2005/10/31 by Jonathan Baugh, Osama Moussa, Colm A. Ryan +4 · 1 citation
Chemistry · Materials Science · Mathematics · Physics and Astronomy · #Advanced NMR Techniques and Applications #Chemistry #Dephasing #Hamiltonian (control theory) #Homonuclear molecule #Intermolecular force #Mathematics #Molecule #Nuclear magnetic resonance #Physics #Quantum #Quantum and electron transport phenomena #Quantum information #Quantum mechanics #Quantum state #Quantum system #Qubit #Solid-state spectroscopy and crystallography #quant-ph
paper · pdf · doi:10.1103/physreva.73.022305
11 pages, 8 figures, submitted to PRA; revised version has significant changes to section V, minor changes throughout, and added several references
arxiv created 2005/11/22 · openalex publication_date 2006/02/02 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A three-qubit 13C solid-state nuclear magnetic resonance (NMR) system for quantum-information processing, based on the malonic acid molecule, is used to demonstrate high-fidelity universal quantum control via strongly modulating radio-frequency pulses. This control is achieved in the strong-coupling regime, in which the time scales of selective qubit addressing and of two-qubit interactions are comparable. State evolutions under the internal Hamiltonian in this regime are significantly more complex, in general, than those of typical liquid-state NMR systems. Moreover, the transformations generated by the strongly modulating pulses are shown to be robust against the types of ensemble inhomogeneity that dominate in the employed molecular crystal system. The secondary focus of the paper is upon detailed characterization of the malonic acid system. The internal Hamiltonian of the qubits is determined through spectral simulation. A pseudopure state preparation protocol is extended to make a precise measurement of the dephasing rate of a three-quantum coherence state under residual dipolar interactions. The spectrum of intermolecular 13C--13C dipolar fields in the crystal is simulated, and the results compared with single-quantum dephasing data obtained using appropriate refocusing sequences. We conclude that solid-state NMR systems tailored for quantum-information processing have excellent potential for extending the investigations begun in the liquid-state systems to a greater number of qubits.