Strong entanglement of spins inside a quantum domain wall

TL;DR

This paper demonstrates that spins within a magnetic domain wall are highly entangled at the quantum level, challenging the classical view and opening new avenues for quantum information applications.

Contribution

It reveals the quantum entanglement of spins inside a magnetic domain wall, a phenomenon previously considered classical, and suggests potential for quantum information science.

Findings

Spins inside a domain wall are highly entangled.

The total magnetization indicates global entanglement.

Results can be extended to skyrmions for quantum processing.

Abstract

Magnetic domain walls (DWs) are widely regarded as classical objects in physics community, even though the concepts of electron spins and spin-spin exchange interaction are quantum mechanical in nature. One intriguing question is whether DWs can survive at the quantum level and acquire the quantum properties such as entanglement. Here we show that spins within a DW are highly entangled in their quantum description. The total magnetization of a magnetic DW is nonzero, which is a manifestation of the global entanglement of the collective spin state. These results significantly deepen our understanding of magnetic DWs and enable the application of DWs in quantum information science. The essential physics can be generalized to skyrmions so that they can also play a role in quantum information processing.