对《二维六角形晶格伊辛模型的重正化群解》一文的进一步计算

针对《二维六角形晶格伊辛模型的重正化群解》一文中有关〈V〉0的计算进行了修正,给出了新的重正化群的变换、重正化群的线性化变换矩阵以及临界指数.     

二维随机三角点阵上O(3)σ模型β函数的研究

用改进的蒙特卡洛重正化群方法讨论了二维随机三角点阵上O(3)σ模型β函数行为.在弱耦合区的行为与二圈图微扰论的结果一致,g>0.8以后,β函数下降陡度突然增加,反映了高阶微扰项及非微扰项的贡献.     

量子多体系统的线性张量重正化群方法

文章简述了数值重正化群方法的历史发展,包括威耳逊（Wilson）的数值重正化群算法,S.R.White的密度矩阵重正化群方法,以及近期迅速发展的处理强关联量子系统的几种张量网络态与张量网络算法.在此基础上,文章重点介绍了作者最近提出的用于研究量子多体系统热力学性质的线性张量重正化群方法,以及该方法在一维和二维量子系统中的应用.     

QGP有效微扰论中纯规范场的二圈热力学势

使用基于硬热圈(HTL)的重求和方法,计算了QGP中纯规范场的二圈热力学势及其重整化,得到了包含集体效应的结果.     

二维静态时空中Dirac场的重正化能动张量和Casimir效应

在一般渐近平直的二维静态黑洞时空中,利用重正化能动张量的一般性质, 对位于两“平行板”间满足Dirichlet条件的无质量Dirac场的重正化能动张量的真空期待值进行了分析和计算, 得到了一般表达式.利用该表达式可以给出各种具体渐近平直二维静态黑洞时空中的相应Casimir力.对于重正化能动张量及Casimir力与真空态定义(包括Boulware 真空态、Hartle-Hawking真空态和Unrum真空态三种情况)、Hawking辐射和反常迹的关系分别进行了讨论，给出了相应的表达式和计算结果. 关键词： 能动张量 Casimir 效应 黑洞 真空态     

φ4模型的蒙特卡洛重整化群研究

本文采用Callaway的蒙特卡洛重整化群方案作出了二维三角点阵φ⁴模型的重整化群流向图、固定点和临界指数.在区域0.1<λ<10⁹内没有发现固定点,大λ极限的结果与Ising模型一致.     

基于局部约束群稀疏的红外图像超分辨率重建

针对红外图像分辨率低、视觉质量差等问题,提出基于局部约束群稀疏模型的红外图像超分辨率重建方法.考虑到红外图像的纹理自相似性和原子系数的群结构稀疏性,首先建立了基于局部约束的群稀疏表示模型.然后,在假定低分辨率图像空间和高分辨率图像空间具有相似流形的前提下,联合局部约束群稀疏表示模型和K-SVD(K奇异值分解)方法,训练得到高低分辨率图像对应的群结构字典对.最后,通过高分辨字典和对应的红外图像群稀疏表示系数重建得到高分辨率的红外图像.实验结果表明,本文方法具有更好的超分辨率效果,无论是在客观评价指标还是主观视觉效果方面都有明显的提高.     

φ~4模型的蒙特卡洛重整化群研究

本文采用Callaway的蒙特卡洛重整化群方案作出了二维三角点阵φ~4模型的重整化群流向图、固定点和临界指数。在区域0.1<λ<10~9内没有发现固定点,大λ极限的结果与Isiog模型一致。     

畸变对hopping电导的影响：Thue Morse纳米结构模型

发展实空间重正化群方法，研究了一维非周期Thue Morse纳米结构链的hopping电导率.计算表明Thue Morse纳米结构体系的晶粒种类、晶粒尺寸对hopping电导有显著的调制作用，界面结构和晶格畸变对hopping电导也有不同程度的影响.从无序度对hopping电导的影响来看，Thue Morse纳米结构链的无序度介于Fibonacci链和周期链之间. 关键词： Thue Morse纳米结构链 重正化群方法 hopping电导 尺寸效应 界面效应     

采用正方元胞的Ising模型实空间重正化群解

在二维正方形晶格上,将元胞取为4格点正方形,采用3种不同的规则定义块自旋状态,进行了重正化群计算,得出了更为精确的结果;解决了元胞内格点数为偶数的重正化群计算问题.     

