Immirzi参数的扰动运行

A Discussion on Possible Effects of the Barbero-Immirzi Parameter at the TeV-scale Particle Physics

In this paper, we analyse a curvature- and torsion-square quantum gravity action with an additional Holst term minimally coupled to a massive Dirac field in four dimensions. The main purpose here is to try to estimate and compare the value of the Barbero-Immirzi (BI) parameter with its currently known results. To do that, we work out the physical mass of the fermion as a function of this parameter in a perturbative one-loop calculation, assuming the scenario of a physics at the TeV-scale.

Holst Action的重整化群流

Renormalization Group Flow of the Holst Action

以自旋联系和维尔本为基本场变量，研究了量子引力的重整化群性质。尺度相关的有效作用量必须在时空同构和局部坐标系旋转下都是不变的。非微扰RG方程求解显式截断的理论空间定义的Holst型行动，其中涉及一个运行的Immirzi参数的三个参数的家庭。我们发现了一个渐近安全的基本理论存在的证据，可能不等价于以同样方式构造的度规量子引力。

Non-Perturbative Quantum Correction to the Reissner-Nordström spacetime with Running Newton's Constant

We study the consequences of the running Newton's constant on several key aspects of spherically symmetric charged black holes by performing a renormalization group improvement of the classical Reissner-Nordström metric within the framework of the Einstein-Hilbert truncation in quantum Einstein gravity. In particular, we determine that the event horizon surfaces are stable except for the extremal case and we corroborate the appearance of a new extremality condition at the Planck scale that hints at the existence of a final stage after the black hole evaporation process. We find explicit expres…

宇宙学原始张量功率谱的Holonomy修正

Holonomy corrections to the cosmological primordial tensor power spectrum

圈量子引力是非微扰引力的主要候选理论之一。在此框架下，导出了FLRW背景下引力子传播方程的完整修正。我们调查的后果，在de-Sitter和慢卷暴胀，为n=-1/2的张量功率谱的这些修正。根据Barbero-Immirzi参数的值，可以预期几个观测特征。

O$(N)$自由能和圆盘电容器的跑动耦合与非微扰修正

Running coupling and non-perturbative corrections for O$(N)$ free energy and for disk capacitor

本文用Wiener-Hopf方法求解O(N)非线性sigma模型的TBA方程，引入跑动耦合消除对数项，发现O(3)情形下重振理论失效，但通过映射到圆盘电容器问题，中值重求和规则给出正确首阶非微扰修正，并与数值解吻合。

Non-perturbative quantum Galileon in the exact renormalization group

We investigate the non-perturbative renormalization group flow of the scalar Galileon model in flat space. We discuss different expansion schemes of the Galileon truncation, including a heat-kernel based derivative expansion, a vertex expansion in momentum space and a curvature expansion in terms of a covariant geometric formulation. We find that the Galileon symmetry prevents a quantum induced renormalization group running of the Galileon couplings. Consequently, the Galileon truncation only features a trivial Gaussian fixed point.

Perturbative running of the twisted Yang-Mills coupling in the gradient flow scheme

We report on our ongoing computation of the perturbative running of the Yang-Mills coupling using gradient flow techniques. In particular, we use the gradient flow method with twisted boundary conditions to perform a perturbative expansion of the expectation value of the Yang-Mills energy density up to fourth order in the coupling at finite flow time. We regularise the resulting integrals using dimensional regularisation, and reproduce the universal coefficient of the 1/ε term in the relation between bare and renormalised couplings. The computation of the finite part leading to a determination…

The twisted gradient flow running coupling in SU(3): a non-perturbative determination

We report some preliminary results of our ongoing non-perturbative computation of the twisted 't Hooft running coupling in a particular set-up, using the gradient flow to define the coupling and step scaling techniques to compute it. For the computation we considered a pure gauge SU(3) theory in four dimensions, defined on the lattice on an asymmetrical torus endowed with twisted boundary conditions in a single plane, and related the energy scale of the coupling to an effective size combining the size of the torus and the rank of the gauge group. Additionally, we explore some of the effects of…

非微扰QCD - I中的运动耦合裸顶点与y-max逼近

Running Coupling in Non-Perturbative QCD - I. Bare Vertices and y-max Approximation

最近声称，在量子色动力学的胶子传播子消失在红外极限，而鬼传播子是比一个简单的极点更奇异，分析和数值研究。即使在戴森-施温格方程中的顶点被认为是裸露的水平上，这幅图也得到了支持。运行耦合被证明是唯一确定的方程，并有一个大的有限红外限制。

