标题： 各向异性磁场存在下的全息朗之万扩散特性 显示英文标题

标题： Aspects of holographic Langevin diffusion in the presence of anisotropic magnetic field

摘要： 我们重新研究了重夸克在存在磁场的强耦合各向异性等离子体中运动时的全息Langevin扩散系数$\mathcal{B}$。 在磁性膜模型中，通过膜范式计算了Langevin扩散系数，该模型已被广泛研究，以通过全息方法探讨磁场对强耦合QCD场景中各种可观测量的影响。 除了确认一些传统结论外，我们还在磁各向异性等离子体中的五个Langevin扩散系数中发现了几个新的有趣特性。 观察到横向Langevin扩散系数更依赖于运动方向，而不是动量扩散的方向，在超高速极限下，而当运动速度足够低时，会得到相反的结论。 对于纵向 Langevin 扩散系数，我们发现运动垂直于$\mathcal{B}$会以任何固定速度更强地影响 Langevin 系数。 我们还应强调，所有五个 Langevin 系数都会随着速度的增加而变大。 我们发现各向同性背景中的普遍关系$\kappa^{\parallel}>\kappa^{\perp}$在一种新的不同情况下被破坏，即夸克平行于$\mathcal{B}$运动。 这是另一个特别的例子，说明在各向异性背景下普遍关系会发生破坏。 此外，我们发现破坏的临界速度会随着$\mathcal{B}$的增加而变大。 显示英文摘要

摘要： We revisit the holographic Langevin diffusion coefficients of a heavy quark, when travelling through a strongly coupled anisotropic plasma in the presence of magnetic field $\mathcal{B}$. The Langevin diffusion coefficients are calculated within the membrane paradigm in the magnetic branes model which has been extensively studied to investigate the magnetic effects on various observables in strongly coupled QCD scenarios by holography. In addition to confirming some conventional conclusions, we also find several new interesting features among the five Langevin diffusion coefficients in the magnetic anisotropic plasma. It is observed that the transverse Langevin diffusion coefficients depend more on the direction of motion rather than the directions of momentum diffusion at the ultra-fast limit, while one would find an opposite conclusion when the moving speed is sufficiently low. For the Longitudinal Langevin diffusion coefficient, we find that motion perpendicular to $\mathcal{B}$ affects the Langevin coefficients stronger at any fixed velocity. We should also emphasize that all five Langevin coefficients are becoming larger with increasing velocity. We find that the universal relation $\kappa^{\parallel}>\kappa^{\perp}$ in the isotropic background, is broken in a different new case that a quark moving paralleled to $\mathcal{B}$. This is one more particular example where the violation of the universal relation occurs for the anisotropic background. Further, we find the critical velocity of the violation will become larger with increasing $\mathcal{B}$.