Two complex problems on the lattice: transport coefficients and finite chemical potential

After a few remarks about the problem of extracting transport coefficients from lattice QCD calculations, I report on recent developments in applying stochastic quantization and complex Langevin dynamics to field theories with a complex action due to a nonzero chemical potential. First results demonstrate that the sign problem poses no obstacle for this approach, even in the thermodynamic limit. I conclude with a comparison of two simple one-link models, describing a euclidean system at finite chemical potential and a Minkowski system in real time.     

Lattice results on QCD at high temperature and non-zero baryon number density

Studies of QCD thermodynamics on the lattice now can be performed with an almost realistic quark mass spectrum and on quite large lattices. This will soon allow a controlled extrapolation to the continuum limit. We present recent results on the QCD equation of state, discuss deconfining and chiral symmetry restoring aspects of the QCD transition at vanishing chemical potential and show results on baryon number, electric charge and strangeness fluctuations. We briefly discuss the generic structure of Taylor expansion coefficients in the vicinity of the chiral phase transition and comment on the determination of the anticipated chiral critical point within the framework of Taylor expansions of the QCD partition function.     

Gravity and Spin Forces in Gravitational Quantum Field Theory

In the new framework of gravitational quantum field theory (GQFT) with spin and scaling gauge invariance developed in Phys. Rev. D 93 (2016) 024012-1, we make a perturbative expansion for the full action in a background field which accounts for the early inflationary universe. We decompose the bicovariant vector fields of gravifield and spin gauge field with Lorentz and spin symmetries SO(1,3) and SP(1,3) in biframe spacetime into SO(3) representations for deriving the propagators of the basic quantum fields and extract their interaction terms. The leading order Feynman rules are presented. A tree-level 2 to 2 scattering amplitude of the Dirac fermions, through a gravifield and a spin gauge field, is calculated and compared to the Born approximation of the potential. It is shown that the Newton's gravitational law in the early universe is modified due to the background field. The spin dependence of the gravitational potential is demonstrated.     

The gauge transformation of the modified KP hierarchy

In this paper, we firstly investigate the successive applications of three elementary gauge transformation operators T_i with i = 1,2,3 for the mKP hierarchy in Kupershmidt-Kiso version, and find that the gauge transformation operators T_i can not commute with each other. Then two types of gauge transformation operators T_D and T_I constructed from T_i are proved that they can commute with each other. In particular, T_I is introduced for the first time in the literature. And the successive applications of T_D and T_I in the form of T^(n,k), which is the product of n terms of T_D and k terms of T_I, are derived in three cases for different n and k. At last, the corresponding successive applications of T_D and T_I on the eigenfunction Φ, the adjoint eigenfunction Ψ and the tau functions τ₀ and τ₁ are considered.     

On the -compact groups corresponding to the -adic reflection groups

There exists an infinite family of -compact groups whose Weyl groups correspond to the finite -adic pseudoreflection groups of family 2a in the Clark-Ewing list. In this paper we study these -compact groups. In particular, we construct an analog of the classical Whitney sum map, a family of monomorphisms and a spherical fibration which produces an analog of the classical -homomorphism. Finally, we also describe a faithful complexification homomorphism from these -compact groups to the -completion of unitary compact Lie groups.

     

中厚板轧制过程中平面形状控制实验研究

为减少轧制中钢板的切边、切头尾量,提高钢板的成材率,利用厚板展宽轧制法(MAS)对轧制过程中钢板的平面形状控制进行了试验研究.在简述平面形状控制原理的基础上,建立了平面形状控制的试验模型,并通过合理设定轧制速度,达到提高轧制钢板矩形化的目的.试验数据表明,MAS轧制法可以减少钢板的切损量,明显地提高生产效益.     

基于PSO的板形板厚小波神经网络解耦PID控制

针对板形控制和板厚控制是相互耦合的综合系统,提出了一种新的解耦PID控制算法·首先用小波神经网络构造α阶时延逆系统,对综合系统进行输入输出解耦;然后对解耦后的独立的单变量系统采用PID控制·这种解耦方法无论是从理论分析还是仿真验证,均证明是可以实现完全解耦的·考虑到被控对象是一个带有时滞的非线性系统,提出采用PSO优化算法对PID参数进行自适应调整·仿真结果表明所用方法简单有效,并具有良好的跟随性能和抗干扰能力;其控制效果优于传统的解耦PID控制·     

光纤菲佐应变传感器的波分频分复用方法

将波分复用技术与空间频率复用技术相结合,提出了新的光纤菲佐应变传感器波分频分复用方法:在粗波分复用(CWDM)的不同波段实现具有不同腔长的光纤菲佐应变传感器的空间频率复用。描述了基于该方法的光纤菲佐应变传感器复用系统的结构、原理及实验结果,讨论了复用技术中可能产生的串扰的影响及其解决方法。实验结果表明,该方法大大提高了光纤菲佐应变传感器的复用能力,可复用40个以上的菲佐应变传感器,且其应变测量精度达±5με,可满足实际应用的要求。     

单板条层积材力学模型的验证与分析

在利用弹性力学能量原理建立的单板条层积材力学模型基础上,应用层合板理论计算单板条层积材的宏观弹性常数。通过在单板条上黏贴应变片的方法测定杨木单板条的各项弹性常数,并得出了单板条弹性常数与单板条对应密度的关系方程。在此基础上,通过压制不同铺装角度和不同组坯结构的单板条层积材来对计算结果进行验证,验证结果表明,以能量原理为基础,采用层合板理论来预测单板条层积材的力学模型精度较高。     

The intrinsical character of the electronic correlation in an electron gas

By introducing the phase transformation of electron operators, we map the equation of motion of an one-particle Green's function into that of a non-interacting one-particle Green's function where the electrons are moving in a time-depending scalar potential and pure gauge fields for a D-dimensional electron gas, and we demonstrate that the electronic correlation strength strongly depends upon the excitation energy spectrum and collective excitation modes of electrons. It naturally explains that the electronic correlation strength is strong in the one dimension, while it is weak in the three dimensions.