Perturbative running of the topological angles

We argue that in general renormalizable field theories the topological angles may develop an additive beta function starting no earlier than 2-loop order. The leading expression is uniquely determined by a single model-independent coefficient. The associated divergent diagrams are identified and a few independent methods for extracting the beta function in dimensional regularization are discussed. We show that the peculiar nature of the topological angles implies non-trivial constraints on the anomalous dimension of the CP-violating operators and discuss how a non-vanishing beta function affec…

暴胀谱指数的大N运行

The large-N running of the spectral index of inflation

我们扩展了以前的分类的通货膨胀模型的行为在大N，其中N是e-折叠的数量。除了微扰1/N的情况下，其慢滚参数下降的权力1/N，我们介绍了常数，非微扰和对数类。这涵盖了绝大多数的通货膨胀模型。此外，我们计算了所有这些类的频谱倾斜的运行。值得注意的是，我们发现倾斜的运行基本上集群周围的permil水平。我们评论的影响，为未来的实验。

牛顿G的重整化群运行：静态各向同性情形

Renormalization Group Running of Newton's G: The Static Isotropic Case

计算了非微扰量子引力效应对广义相对论经典静态各向同性解的修正。有效引力耦合随距离的缓慢上升被证明涉及一个真正的非微扰尺度，与引力真空凝聚密切相关，因此，它被认为与观测到的有效宇宙学常数有关。提出的量子引力的真空凝聚图像之间的几个类比，在强耦合非阿贝尔规范理论的真空凝聚的非微扰方面的发展。与唯象方法相反，该理论的基本泛函积分公式严重限制了耦合的重整化群演化的可能情形。将牛顿常数$G$的预期运行与已知的QED和QCD中的真空极化诱导效应进行了比较。一般的分析，然后扩展到一组协变的非局部有效场方程，旨在将满量程依赖的$G$，并检查的情况下，静态各向同性度量。有效场方程真空解的存在性一般严格限制标度指数$ν$的可能值。

Notes on interplay of the QCD and EW perturbative corrections to the pole-running top-quark mass ratio

A specific representation of the known one-loop EW correction to the relation between the pole and running $\msbar$-scheme masses of the top-quark through particle masses of the Standard Model is given within the Fleischer-Jegerlehner tadpole scheme, where the vacuum expectation value of the Higgs field is renormalized. The importance of taking into account both the EW and QCD effects in this relation in the considered case is emphasized. It is noted that the discard of the EW corrections leads to over $10\;{\rm{GeV}}$ shift in the difference between the pole and running $t$-quark masses. This…

Non-Perturbative Large N Trans-series for the Gross-Witten-Wadia Beta Function

We describe the non-perturbative trans-series, at both weak- and strong-coupling, of the large N approximation to the beta function of the Gross-Witten-Wadia unitary matrix model. This system models a running coupling, and the structure of the trans-series changes as one crosses the large N phase transition. The perturbative beta function acquires a non-perturbative trans-series completion at large but finite $N$ in the 't Hooft limit, as does the running coupling.

SU（N）纯规范理论中耦合的运行

The running of the coupling in SU(N) pure gauge theories

在SU（4）规范理论中，利用薛定谔泛函技术研究了耦合的运行。当能量达到弦张力$σ$的平方根量级时，运行符合双圈微扰公式。将微扰与运行的非微扰状态相关联并转换为$\msbar$方案允许提取比率$Λ_{\msbar}/\sqrtσ$。然后将结果与文献中SU（2）和SU（3）的类似计算结合使用，以在大的$N$极限中提取$Λ_{\msbar}/\sqrtσ$。我们对$N=3,4$的结果与最近用Parisi平均场方案作为中间方案进行的相同数量的研究一致，而SU（2）中的$Λ_{\msbar}/\sqrtσ$结果相差2.5%。这种差异的可能解释进行了讨论。

重正马龙消去与微扰QCD势的库仑+线性势

Renormalon Cancellation and Perturbative QCD Potential as a Coulomb+Linear Potential

最近的研究表明，微扰QCD势与唯象势和格点计算的QCD势符合得很好。本文综述了微扰QCD势的研究现状和理论背景。我们还报告了我们最近的分析，分析表明，在重正马龙优势图片的基础上，微扰QCD势迅速“收敛”到库仑加线性形式。当我们包含更多的微扰级数项时，可以系统地计算库仑加线性势;直到三个循环运行（我们目前最好的知识），它显示出向晶格结果的收敛。例如，在单回路运行时，线性电势为sigma*r，其中sigma =（2*pi*C_F/beta 0）Lambda_MSbar ^2。

Perturbative Yang-Mills Ground State in the Temporal Gauge

Second order corrections to the perturbative ground state wave functional and vacuum energy of a Yang-Mills theory are calculated in the temporal gauge. Using dimensional regularization, the concepts of renormalization and a running coupling constant are motivated in a spatially gauge invariant way, before the introduction of a scalar product. After definition of a scalar product, it is shown that the renormalization constants of this approach are just those of the Axial gauge.

