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TT: Fachverband Tiefe Temperaturen
TT 66: Spintronics / Quantum Information: Vacancies in Diamond and SiC (jointly with HL)
TT 66.10: Vortrag
Freitag, 15. März 2013, 12:00–12:15, H14
Coherent Control of a 13C NV− center — •Burkhard Scharfenberger1, William J. Munro2, and Kae Nemoto1 — 1National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430, Japan — 2NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan
We investigate the theoretically achievable fidelities for coherently controlling an effective three qubit system consisting of a negatively charged NV center in diamond coupling via an hyperfine interaction to one nearby 13C nuclear spin using only micro- and radio wave pulses. With its long coherence times and comparatively simple optical accessibility, already the ’bare’ NV− center has an interesting potential in quantum computing related applications. Although a number of experiments have already been conducted using NV centers with one or more 13C nearby, fidelities achieved are limited not only by experimental inaccuracies but a lack of theoretical understanding of the system dynamics. We seek to redress this by fully modelling the NVC systems behaviour in the ground state manifold, including all hyperfine interactions (between N and V as well as C and V) and dissipation where parameters are taken from previous experimental work as well as theoretical ab-initio studies. We show that for close-by carbons, the strong hyperfine interaction leads to unwanted mixing of levels which ultimately limits fidelities in single-qubit driving and entanglement generation to less than 99% in the experimentally interesting weak magnetic fields regime.