Experimental control of a nuclear spin quantum register in diamond with decoherence-protected gates

Nuclear spins are one of the most promising candidates for long-lived quantum bits that store and process quantum information. Individual nuclear spins in diamond have been addressed using the nearby electron spin of a nitrogen vacancy center. However, the relatively fast decoherence of the electron spin limits coherent control to the nearest, strongly coupled, nuclear spins. Here, we employ decoherence-protected gates [1] to access individual spins embedded in a bath of nuclear spins that are weakly coupled to an electron spin [2]. We demonstrate the initialization, control and readout of the nuclear spins and discuss our recent progress in implementing two-qubit entangling operations between nuclear spins. These results greatly extend the number of available quantum bits in diamond and provide a way towards tomography with single nuclear spin sensitivity even in decohering environments. [1] T. van der Sar et al., Nature 484, 82 (2012). [2] T. H. Taminiau et al., Phys. Rev. Lett. 109, 137602 (2012).