Mixing renormalization in Majorana neutrino theories

The renormalization of general theories with inter-family mixing of Dirac and/or Majorana fermions is studied at the one-loop electroweak order. The phenomenological significance of the mixing-matrix renormalization is discussed, within the context of models based on the SU(2)_L⊗U(1)_Y gauge group. The effect of radiative neutrino masses present in these models is naturally taken into account in this formulation. As an example, charged-lepton universality in pion decays is investigated in the heavy-neutrino limit. Non-decoupling heavy-neutrino effects induced by mixing renormalization are found to considerably affect the predictions in these new-physics scenarios.     

One-Loop Calculation in Time-Dependent Non-Equilibrium Thermo Field Dynamics

This paper is a review on the structure of thermo field dynamics (TFD) in which the basic concepts such as the thermal doublets, the quasi-particles and the self-consistent renormalization are presented in detail. A strong emphasis is put on the computational scheme. A detailed structure of this scheme is illustrated by the one-loop calculation in a non-equilibrium time-dependent process. A detailed account of the one-loop calculation has never been reported anywhere. The role of the self-consistent renormalization is explained. The equilibrium TFD is obtained as the long-time limit of non-equilibrium TFD.     

Decay widths of the neutral \mathcal{CP}-even MSSM Higgs bosons in the Feynman-diagrammatic approach

In the Minimal Supersymmetric Standard Model (MSSM) we incorporate the Higgs-boson propagator corrections, evaluated up to two-loop order, into the prediction of and for . The propagator corrections consist of the full one-loop contribution, including the effects of non-vanishing external momentum, and corrections of at the two-loop level. The results are supplemented with the dominant one-loop QED corrections and final state QCD corrections from both gluons and gluinos. The effects of the two-loop propagator corrections and of the one-loop gluino contributions are investigated in detail. Our results are compared with the result obtained within the renormalization group approach. Agreement within 10% is found for most parts of the MSSM parameter space. Received: 9 March 2000 / Published online: 14 April 2000     

Renormalization group functions for the Wess–Zumino model: Up to 200 loops through Hopf algebras

We obtain the contributions to the renormalization group functions of all the diagrams containing the unique one-loop primitive divergence of a simple supersymmetric Wess–Zumino model, up to more than 200 loops. The asymptotic behavior of the coefficients in the expansion of the anomalous dimension is analysed.     

Is anti-de Sitter supersymmetry radiatively broken?

We perform the computation of the effective potential of the Wess-Zumino model in anti-de Sitter space to one-loop order. This enables us to obtain the renormalization coefficients of the theory and to prove that they are independent of the choice of a particular extremum of the potential. In spite of the fact that a linear superfield insertion is needed to renormalize the model, we show with complete generality that supersymmetry is preserved to one-loop order at every one of the four classically supersymmetric extrema of the effective potential.     

On the renormalization of the charm quartet model

Some aspects of the renormalization program for the charm quartet model are discussed, with special emphasis on the role played by the Cabibbo angle. The cancellation of divergences in the W-quarks and Higgs-quarks sector is examined by explicit calculations at the one-loop level, both in the unitary and 't Hooft-Feyman gauges. The main analysis is based on a renormalization scheme which allows for the most general counter-terms generated by the Yukawa couplings. A second approach, equivalent at the S-matrix level, is briefly discussed. As a byproduct of our work we verify that the standard perturbative analysis leads to the same expressions for the coefficients of the divergent parts in the renormalization of the gauge coupling g₀ as a recent current algebra formulation of the radiative corrections.     

Application of Asymptotic Methods to Calculating Electroweak Corrections in Polarized Bhabha Scattering

Physics of Atomic Nuclei - Asymptotic expressions for one-loop electroweak radiative corrections to observables of polarized Bhabha scattering are obtained within the on-shell renormalization...     

Restoration of Lorentz invariance in the lattice O(3) model with improved actions

Symanzik one-loop and block-spin renormalization group improved actions are studied by Monte Carlo simulation. Scaling sets in at small correlation length for the considered actions. The approach to the continuum relativistic energy-momentum dispersion is best for Symanzik one-loop improved action.     

Higher-order effects and the vector boson physical parameters

A detailed analysis of the higher-order effects of the vector boson masses and leptonic decay rates is presented. Previous results obtained by different authors are discussed and compared within a simple renormalization scheme. The experimental precision required for a meaningful test of the theory at the one-loop level is also discussed.