Space and space-time topologies in a type-II hyperbolic lattice

TL;DR

This paper introduces a new type-II hyperbolic lattice with both spatial and spatiotemporal topologies, realized via electric circuits, demonstrating dynamic topological state transfer and proposing a hyperbolic space-time crystal with intertwined topologies.

Contribution

It discovers and experimentally realizes a type-II hyperbolic Chern insulator with dual edges, demonstrating dynamic transfer of topological states and proposing a novel hyperbolic space-time crystal paradigm.

Findings

Observation of degenerate chiral edge states at inner and outer edges.

Demonstration of anti-time-parity phase transition enabling dynamic transfer.

Proposal of a hyperbolic space-time crystal with intertwined topologies.

Abstract

Recent breakthroughs in hyperbolic lattices have expanded the study of topological phases of matter from Euclidean to non-Euclidean spaces. However, prior work has mostly focused on spatial topological states at the single outer edge of type-I hyperbolic lattices. The dynamic transfer of hyperbolic topological states across multiple edges, as well as the emergence of spatiotemporal topological phenomena, remains largely unexplored. Here, we establish both spatial and spatiotemporal topologies in a newly discovered type-II hyperbolic lattice possessing outer and inner edges. Using electric circuits, we experimentally realize a type-II hyperbolic Chern insulator and directly observe degenerate chiral edge states of opposite chirality at its outer and inner edges. Furthermore, by coupling these counter-propagating chiral edge states, we demonstrate an anti-time-parity phase transition, enabling dynamic transfer between them in arbitrary proportions. Finally, we propose a novel paradigm for constructing a (2+1)-dimensional hyperbolic space-time crystal, which hosts an intertwined topology of spatial Chern and temporal winding numbers, resulting in a unique space-time topological string state. Our work expands the frontier of hyperbolic topological physics, paving the way for the spatiotemporal dynamic manipulation of hyperbolic topological states.