Coherent Manipulation of a Silicon Spin-Charge Hybrid Qubit

The recently proposed quantum dot hybrid qubit enables fast, coherent quantum operations [1, 2]. We demonstrate rotations of a hybrid qubit in a three-electron Si/SiGe double quantum dot about two axes of the Bloch sphere (X and Z). We perform Larmor oscillations (x-rotations on the Bloch sphere) between the 0 and 1 hybrid states, demonstrating a T2* time of 2.1 ns at the charge degeneracy point [3,4]. Using tailored pulse gating sequences, we perform fast (\textgreater 10GHz) phase (z-axis) rotations of the hybrid qubit states. We measure a lower bound of the coherence time T$_{2}$* of 10 ns and high figure of merit \textgreater 150. This work was supported in part by ARO (W911NF-12-0607) and the United States Department of Defense. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressly or implied, of the US Government. \\[4pt] [1] Z. Shi, et al., Phys. Rev. Lett. 108, 140503 (2012).\\[0pt] [2] Teck Seng Koh, et al, Phys. Rev. Lett. 109, 250503 (2012)\\[0pt] [3] Z. Shi, et al., Phys. Rev. B 88, 075416 (2013) \\[0pt] [4] Z. Shi, et al., e-print: http://arxiv.org/abs/1308.0588