C2QA Quantum Thursdays - Nathalie de Leon

Engineering coherent systems is a central goal of quantum science and quantum information processing. Point defects in diamond known as color centers are a promising physical platform. I will present two recent results that demonstrate how carefully tailoring the diamond host can open new opportunities in quantum science. First, we have developed new methods to control the diamond Fermi level in order to stabilize a new color center, the neutral charge state of the silicon vacancy (SiV) center which combines optical and spin coherence, making it a promising candidate for quantum networks. Second, color centers placed close to the diamond surface can be used for nanoscale sensing and imaging. I will describe our recent efforts to stabilize NV centers within 5 nm of the surface using new surface processing and termination techniques. In fact, many platforms for quantum technologies are limited by noise and loss arising from uncontrolled defects at surfaces and interfaces. Our approach for correlating materials techniques with single qubit measurements to realize directed improvements is generally applicable to many systems, and I will describe our recent efforts to tackle noise and microwave losses in superconducting qubits