A new realization of the long-range entanglement: fractality replacing the topological order

TL;DR

This paper demonstrates a new type of long-range entanglement in a quantum state on a fractal lattice, challenging the traditional association with topological order and suggesting a novel paradigm in quantum matter.

Contribution

It rigorously proves the coexistence of long-range entanglement and short-range correlations in a state lacking topological order, on a fractal lattice geometry.

Findings

Long-range entanglement exists without topological order.

Fractal lattice geometry enables new quantum code structures.

Potential for new quantum information paradigms.

Abstract

The essence of the famed long-range entanglement as revealed in topologically ordered state is the paradoxical coexistence of short-range correlation and nonlocal information that cannot be removed through constant-depth local quantum circuits. Its realization in different quantum states is a focus research topic in both quantum computation and quantum matter. However, the proved realizations are subject to the paradigm of topological order (including its extensions), i.e. via a quantum code structure with macroscopic code distance. Here, we broaden the knowledge of long-range entangled states by rigorously proving the coexistence in a new concrete state. The state describes qudits on the newly experimentally discovered fractal lattice geometry (1.58D) on which the quantum code structure has been shown not to exist, i.e., there is no topological order. Our result might reveal a new paradigm for the realization of the long-range entanglement in many-body quantum states, and might stimulate new studies connecting quantum information and quantum matter.