Hyperbolic matter in electrical circuits with tunable complex phases


We introduce and experimentally realize hyperbolic matter as a novel paradigm for topological states, made of particles moving in the hyperbolic plane with negative curvature. Curvature of space is emulated through a hyperbolic lattice using topolectrical circuit networks relying on a newly developed complex-phase circuit element. This original method creates an effectively infinite hyperbolic space without the typical extensive holographic boundary — our system consists of pure bulk matter instead. The experiment is based on hyperbolic band theory, which implies that momentum space of two-dimensional hyperbolic matter is four–, six– or higher–dimensional, as we confirm here in an unprecedented numerical survey of hyperbolic lattices with both open and periodic boundary conditions. We experimentally realize hyperbolic graphene as an example of topologically nontrivial hyperbolic matter. Our work sets the stage to realize interacting hyperbolic matter to challenge our established theories of physics in curved space, while the tunable complex-phase element developed here can be a key ingredient for future experimental simulation of various Hamiltonians with topological ground states.

Nat. Commun. 14, 622 (2023)