The imaginary part of the heavy quark-antiquark potential experienced by moving heavy quarkonia in strongly coupled plasmas dual to theories of gravity is computed by considering thermal worldsheet fluctuations of the holographic Nambu-Goto string. General results for a wide class of gravity duals are presented and an explicit formula for $\mathrm{Im} \, V_{Q\bar{Q}}$ is found in the case where the axis of the moving $\bar{Q}Q$ pair has an arbitrary orientation with respect to its velocity in the plasma. These results are applied to the study of heavy quarkonia propagating through a strongly coupled $\mathcal{N} = 4$ SYM plasma. Our results indicate that the onset of $\mathrm{Im} \, V_{Q\bar{Q}}$ decreases with increasing rapidity (though our analysis is limited to slowly moving quarkonia) and that, in general, a $Q\bar{Q}$ pair is more strongly bound if its axis is aligned with its direction of motion through the strongly coupled plasma.
Shadow of Kottler black hole in the presence of plasma for a co-moving observer
考虑了具有正宇宙学常数$Λ$的（3+1）维球对称黑洞度规.我们使用\cite{1}中提出的一般方法来变换同向移动坐标中的度量。然后，对于一个一般的度量，我们已经评估了角阴影的大小在没有和存在的等离子体。通过使用像差关系，我们然后找到相应的阴影半径，作为一个共同运动的观察者所看到的史瓦西德西特或科特勒时空。详细观测了宇宙学常数$Λ$和等离子体参数$k$对黑洞阴影角尺寸的影响。最后，利用观测到的M87 $^*$和Sgr A $^*$黑洞的角尺寸，用宇宙学常数$Λ$（或哈勃常数$H_0$）的观测值来约束等离子体参数$k$的值.
