论文标题
翻译损坏的全息系统中运输的通用界限
Universal Bounds on Transport in Holographic Systems with Broken Translations
论文作者
论文摘要
我们研究了均质全息模型中具有破碎翻译的均质全息模型中的普遍界限的存在。我们以数值验证，在具有动量耗散的全息系统中，可能会违反对熵结合的粘度，但剪切扩散常数仍然受到下面的界限。这证实了这样一个想法，即$η/s $失去了其在非权利主义系统中的特权角色，并且为了找到更多的通用界限，人们应该宁愿看扩散常数。我们通过表明在自发折断的翻译存在下，加强了这一想法，金石扩散常数在普朗克放松时间和蝴蝶速度方面满足了普遍的下限。此外，模型中的所有扩散过程都满足了因因果关系而施加的上限，该界限是根据热度时间给出的，这是光谱中第一个非溶血模式的假想部分以及纵向声音的速度。最后，我们讨论了在全息形成固体中声音速度的结合的存在，我们表明保形值是纵向声子速度的下部（而非上）。尽管如此，我们表明刚度$ \ partial p/\partialε$仍然受上面的共形值所界的。这表明，必须考虑与系统刚度有关的界限，这与其状态方程相关，而不是在声音的传播速度上。
We study the presence of universal bounds on transport in homogeneous holographic models with broken translations. We verify numerically that, in holographic systems with momentum dissipation, the viscosity to entropy bound might be violated but the shear diffusion constant remains bounded by below. This confirms the idea that $η/s$ loses its privileged role in non-relativistic systems and that, in order to find more universal bounds, one should rather look at diffusion constants. We strengthen this idea by showing that, in presence of spontaneously broken translations, the Goldstone diffusion constant satisfies a universal lower bound in terms of the Planckian relaxation time and the butterfly velocity. Additionally, all the diffusive processes in the model satisfy an upper bound, imposed by causality, which is given in terms of the thermalization time -- the imaginary part of the first non-hydrodynamic mode in the spectrum -- and the speed of longitudinal sound. Finally, we discuss the existence of a bound on the speed of sound in holographic conformal solids and we show that the conformal value acts as a lower (and not upper) bound on the speed of longitudinal phonons. Nevertheless, we show that the stiffness $\partial p/\partial ε$ is still bounded by above by its conformal value. This suggests that the bounds conjectured in the past have to be considered on the stiffness of the system, related to its equation of state, and not on the propagation speed of sound.
