Reconsidering Rapid Qubit Purification by Feedback
| dc.creator | Wiseman, H. M. | |
| dc.creator | Ralph, J. F. | |
| dc.date | 2006-03-08 | |
| dc.date | 2006-05-13 | |
| dc.date.accessioned | 2026-07-07T07:07:58Z | |
| dc.date.available | 2026-07-07T07:07:58Z | |
| dc.description | This paper reconsiders the claimed rapidity of a scheme for the purification of the quantum state of a qubit, proposed recently in Jacobs 2003 Phys. Rev. A67 030301(R). The qubit starts in a completely mixed state, and information is obtained by a continuous measurement. Jacobs' rapid purification protocol uses Hamiltonian feedback control to maximise the average purity of the qubit for a given time, with a factor of two increase in the purification rate over the no-feedback protocol. However, by re-examining the latter approach, we show that it mininises the average time taken for a qubit to reach a given purity. In fact, the average time taken for the no-feedback protocol beats that for Jacobs' protocol by a factor of two. We discuss how this is compatible with Jacobs' result, and the usefulness of the different approaches. | |
| dc.description | 11 pages, 3 figures. Final version, accepted for publication in New J. Phys | |
| dc.identifier | https://arxiv.org/abs/quant-ph/0603062 | |
| dc.identifier | http://arxiv.org/abs/quant-ph/0603062 | |
| dc.identifier | New J. Phys. 8 (2006) 90 | |
| dc.identifier | doi:10.1088/1367-2630/8/6/090 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/110588 | |
| dc.subject | Quantum Physics | |
| dc.title | Reconsidering Rapid Qubit Purification by Feedback | |
| dc.type | text |