Circuit-quantum electrodynamics with direct magnetic coupling to single-atom spin qubits in isotopically enriched 28Si

TL;DR

This paper explores direct magnetic coupling of single-atom spin qubits in isotopically enriched 28Si to superconducting resonators, enabling faster coupling rates than dephasing and potential for dispersive read-out.

Contribution

It demonstrates the feasibility of directly coupling spin qubits to superconducting resonators using magnetic vacuum fields in silicon, a novel approach in circuit-QED.

Findings

Coupling rates surpass single spin dephasing rates.

Enhanced vacuum magnetic fields achieved with modified resonators.

Potential for dispersive read-out of spin qubits.

Abstract

Recent advances in silicon nanofabrication have allowed the manipulation of spin qubits that are extremely isolated from noise sources, being therefore the semiconductor equivalent of single atoms in vacuum. We investigate the possibility of directly coupling an electron spin qubit to a superconducting resonator magnetic vacuum field. By using resonators modified to increase the vacuum magnetic field at the qubit location, and isotopically purified 28Si substrates, it is possible to achieve coupling rates faster than the single spin dephasing. This opens up new avenues for circuit-quantum electrodynamics with spins, and provides a pathway for dispersive read-out of spin qubits via superconducting resonators.