Hyperbolic fracton model, subsystem symmetry, and holography

The fracton states of matter have been argued to mimic gravity. Here, the authors study a simple fracton toy model in anti-de Sitter space and show that it satisfies several important properties of holography. These properties include the correct boundary-bulk subregion duality: that the boundary mutual information (as the classical analog of entanglement entropy) obeys the well-known Ryu-Takayanagi formula, and that a naive black hole has the correct entropy. This work implies a deeper connection between fracton phases and gravity.