Regensburg 2013 – wissenschaftliches Programm

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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.