dorsal/arxiv
View SchemaDesign of Strongly Modulating Pulses to Implement Precise Effective Hamiltonians for Quantum Information Processing
| Authors | Evan M. Fortunato, Marco A. Pravia, Nicolas Boulant, Grum Teklemariam, Timothy F. Havel, David G. Cory |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0202065 |
| URL | https://arxiv.org/abs/quant-ph/0202065 |
| DOI | 10.1063/1.1465412 |
| Journal | Journal of Chemical Physics 116(17), 7599-7606, 2002 |
Abstract
We describe a method for improving coherent control through the use of detailed knowledge of the system's Hamiltonian. Precise unitary transformations were obtained by strongly modulating the system's dynamics to average out unwanted evolution. With the aid of numerical search methods, pulsed irradiation schemes are obtained that perform accurate, arbitrary, selective gates on multi-qubit systems. Compared to low power selective pulses, which cannot average out all unwanted evolution, these pulses are substantially shorter in time, thereby reducing the effects of relaxation. Liquid-state NMR techniques on homonuclear spin systems are used to demonstrate the accuracy of these gates both in simulation and experiment. Simulations of the coherent evolution of a 3-qubit system show that the control sequences faithfully implement the unitary operations, typically yielding gate fidelities on the order of 0.999 and, for some sequences, up to 0.9997. The experimentally determined density matrices resulting from the application of different control sequences on a 3-spin system have overlaps of up to 0.99 with the expected states, confirming the quality of the experimental implementation.
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"abstract": "We describe a method for improving coherent control through the use of\ndetailed knowledge of the system\u0027s Hamiltonian. Precise unitary transformations\nwere obtained by strongly modulating the system\u0027s dynamics to average out\nunwanted evolution. With the aid of numerical search methods, pulsed\nirradiation schemes are obtained that perform accurate, arbitrary, selective\ngates on multi-qubit systems. Compared to low power selective pulses, which\ncannot average out all unwanted evolution, these pulses are substantially\nshorter in time, thereby reducing the effects of relaxation. Liquid-state NMR\ntechniques on homonuclear spin systems are used to demonstrate the accuracy of\nthese gates both in simulation and experiment. Simulations of the coherent\nevolution of a 3-qubit system show that the control sequences faithfully\nimplement the unitary operations, typically yielding gate fidelities on the\norder of 0.999 and, for some sequences, up to 0.9997. The experimentally\ndetermined density matrices resulting from the application of different control\nsequences on a 3-spin system have overlaps of up to 0.99 with the expected\nstates, confirming the quality of the experimental implementation.",
"arxiv_id": "quant-ph/0202065",
"authors": [
"Evan M. Fortunato",
"Marco A. Pravia",
"Nicolas Boulant",
"Grum Teklemariam",
"Timothy F. Havel",
"David G. Cory"
],
"categories": [
"quant-ph"
],
"doi": "10.1063/1.1465412",
"journal_ref": "Journal of Chemical Physics 116(17), 7599-7606, 2002",
"title": "Design of Strongly Modulating Pulses to Implement Precise Effective Hamiltonians for Quantum Information Processing",
"url": "https://arxiv.org/abs/quant-ph/0202065"
},
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