Topological Spin Textures Enabling Quantum Transmission

Abstract

Quantum spintronics is an emerging field focused on developing novel applications by utilizing the quantum coherence of magnetic systems. A key challenge in this context is achieving scalable long-range quantum information transmission in magnetic systems. Here, we propose a novel transmission scheme based on topological spin textures in a hybrid architecture combining a magnetic racetrack and localized spin qubits. We demonstrate this principle by employing the domain wall (DW), the most fundamental texture, to transport quantum signal between distant qubits. We introduce a measurement-free protocol that utilizes DW mobility to enable high-fidelity and tunable entanglement generation. Furthermore, we demonstrate that spin qubits can function as quantum stations on the racetrack, enabling flexible state transfer among fast-moving DWs on a single track. Finally, we discuss concrete material platforms to implement the proposed scheme. Our work introduces a new hybrid quantum platform that merges topological spin textures with solid-state qubits, offering a scalable architecture for quantum information processing and opening promising directions for quantum spintronics.

Figures (3)

• Figure 1: (a) Schematic diagram illustrating topological quantum signal transmission in a hybrid system, where spin qubits interact with a magnetic nanowire hosting mobile DW textures. (b) A spin qubit interacts with a DW in the magnetic racetrack. The coupling $g(\mathcal{X})$ varies as a function of the distance $\mathcal{X}$ between the qubit and the DW.
• Figure 2: (a) Quantum circuit representation of the remote entanglement protocol, which is robust to the single-qubit rotation $U$. (b) Optimal final DW velocity $v_f$ as a function of the qubit frequency and the racetrack-qubit coupling. (c) Different velocity profiles on the racetrack. (d) Total operational time of the complete protocol as a function of the coupling and separation between spin qubits.
• Figure 3: (a) Two-qubit gate infidelity analysis. The (dashed) red curves illustrate the error caused by spin axis tilting for different spin qubit frequencies $\omega_s$. The purple curve depicts the error induced by qubit frequency shifts. (b) Infidelity due to DW decoherence as a function of the velocity variation and qubit separation.