Resonant Microwave Mediated Interactions Between Distant Electron Spins*

The ability to transfer quantum states and generate entanglement over distances much larger than qubit length scales is an important step towards maximal parallelism and the implementation of two-qubit gates on arbitrary pairs of qubits. Extending qubit interactions beyond the nearest neighbor is particularly beneficial for spin-based quantum computing architectures, which are limited by short-range exchange interactions. Experimental progress towards achieving long-range spin-spin coupling has so far been restricted to interactions between individual spins and microwave photons [1,2,3]. We demonstrate resonant microwave-mediated coupling between two electron spins that are physically separated by more than 4 mm [4]. Our results imply that microwave-frequency photons may be used as a resource to generate long-range two-qubit gates between spatially separated spins.

[1] Mi et al., Nature 555, 599 (2018)
[2] Samkharadze et al., Science 359, 1123 (2018)
[3] Landig et al., Nature 560, 179 (2018)
[4] Borjans et al., arXiv:1905.00776 (2019)