dorsal/arxiv
View SchemaComplexity of decoupling and time-reversal for n spins with pair-interactions: Arrow of time in quantum control
| Authors | Dominik Janzing, Pawel Wocjan, Thomas Beth |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0106085 |
| URL | https://arxiv.org/abs/quant-ph/0106085 |
| DOI | 10.1103/PhysRevA.66.042311 |
| Journal | Phys. Rev. A 66, 042311, 2002 |
Abstract
Well-known Nuclear Magnetic Resonance experiments show that the time evolution according to (truncated) dipole-dipole interactions between n spins can be inverted by simple pulse sequences. Independent of n, the reversed evolution is only two times slower than the original one. Here we consider more general spin-spin couplings with long range. We prove that some are considerably more complex to invert since the number of required time steps and the slow-down of the reversed evolutions are necessarily of the order n. Furthermore, the spins have to be addressed separately. We show for which values of the coupling parameters the phase transition between simple and complex time-reversal schemes occurs.
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"abstract": "Well-known Nuclear Magnetic Resonance experiments show that the time\nevolution according to (truncated) dipole-dipole interactions between n spins\ncan be inverted by simple pulse sequences. Independent of n, the reversed\nevolution is only two times slower than the original one. Here we consider more\ngeneral spin-spin couplings with long range. We prove that some are\nconsiderably more complex to invert since the number of required time steps and\nthe slow-down of the reversed evolutions are necessarily of the order n.\nFurthermore, the spins have to be addressed separately. We show for which\nvalues of the coupling parameters the phase transition between simple and\ncomplex time-reversal schemes occurs.",
"arxiv_id": "quant-ph/0106085",
"authors": [
"Dominik Janzing",
"Pawel Wocjan",
"Thomas Beth"
],
"categories": [
"quant-ph"
],
"doi": "10.1103/PhysRevA.66.042311",
"journal_ref": "Phys. Rev. A 66, 042311, 2002",
"title": "Complexity of decoupling and time-reversal for n spins with pair-interactions: Arrow of time in quantum control",
"url": "https://arxiv.org/abs/quant-ph/0106085"
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