Proposal for a spin network using a qubit in diamond-peptide unit cell*

Synthetic peptides can nowadays be custom-tailored to one's needs to the extent that it is possible to determine their exact length and structure. Using such rather simple molecules, we propose using them, together with a qubit, in the form of a single nitrogen-vacancy center in diamond being the read-out platform, as the basic unit cell in a conceivable molecular quantum spin network.
We demonstrate the features of this unit cell by presenting a detailed characterization of the different dipolar couplings between the qubit and a doubly-labeled polyproline molecule. Finally, we propose several schemes by which we envision applications for such a spin network, e.g. the understanding of the flow of information across a one-dimensional chain and the realization of a quantum critical point within such a network.