Selective Noise Resistant Gate.

Realizing individual control on single qubits in a spin-based quantum register is an ever-increasing challenge due to the close proximity of the qubits resonance frequencies. Current schemes typically suffer from an inherent trade-off between gate fidelity and qubits selectivity. Here, we report on a new scheme which combines noise protection by dynamical decoupling and magnetic gradient based selectivity, to enhance both the fidelity and the selectivity. With single nitrogen vacancy centers in diamond, we experimentally demonstrate quantum gates with a fidelity of about 0.9 and a 50 kHz spectral bandwidth, which is almost an order of magnitude narrower than the unprotected bandwidth. Our scheme will enable selective control of an individual nitrogen vacancy qubit in an interacting qubits array using relatively moderate gradients of about 1 mG/nm.