Probing nonlocal correlations in magnetic rare-earth clusters

TL;DR

This paper investigates nonlocal quantum correlations in rare-earth magnetic clusters, demonstrating how conductance measurements relate to entanglement entropy changes, advancing experimental control of quantum entanglement in such systems.

Contribution

It introduces a method linking differential conductance features to entanglement entropy variations in rare-earth spin clusters, enabling experimental probing of quantum correlations.

Findings

Conductance profiles correlate with entanglement entropy changes.

Distinct braiding patterns indicate stepwise entanglement variations.

Results suggest potential for quantum control in lanthanide systems.

Abstract

Understanding and quantifying entanglement entropy is crucial to characterize the quantum behaviors that drive phenomena in a variety of systems. Rare-earth spin complexes, with their unique magnetic properties, provide fertile ground for exploring these nonlocal correlations. In this work, we study Eu$^{2+}$ ions deposited on a Au(111) substrate, modeling finite clusters of large spin-moments using a Heisenberg Hamiltonian parameterized by first-principles calculations. Our analysis reveals a one-to-one correspondence between structures in the differential conductance profiles and changes in the von Neumann entanglement entropy of bipartite subsystems, influenced by probe-ion separation and applied magnetic fields. Distinct braiding patterns in the conductance profiles are shown to correspond to stepwise changes in the entanglement entropy, providing a new avenue for investigating quantum correlations. These results establish a foundation for experimentally probing and controlling entanglement in lanthanide-based systems, with potential applications in quantum technologies.