Cosmic inflation as a renormalization-group flow: the running of power spectra in quantum gravity

We study the running of power spectra in inflationary cosmology as a renormalization-group flow from the de Sitter fixed point. The beta function is provided by the equations of the background metric. The spectra of the scalar and tensor fluctuations obey RG evolution equations with vanishing anomalous dimensions in the superhorizon limit. By organizing the perturbative expansion in terms of leading and subleading logs, we calculate the spectral indices, their runnings, the runnings of the runnings, etc., to the next-to-leading log order in quantum gravity with fakeons (i.e., the theory $R+R^{…

The Odderon in QCD with running coupling

Starting from the leading Odderon solution of the three gluon system in perturbative QCD we introduce, as a first step towards the transition to the nonperturbative region, an infrared cutoff and use the running QCD coupling constant. In our numerical analysis we find that the fixed cut solution with intercept one persists, hinting at a physical Odderon with intercept one and a small t-slope.

N=1/2超对称U（N）规范理论非（反）对易性参数的单圈微扰修正

One-Loop Perturbative Corrections to non(anti)commutativity Parameter of N=1/2 Supersymmetric U(N) Gauge Theory

研究了单圈阶N=1/2超对称U（N）规范理论的微扰修正.结果表明，虽然量子修正的N=1扇区的理论不受影响的C-变形，非（反）交换性参数C收到单圈微扰修正。这些微扰修正是通过对理论的三点和四点函数进行显式单循环计算来计算的。利用适当的Callan-Symanzik方程研究了非（反）交换性参数C的运行。

On the flavour dependence of the $\mathcal{O}(α_s^4)$ correction to the relation between running and pole heavy quark masses

Recently the four-loop perturbative QCD contributions to the relations between pole and running masses of charm, bottom and top quarks were evaluated in the $\rm{\overline{MS}}$-scheme with identical numerical error bars. In this work the flavour dependence of the $\mathcal{O}(α_s^4)$ correction to these asymptotic series is obtained in the semi-analytical form with the help of the least squares method. The numerical structure of the corresponding asymptotic perturbative relations between pole and running $c$, $b$ and $t$-quark masses is considered and the theoretical errors of the $\mathcal{O…

Calculation of the non-perturbative strong coupling from first principles

The success of the screened massive expansion is investigated in the framework of a screened momentum-subtraction scheme for the running of the strong coupling in pure Yang-Mills theory. By the exact Slavnov-Taylor and Nielsen identities, a very predictive and self-contained set of stationary conditions are derived for the optimization of the fixed-coupling expansion, yielding explicit analytical one-loop expressions for the propagators, the coupling and the beta function, from first principles. An excellent agreement is found with the lattice data. In the proposed screened renormalization sch…

Perturbative QCD in acceptable schemes with holomorphic coupling

Perturbative QCD in mass independent schemes leads in general to running coupling $a(Q^2)$ which is nonanalytic (nonholomorphic) in the regime of low spacelike momenta $|Q^2| \lesssim 1 \ {\rm GeV}^2$. Such (Landau) singularities are inconvenient in the following sense: evaluations of spacelike physical quantities ${\cal D}(Q^2)$ with such a running coupling $a(κQ^2)$ ($κ\sim 1$) give us expressions with the same kind of singularities, while the general principles of local quantum field theory require that the mentioned physical quantities have no such singularities. In a previous work, certai…

在QCD中设置重整化标度：最大共形性原理

Setting the Renormalization Scale in QCD: The Principle of Maximum Conformality

精确微扰QCD预言的一个关键问题是确定运行耦合$α_s(μ^2).$的重正化标度$μ$的不确定性。运行耦合在任何规范理论中的目的是求和所有涉及$β$函数的项;事实上，当重正化标度设置正确时，所有由重正化引起的微扰展开中的非共形$β\ne 0$项都被求和到运行耦合中。微扰级数中的其余项则与共形理论中的项相同;即，与$β=0$的对应理论。使用“最大共形性原理”（PMC）得到的尺度固定预测与重整化方案的选择无关--这是重整化群不变性的关键要求。结果避免了重正马龙的重正化，并与阿贝尔极限下的QED标度设置相一致。PMC也是BLM过程、可观测量之间的公度标度关系和格点规范理论中使用的标度设定方法的理论基础。QCD $β$函数中的活性风味$n_f$的数量也被正确地确定。本文讨论了几种确定QCD过程PMC标度的方法。我们表明，一个单一的全球PMC规模，有效的领导阶，可以从微扰QCD截面的基本性质。使用PMC消除重整化标度模糊性和方案依赖性不仅将提高QCD测试的精度，而且还将提高对撞机实验对标准模型之外的新物理的敏感性。