Holographic Complexity Growth Rate in a dual FLRW Universe.

In this paper, taking the large $R$ limit and using the complexity-volume duality, we investigate the holographic complexity growth rate of a field state defined on the universe located at an asymptotical AdS boundary in Gauss-Bonnet gravity and massive gravity, respectively. For the Gauss-Bonnet gravity case, its growth behavior of the state mainly presents three kinds of contributions: one, as a finite term viewed as an interaction term, comes from a conserved charge, the second one is from the spatial volume of the universe and the third one relates the curvature of the horizon in the AdS Gauss-Bonnet black hole, where the Gauss-Bonnet effect plays a vital role on such growth rate. For massive gravity case, except the first divergent term still obeying the growth rate of the spatial volume of the Universe, its results reveal the more interesting novel phenomenons: beside the conserved charge $E$, the graviton mass term also provides its effect to the finite term; and the third divergent term is determined by the spatial curvature of its horizon $k$ and graviton mass effect; furthermore, the graviton mass effect can be completely responsible for the second divergent term as a new additional term saturating an area law.