Abstract
A practical implementation of a quantum computer requires robust qubits that are protected against their noisy environment. Dynamical decoupling techniques have been successfully used in the past to offer protected high-fidelity gate operations in negatively-charged Nitrogen-Vacancy (NV-) centers in diamond, albeit under specific conditions with the intrinsic nitrogen nuclear spin initialised. In this work, we show how the SMART protocol, an extension of the dressed-qubit concept, can be implemented for continuous protection to offer Clifford gate fidelities compatible with fault-tolerant schemes, whilst prolonging the coherence time of a single NV- qubit at room temperature. We show an improvement in the average Clifford gate fidelity from for the bare qubit to for the SMART qubit, with the nitrogen nuclear spin in a random orientation. We further show a 30 times improvement in the qubit coherence times compared to the bare qubit.