  In this paper we propose a space-time random tensor network approach for
understanding holographic duality. Using tensor networks with random link
projections, we define boundary theories with interesting holographic
properties, such as the Renyi entropies satisfying the covariant
Hubeny-Rangamani-Takayanagi formula, and operator correspondence with local
reconstruction properties. We also investigate the unitarity of boundary theory
in spacetime geometries with Lorenzian signature. Compared with the spatial
random tensor networks, the space-time generalization does not require a
particular time slicing, and provides a more covariant family of microscopic
models that may help us to understand holographic duality.
