Magnetic Skyrmions for Quantum Computing

In this talk, I will introduce a new class of quantum logic elements based on nanoscale topological solitons called skyrmions [1]. In a skyrmion qubit, information is stored in the quantum degree of helicity, and the logical states can be adjusted by electric and magnetic fields, offering a rich operation regime. I will discuss the appropriate fields required to generate single-qubit gates for quantum computing, and skyrmion multiqubit schemes for a scalable architecture with tailored couplings. Scalability, controllability by microwave fields, operation time scales, and readout by nonvolatile techniques converge to make the skyrmion qubit highly attractive as a logical element of a quantum processor.

The applicability to quantum operations, however, depends on the viability of macroscopic quantum tunneling, a precondition for a quantum computer. I will discuss how by tuning the external fields, magnetic skyrmions in frustrated magnets offer a platform for the observation of diverse quantum tunneling effects [2], We predict quantum tunneling processes for a typical skyrmion spin texture of a 5 nm radius to occur with an inverse escape rate within seconds below 100 mK. In the absence of an energy bias, quantum tunneling effects give rise to an energy tunnel splitting in the MHz regime. Our studies suggest that quantum mechanics manifests itself at the macroscopic level of skyrmion helicity. We offer the parameter space for a practical recipe in device architectures to explore magnetic helicity in the solid-state for qubit operations.

[1] C. Psaroudaki and C. Panagopoulos, Phys. Rev. Lett. 127, 067201 (2021).

[2] C. Psaroudaki and C. Panagopoulos, Phys. Rev. B 106, 104422 (2022).