结果以及局部摩擦模型(库仑模型)下的计算结果进行了对比,结果表明修正的非局部摩擦模型下的计算结果与实验更符合.因此在描述此锚杆剪应力时,非局部摩擦模型比局部摩擦模型(库仑模型)更接近的实际.     

On the role of shot noise in carrier‐envelope phase stabilization

This paper represents a systematic investigation of detection shot noise in carrier‐envelope phase (CEP) stabilization. Numerical simulations are conducted to calculate the influence of shot noise in laser oscillators. These results are compared with experimental results for Ti:sapphire lasers. It is found that shot noise imposes a limitation for obtaining sub‐100 mrad CEP jitters. Careful interferometer design is necessary to push this limit toward 10 mrad. In contrast to oscillator stabilization, shot noise appears to play a much more restrictive role in amplifier stabilization. Using spectral interferometry together with spectral broadening in sapphire, it already appears practically challenging to reach sub‐100 mrad jitters. Adaption of the optical nonlinearity in the broadening step appears key to further improvements of the CEP jitter of amplified systems. We believe that these improvements open a perspective for currently unfeasible applications of CEP stabilized pulses. Moreover, our considerations can be easily adapted to CEP stabilization of other laser types beyond Ti:sapphire.