dorsal/arxiv
View SchemaBoundary of Quantum Evolution under Decoherence
| Authors | N. Khaneja, B. Luy, S. J. Glaser |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0302060 |
| URL | https://arxiv.org/abs/quant-ph/0302060 |
| DOI | 10.1073/pnas.2134111100 |
Abstract
Relaxation effects impose fundamental limitations on our ability to coherently control quantum mechanical phenomena. In this letter, we establish physical limits on how closely can a quantum mechanical system be steered to a desired target state in the presence of relaxation. In particular, we explicitly compute the maximum coherence or polarization that can be transferred between coupled nuclear spins in the presence of very general decoherence mechanisms that include cross-correlated relaxation. We give analytical expressions for the control laws (pulse sequences) which achieve these physical limits and provide supporting experimental evidence. Exploitation of cross-correlation effects has recently led to the development of powerful methods in NMR spectroscopy to study very large biomolecules in solution. We demonstrate with experiments that the optimal pulse sequences provide significant gains over these state of the art methods, opening new avenues for spectroscopy of much larger proteins. Surprisingly, in spite of very large relaxation rates, optimal control can transfer coherence without any loss when cross-correlated relaxation rates are tuned to auto-correlated relaxation rates.
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"abstract": "Relaxation effects impose fundamental limitations on our ability to\ncoherently control quantum mechanical phenomena. In this letter, we establish\nphysical limits on how closely can a quantum mechanical system be steered to a\ndesired target state in the presence of relaxation. In particular, we\nexplicitly compute the maximum coherence or polarization that can be\ntransferred between coupled nuclear spins in the presence of very general\ndecoherence mechanisms that include cross-correlated relaxation. We give\nanalytical expressions for the control laws (pulse sequences) which achieve\nthese physical limits and provide supporting experimental evidence.\nExploitation of cross-correlation effects has recently led to the development\nof powerful methods in NMR spectroscopy to study very large biomolecules in\nsolution. We demonstrate with experiments that the optimal pulse sequences\nprovide significant gains over these state of the art methods, opening new\navenues for spectroscopy of much larger proteins. Surprisingly, in spite of\nvery large relaxation rates, optimal control can transfer coherence without any\nloss when cross-correlated relaxation rates are tuned to auto-correlated\nrelaxation rates.",
"arxiv_id": "quant-ph/0302060",
"authors": [
"N. Khaneja",
"B. Luy",
"S. J. Glaser"
],
"categories": [
"quant-ph"
],
"doi": "10.1073/pnas.2134111100",
"title": "Boundary of Quantum Evolution under Decoherence",
"url": "https://arxiv.org/abs/quant-ph/0302060"
},
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