Spin Mechanics in the Strong Coupling

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The ability to prepare a macroscopic mechanical oscillator in a non classical state would have dramatic implications, both at the fundamental level, by upgrading our knowledge of the boundary between classical and quantum physics, and on a more applied point of view, by using the potentially long coherence time of state of the art mechanical oscillators as quantum memories in a quantum information experiment. If alternatives exist, the direct coupling of a spin platform to a mechanical oscillator is one of the most advanced route to reach such milestone. So far, the strong coupling regime, characterized by a spin mechanical exchange rate above both the mechanical and the spin decoherence rates, has not been attained except in GigaHertz frequency mechanical oscillators coupled to superconducting qubits. Among spin platforms, Nitrogen Vacancy centers in diamond offer very long coherence times and a large optical transition. Immersed in a strong magnetic gradient bias, their energy splitting depends on their position, creating the spin-mechanical interface. Among mechanical oscillators, silicon carbide nanowires offer very low masses and therefore an extremely high force sensitivity, which is of prior interest to measure the very low force induced by a single spin flip to a magnet attached to its tip. Spin MEchanics in the Strong Coupling (SMESC) will build a cryogenic spin mechanical coupling platform with a NV center host and a silicon carbide nanowire functionalized with a nanomagnet. It will demonstrate the first operation of such platform in the strong coupling regime by performing a single shot readout of the spin state by reading the position of the mechanical oscillator.