论文标题
流体性质限制了Horndeski重力
Fluid nature constrains Horndeski gravity
论文作者
论文摘要
在一种新方法中阐明了Horndeski重力的难以捉摸的物理性质，该方法将这类理论描述为耗散性的有效液体。要求后者的本构方程是牛顿流体的方程，这将理论限制为“可行” Horndeski重力的两个断开子类。因此，Horndeski有效流体的应力能量张量，在流体4速度的第一个衍生物中线性，是一个足够的条件，足以使引力波以轻速的速度传播。所有其他Horndeski理论对应于异国情调的非牛顿有效液体。
The elusive physical nature of Horndeski gravity is elucidated in a new approach depicting this class of theories as a dissipative effective fluid. Requiring the constitutive equations of the latter to be those of a Newtonian fluid restricts the theory to only two disconnected subclasses of "viable" Horndeski gravity. Therefore, a stress-energy tensor of Horndeski effective fluid, linear in the first derivatives of the fluid's 4-velocity, is a sufficient condition for gravitational waves to propagate at light speed. All other Horndeski theories correspond to exotic non-Newtonian effective fluids.
