Long-distance coupling of spin qubits via topological magnons

Hetényi, Bence and Mook, Alexander and Klinovaja, Jelena and Loss, Daniel. (2022) Long-distance coupling of spin qubits via topological magnons. Physical review B: Condensed matter and materials physics, 106 (23). p. 235409.

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Official URL: https://edoc.unibas.ch/92103/

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We consider two distant spin qubits in quantum dots, both coupled to a two-dimensional topological ferromagnet hosting chiral magnon edge states at the boundary. The chiral magnon is used to mediate entanglement between the spin qubits, realizing a fundamental building block of scalable quantum computing architectures: a long-distance two-qubit gate. Previous proposals for long-distance coupling with magnons involved off-resonant coupling, where the detuning of the spin-qubit frequency from the magnonic band edge provides protection against spontaneous relaxation. The topological magnon mode, on the other hand, lies in between two magnonic bands far away from any bulk magnon resonances, facilitating strong and highly tuneable coupling between the two spin qubits. Even though the coupling between the qubit and the chiral magnon is resonant for a wide range of qubit splittings, we find that the magnon-induced qubit relaxation is vastly suppressed if the coupling between the qubit and the ferromagnet is antiferromagnetic. A fast and high-fidelity long-distance coupling protocol is presented capable of achieving spin-qubit entanglement over micrometer distances with 1MHz gate speed and up to 99.9% fidelities. The resulting spin-qubit entanglement may be used as a probe for the long-sought detection of topological edge magnons.
Faculties and Departments:05 Faculty of Science > Departement Physik > Physik > Theoretical Nano/Quantum Physics (Klinovaja)
UniBasel Contributors:Klinovaja, Jelena
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Physical Society
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:01 Feb 2023 09:49
Deposited On:01 Feb 2023 09:49

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