Scalable arrangements of nitrogen vacancy centers (NV) in diamond remain an open key challenge on the way to e cient quantum information processing, quantum simulation and magnetic sensing applications at the quantum limit. Although technologies based on implanting NV centers in bulk diamond or hybrid device approaches have been developed, they are limited in the achievable spatial resolution or by the
intricate complexity, respectively. Here we provide an alternative solution for creating a scalable system of individually addressable NV centers based on the self-assembling capabilities of biological systems. By using surface functionalized nanodiamonds we propose a new avenue to bridging the bio-nano interface. Taking benefit of the outstanding nanometer resolution of the bio self-assembling techniques together with the controlled creation even of 3-D spatial structures paves the way towards numerous multiqubit applications. We provide a detailed theoretical analysis on the feasibility of multiqubit quantum operations in one and two dimensional nanodiamond arrays, exploiting the signi cant dipolar coupling on the nanometer scale and address the problems of decoherence, imperfect couplings and the randomness of the relative orientations of the NV center symmetry axes. We show that our scheme allows for the high-fi delity creation of entanglement, cluster states and quantum simulation applications. In addition we present first experimental demonstrations of interconnecting nanodiamonds using biological protein complexes.
In summary we have demonstrated a new method to scale up quantum systems based on NV centers by exploiting the ability of biological systems for self-assembly with the precise positioning of nanodiamonds in such structures. We experimentally realized the creation of small nanodiamond clusters as well as first steps towards large ordered arrays. Based on the achievable NV distances on the nanometer scale we theoretically proposed the realization of single and multiqubit gates as well as interesting applications such as the creation of cluster states, addressing the typical problems as the limited coherence time and heterogeneous dipolar coupling strengths. Decoupling fields around 1MHz, well within reach in current experimental setups, together with signi ficant dipolar couplings of several tens of kHz, allow for the effi cient decoupling of nanodiamond surface noise leading to coherence times comparable to the ultimate T1 limit. Thus gate fidelities well above 95% can be expected even for multiple qubits and imperfect couplings. We believe that the combination of nanodiamonds with biological systems provides a promising approach towards scalability overcoming the limitations of current attempts and o ffering a high level of control in both structure formation and qubit addressing.