Entangling spatially separated quantum bits is an important tool for quantum key distribution, quantum sensing, and scalable quantum computing. The negatively charged silicon-vacancy center in diamond (SiV) is unique in its potential for efficient, high-fidelity gates with optical photons, which is the prerequisite for entangling networks of separated quantum bits. We have recently implemented a scheme to entangle SiVs with different optical transition frequencies, overcoming the inhomogeneous distribution common in solid-state optical qubits. Additionally, we have engineered high fidelity gates between the SiV spin and the spin of the
29Si nucleus, which can serve as a long-lasting quantum memory. These two advances present the prospects for entanglement distillation, device-independent quantum key distribution and distributed quantum sensing.
The chemical vapor deposition of diamond is known to introduce complexes of silicon, vacancy, and hydrogen. Here the authors theoretically examine several such complexes, some of which have already been observed, others which could potentially form. Using hybrid density functional theory for the treatment of highly correlated orbitals, many measurable quantities are calculated. The SiV
2H(-) negatively charged defect is found to be a promising candidate for a long lived solid state quantum memory.
In recent years, defect centers in wide band gap semiconductors such as diamond, have received significant attention. Defects offer great utility as single photon emitters, nanoscale sensors, and quantum memories and registers for quantum computation. Critical to the utility of these defects, is their charge state. In this dissertation, experiments surrounding the charge state dynamics and the carrier dynamics are performed and analyzed. Extensive studies of the ionization and recombination processes of defects in diamond, specifically, the Nitrogen Vacancy (NV) center, have been performed. Diffusion of ionized charge carriers has been imaged indirectly through the recapture of said carriers by optically active defects such as the NV center and the Silicon Vacancy (SiV) center. With proper understanding of the carrier dynamics, diamond stands to be a strong competitor in the field of spintronics for quantum information processing. Additionally, the understanding of these charge state dynamics is utilized in a novel proof of principle experiment, showing that the NV center defect’s charge state could serve as an ultra-dense 3D memory platform. The NV center has also been used as a nanoscale magnetometer. The high degree of spin polarization and the ease of manipulation of the NV allows us to transfer this polarization to other spins in the diamond and assists in the detection of spins outside of the diamond. Ensembles of Nitrogen Vacancy centers can be used to perform NMR spectroscopy of sample volumes not achievable through traditional methods. The operating mechanisms of the magnetic resonance aspects of the NV center will be discussed in depth. Work surrounding the control and polarization of the NV center’s host nitrogen spin will be covered. The topic of sensitivity and methods to improve that sensitivity will be covered as well.