Theoretical investigation of the stability of an NV center near the surface and decoherence mechanisms due to bulk and surface impurities

Delaware State University, Dover DE

Investigators

Abstract

NONTECHNICAL SUMMARY The Division of Materials Research and the Division of Human Resource Development contribute funds to this award. It supports theoretical research and education aimed at understanding a particular kind of defect in crystalline diamond where a nitrogen atom replaces a carbon atom and an adjacent carbon atom site is unoccupied. This NV center traps electrons in a small region where they occupy a quantum state with angular momentum - in a sense it appears as though the electronic state is spinning. Control of the quantum state of the NV center is a route to performing computation through the manipulation of quantum mechanical states - quantum computing. The PI aims to study NV center interactions with various impurities and contaminants in diamond. By elucidating how undesirable quantum mechanical effects may be minimized, the research may lead to advances in ultra-high resolution imaging and magnetic field detection. The PI will use formal theoretical methods and computer simulations, to investigate the mechanism of stability and loss of coherence - the deterioration of a quantum state. The resulting models will be compared with the experimental results of collaborators at Harvard and Delaware State University. This award also supports the education of a graduate student and two undergraduate students at Delaware State University, one of the Historically Black Colleges and Universities. The students will benefit from exposure to modeling, mathematical calculations, programming, and data analysis techniques, and will have opportunities to interact with other researchers at the Institute for Theoretical Atomic, Molecular, and Optical Physics at Harvard. The PI will develop a new graduate course incorporating various many-body physics techniques and results from the research. Analysis algorithms developed in this project will be distributed to the greater scientific community through freely available user-developed code libraries. The research results will also be incorporated into a scientific presentation at the Physics Open House, an outreach activity held annually on the Delaware State University campus to promote science in the vicinity. TECHNICAL SUMMARY The Division of Materials Research and the Division of Human Resource Development contribute funds to this award. It supports theoretical research and education aimed to advance understanding and controlling the stability of nitrogen-vacancy (NV) centers due to structural defects and contaminants. The PI aims to develop a theoretical framework for understanding NV center interactions with various impurities and contaminants. The research will concentrate on three specific objectives: (1) Interactions of NV centers having various surface terminations with water molecules covering the surface. The PI will develop a model to calculate the stability of the NV center at various depths from the surface and to predict the probability that the NV center will be neutralized and that a nitrogen atom will migrate to the surface. (2) Interactions with bulk substitutional atom impurities. The PI will determine how the impurity population distribution changes at various implantation energies and temperatures, and will calculate the decoherence rate of a NV spin in a dilute spin bath of substitutional atom impurities. (3) Line broadening in electron spin resonance spectra. Line broadening reduces the sensitivity of magnetic field detection in NV-based devices. The PI will determine the cause of line broadening and will develop a scheme to minimize it. By elucidating how undesirable quantum mechanical effects may be minimized, the present research may lead to advances in ultra-high resolution imaging and magnetic field detection. The PI will use analytical and numerical methods, including computer simulations, to investigate the mechanism of decoherence. The resulting models will be compared with the experimental results of collaborators at Harvard and Delaware State University. This award also supports the education of a graduate student and two undergraduate students at Delaware State University, one of the Historically Black Colleges and Universities. The students will benefit from exposure to modeling, mathematical calculations, programming, and data analysis techniques, and will have opportunities to interact with other researchers at the Institute for Theoretical Atomic, Molecular, and Optical Physics at Harvard. The PI will develop a new graduate course incorporating various many-body physics techniques and results from the research. Analysis algorithms developed in this project will be distributed to the greater scientific community through freely available user-developed code libraries. The research results will also be incorporated into a scientific presentation at the Physics Open House, an outreach activity held annually on the Delaware State University campus to promote science in the vicinity.