论文标题
4D爱因斯坦 - 马克斯韦斯 - 高斯 - 邦网重力与标量场的黑洞
Black holes in 4D Einstein-Maxwell-Gauss-Bonnet gravity coupled with scalar fields
论文作者
论文摘要
在本文中，通过“ Kaluza-Klein样”过程研究了Einstein-Maxwell-Gauss-Bonnet-axion理论。在有限温度下与背景磁场在三维的有限温度下对系统，可获得四维对照黑洞溶液与较高衍生术语的偶联。添加张量型扰动后，分别在高温和低温下计算剪切粘度与熵密度比。发现固定粘度与未加成黑洞的熵粘度与熵密度比的行为与$ 5 $维的时空相似，当温度降低时违反了Kovtun Starinets-Son的限制。此外，该比率的主要特征几乎保持不变，$ 4 $尺寸，其特征是低温$ t $在低温下的$（t/δ）^2 $，$δ$与来自标量字段的系数$β$成比例。还讨论了因果分析的困难，这主要是由运动方程中消失的动量项引起的。
Einstein-Maxwell-Gauss-Bonnet-axion theory in $4$-dimensional spacetime is investigated in this paper through a "Kaluza-Klein-like" process. Dual to systems at finite temperature with background magnetic field on three dimensions, the four-dimensional dyonic black hole solution coupled with higher derivative terms is obtained. After the tensor-type perturbation is added, the shear viscosity to entropy density ratio is calculated at high temperature and low temperature separately. The behaviour of shear viscosity to entropy density ratio of uncharged black holes is found to be similar with that in $5$-dimensional spacetime, violating the Kovtun-Starinets-Son bound as well when temperature becomes lower. In addition, the main feature of this ratio remains almost unchanged in $4$ dimensions, which is characterised by $(T/Δ)^2$ at low temperature $T$, with $Δ$ proportional to the coefficient $β$ from scalar fields. The difficulty in causal analysis is also discussed, which is mainly caused by the vanishing momentum term in equations of motion.
