Quantum Acoustics with Spins in Silicon Carbide – QUASSIC

The degree of control over individual solid-state quantum systems has experienced tremendous progress over the last two decades, opening not only novel prospects in fundamental science but also new horizons in the growing field of quantum technologies. Among all the variety of condensed-matter artificial atoms investigated up to now, electron spins associated with optically-active point-defects in semiconductors presently stand out for their capacity to maintain their quantum characteristics over outstanding long time. One of the present grails in the control of such spin defects is the creation of multi-partite entanglement, in which quantum correlations are shared among numerous spins. In this context, a promising strategy consists in implementing a mediated interaction between remote spins via a quantum interconnecting bus, like visible or microwave photons, or mechanical modes.
The QUASSIC project aims at implementing a novel hybrid quantum interface coupling the spins of point defects to surface acoustic waves. It will capitalize, in a still unexplored manner, on the outstanding properties of spin defects in silicon carbide and the coherent nature of surface acoustic waves, in order to achieve a tailored interaction between spins and acoustic phonons, down to the single spin or single phonon levels. Such platform will enable the control of the spins by the SAW as well as the reciprocal control of the SAW phonons by the spins, up to spin-phonon entanglement in the cavity quantum acousto-dynamics regime.
Such hybrid quantum architecture will open doors to implement a rich variety of acoustic equivalents of quantum optics experiments, in which optical photons are replaced by acoustic phonons. The QUASSIC project holds great promises for the development of on-chip entanglement distribution between remote spins and hybrid quantum interfaces entangling multiple quantum systems like photon-spin-phonon interfaces, with strong potential applications in quantum technologies.