dorsal/arxiv
View SchemaRapid state purification protocols for a Cooper pair box
| Authors | E. J. Griffith, C. D. Hill, J. F. Ralph, H. M. Wiseman, Kurt Jacobs |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0610044 |
| URL | https://arxiv.org/abs/quant-ph/0610044 |
| DOI | 10.1103/PhysRevB.75.014511 |
| Journal | Phys. Rev. B 75, 014511 (2007) |
Abstract
We propose techniques for implementing two different rapid state purification schemes, within the constraints present in a superconducting charge qubit system. Both schemes use a continuous measurement of charge (z) measurements, and seek to minimize the time required to purify the conditional state. Our methods are designed to make the purification process relatively insensitive to rotations about the x-axis, due to the Josephson tunnelling Hamiltonian. The first proposed method, based on the scheme of Jacobs [Phys. Rev. A 67, 030301(R) (2003)] uses the measurement results to control bias (z) pulses so as to rotate the Bloch vector onto the x-axis of the Bloch sphere. The second proposed method, based on the scheme of Wiseman and Ralph [New J. Phys. 8, 90 (2006)] uses a simple feedback protocol which tightly rotates the Bloch vector about an axis almost parallel with the measurement axis. We compare the performance of these and other techniques by a number of different measures.
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"abstract": "We propose techniques for implementing two different rapid state purification\nschemes, within the constraints present in a superconducting charge qubit\nsystem. Both schemes use a continuous measurement of charge (z) measurements,\nand seek to minimize the time required to purify the conditional state. Our\nmethods are designed to make the purification process relatively insensitive to\nrotations about the x-axis, due to the Josephson tunnelling Hamiltonian. The\nfirst proposed method, based on the scheme of Jacobs [Phys. Rev. A 67,\n030301(R) (2003)] uses the measurement results to control bias (z) pulses so as\nto rotate the Bloch vector onto the x-axis of the Bloch sphere. The second\nproposed method, based on the scheme of Wiseman and Ralph [New J. Phys. 8, 90\n(2006)] uses a simple feedback protocol which tightly rotates the Bloch vector\nabout an axis almost parallel with the measurement axis. We compare the\nperformance of these and other techniques by a number of different measures.",
"arxiv_id": "quant-ph/0610044",
"authors": [
"E. J. Griffith",
"C. D. Hill",
"J. F. Ralph",
"H. M. Wiseman",
"Kurt Jacobs"
],
"categories": [
"quant-ph",
"cond-mat.supr-con"
],
"doi": "10.1103/PhysRevB.75.014511",
"journal_ref": "Phys. Rev. B 75, 014511 (2007)",
"title": "Rapid state purification protocols for a Cooper pair box",
"url": "https://arxiv.org/abs/quant-ph/0610044"
},
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