Two-qubit logic between distant spins in silicon

TL;DR

This paper demonstrates a method for entangling two distant semiconductor spin qubits using a superconducting resonator, enabling scalable quantum networks with interactions over much larger distances than traditional methods.

Contribution

The work introduces a resonator-mediated coupling between distant spin qubits in silicon, achieving coherent interactions over 250 micrometers, which is significantly larger than direct coupling distances.

Findings

Observed anti-phase oscillations of spin populations.

Achieved controllable coupling frequency.

Demonstrated potential for scalable quantum networks.

Abstract

Direct interactions between quantum particles naturally fall off with distance. For future-proof qubit architectures, however, it is important to avail of interaction mechanisms on different length scales. In this work, we utilize a superconducting resonator to facilitate a coherent interaction between two semiconductor spin qubits 250 $\mu$m apart. This separation is several orders of magnitude larger than for the commonly employed direct interaction mechanisms in this platform. We operate the system in a regime where the resonator mediates a spin-spin coupling through virtual photons. We report anti-phase oscillations of the populations of the two spins with controllable frequency. The observations are consistent with iSWAP oscillations and ten nanosecond entangling operations. These results hold promise for scalable networks of spin qubit modules on a chip.