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Hamiltonian engineering with constrained optimization for quantum sensing and control

MetadataDetails
Publication Date2019-01-23
JournalNew Journal of Physics
AuthorsMichael O’Keeffe, Lior Horesh, John F. Barry, Danielle Braje, Isaac L. Chuang
InstitutionsMassachusetts Institute of Technology, MIT Lincoln Laboratory
Citations16

While quantum devices rely on interactions between constituent subsystems and\nwith their environment to operate, native interactions alone often fail to\ndeliver targeted performance. Coherent pulsed control provides the ability to\ntailor effective interactions, known as Hamiltonian engineering. We propose a\nHamiltonian engineering method that maximizes desired interactions while\nmitigating deleterious ones by conducting a pulse sequence search using\nconstrained optimization. The optimization formulation incorporates pulse\nsequence length and cardinality penalties consistent with linear or integer\nprogramming. We apply the general technique to magnetometry with solid state\nspin ensembles in which inhomogeneous interactions between sensing spins limit\ncoherence. Defining figures of merit for broadband Ramsey magnetometry, we\npresent novel pulse sequences which outperform known techniques for homonuclear\nspin decoupling in both spin-1/2 and spin-1 systems. When applied to nitrogen\nvacancy (NV) centers in diamond, this scheme partially preserves the Zeeman\ninteraction while zeroing dipolar coupling between negatively charged\nNV$^{\text -}$ centers. Such a scheme is of interest for NV$^\text{-}$\nmagnetometers which have reached the NV$^\text{-}$-NV$^\text{-}$ coupling\nlimit. We discuss experimental implementation in NV ensembles, as well as\napplicability of the current approach to more general spin bath decoupling and\nsuperconducting qubit control.\n