Thread/State correspondence: the qubit threads model of holographic gravity

We construct a new toy model of the holographic principle, named as holographic qubit threads model, which is an enlightening step towards the issue of spacetime emergence ("it from qubit"). More specifically, we propose for the first time that each bit thread in a locking bit thread configuration is in a "qubit" state, i.e., the quantum superposition state of two orthogonal states. Using this thread/state correspondence, we can construct the explicit expressions for the SS states corresponding to a set of bulk extremal surfaces in the surface/state correspondence, and nicely characterize their entanglement structure. Then we use the locking bit thread configurations to construct the holographic qubit threads model, and we show that it is closely related to the holographic tensor networks, kinematic space, and the connectivity of spacetime.