Contrary to field theoretical calculations in the thermodynamic limit where the volume is assumed to be infinitely large, the heavy-ion collisions always carry the effects of finite size. A sufficiently small system size is expected to affect the thermodynamic quantities and the phase diagram of the strongly interacting matter. To study these effects one can take into account the finite spatial extent of the system within the framework of an effective model too, via the restriction of the momentum integrals using discretization or in a simplified case using a low momentum cutoff. We investigated the effects of the finite volume in a vector meson extended Polyakov quark-meson model and found a remarkable change in the thermodynamics and the phase transition, especially in the location of the critical endpoint.
Trans-series from condensates in the non-linear sigma model
Institute of Theoretical Physics, Jagiellonian University(雅盖隆大学理论物理研究所);Département de Physique Théorique et Section de Mathématiques Université de Genève(日内瓦大学理论物理系与数学系)
Hadronic vacuum polarization contribution to the muon $g-2$ with 2+1 flavor lattice QCD on a larger than (10 fm$)^4$ lattice at the physical point
研究了格点量子色动力学计算强子真空极化对μ子$g-2$贡献的系统不确定性。我们调查三个系统的影响,有限体积(FV)的效果,截止效应,和集成方案的依赖性。我们使用PACS 10组态在相同的截止尺度下评估了两种不同体积的(5.4 fm $)^4$和(10.8 fm $)^4$)在物理π质量下的FV效应。对于截止效应,我们比较了两种类型的晶格矢量运营商,这是本地和保守(点分裂)电流,通过改变截止尺度大于(10 fm $)^4$晶格的物理点。对于积分方案的依赖性,我们比较了在(10.8 fm $)^4$)晶格上的物理点处的坐标-和动量-空间积分方案之间的结果。在连续极限下,我们的结果是由$g-2$给出的,其中第一个误差是统计的,第二个误差是系统的.
Effective Field Theory, Black Holes, and the Cosmological Constant
贝肯斯坦提出了体积L^3中总熵S的界S < pi M_P^2 L^2。这种非广延标度表明,量子场论在很大程度上崩溃了。为了调和这种故障与局部量子场论在描述观察到的粒子唯象学的成功,我们提出了紫外和红外截止点之间的关系,这样一个有效场论应该是一个很好的描述自然。我们讨论的宇宙学常数问题的影响。我们发现传统的有效场论所能达到的精确度是有限的:例如,对于电子,来自约束的红外和紫外截止的最小修正(g-2)大于来自顶夸克的贡献。
Electromagnetic pion mass splitting using a Pauli-Villars-regulated photon propagator
Helmholtz Institut Mainz(亥姆霍兹美因茨研究所);Johannes Gutenberg-Universität Mainz(约翰内斯·古腾堡美因茨大学);GSI Helmholtz Centre for Heavy Ion Research(GSI重离子研究中心);PRISMA + Cluster of Excellence & Institut für Kernphysik, Johannes Gutenberg-Universität Mainz(PRISMA卓越集群与约翰内斯·古腾堡美因茨大学核物理研究所);Theoretical Physics Department, CERN(欧洲核子研究中心理论物理部)