Decoherence-protected quantum gates for a hybrid solid-state spin register

TitleDecoherence-protected quantum gates for a hybrid solid-state spin register
Publication TypeJournal Article
Year of Publication2012
Authorsvan der Sar T, Wang ZH, Blok MS, Bernien H, Taminiau TH, Toyli DM, Lidar DA, Awschalom DD, Hanson R, Dobrovitski VV
Journal TitleNature
Volume484
Pages82-86
Date Published04
Type of ArticleArticle
ISBN Number0028-0836
Accession NumberWOS:000302343400038
Keywordsbath, coherent dynamics, diamond, electron, memory, nuclear-spin
Abstract

Protecting the dynamics of coupled quantum systems from decoherence by the environment is a key challenge for solid-state quantum information processing(1,2). An idle quantum bit (qubit) can be efficiently insulated from the outside world by dynamical decoupling(3), as has recently been demonstrated for individual solid-state qubits(4-9). However, protecting qubit coherence during a multi-qubit gate is a non-trivial problem(3,10,11): in general, the decoupling disrupts the interqubit dynamics and hence conflicts with gate operation. This problem is particularly salient for hybrid systems(12-22), in which different types of qubit evolve and decohere at very different rates. Here we present the integration of dynamical decoupling into quantum gates for a standard hybrid system, the electron-nuclear spin register. Our design harnesses the internal resonance in the coupled-spin system to resolve the conflict between gate operation and decoupling. We experimentally demonstrate these gates using a two-qubit register in diamond operating at room temperature. Quantum tomography reveals that the qubits involved in the gate operation are protected as accurately as idle qubits. We also perform Grover's quantum search algorithm(1), and achieve fidelities of more than 90% even though the algorithm run-time exceeds the electron spin dephasing time by two orders of magnitude. Our results directly allow decoherence-protected interface gates between different types of solid-state qubit. Ultimately, quantum gates with integrated decoupling may reach the accuracy threshold for fault-tolerant quantum information processing with solid-state devices(1,11).

URL<Go to ISI>://WOS:000302343400038
DOI10.1038/nature10900
Alternate JournalNature