dorsal/arxiv
View SchemaDynamical parameter estimation using realistic photodetection
| Authors | P. Warszawski, Jay Gambetta, H. M. Wiseman |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0401074 |
| URL | https://arxiv.org/abs/quant-ph/0401074 |
| DOI | 10.1103/PhysRevA.69.042104 |
| Journal | Phys. Rev. A 69, 042104 (2004) |
Abstract
We investigate the effect of imperfections in realistic detectors upon the problem of quantum state and parameter estimation by continuous monitoring of an open quantum system. Specifically, we have reexamined the system of a two-level atom with an unknown Rabi frequency introduced by Gambetta and Wiseman [Phys. Rev. A 64, 042105 (2001)]. We consider only direct photodetection and use the realistic quantum trajectory theory reported by Warszawski, Wiseman, and Mabuchi [Phys. Rev. A 65, 023802 (2002)]. The most significant effect comes from a finite bandwidth, corresponding to an uncertainty in the response time of the photodiode. Unless the bandwidth is significantly greater than the Rabi frequency, the observer's ability to obtain information about the unknown Rabi frequency, and about the state of the atom, is severely compromised. This result has implications for quantum control in the presence of unknown parameters for realistic detectors, and even for ideal detectors, as it implies that most of the information in the measurement record is contained in the precise timing of the detections.
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"abstract": "We investigate the effect of imperfections in realistic detectors upon the\nproblem of quantum state and parameter estimation by continuous monitoring of\nan open quantum system. Specifically, we have reexamined the system of a\ntwo-level atom with an unknown Rabi frequency introduced by Gambetta and\nWiseman [Phys. Rev. A 64, 042105 (2001)]. We consider only direct\nphotodetection and use the realistic quantum trajectory theory reported by\nWarszawski, Wiseman, and Mabuchi [Phys. Rev. A 65, 023802 (2002)]. The most\nsignificant effect comes from a finite bandwidth, corresponding to an\nuncertainty in the response time of the photodiode. Unless the bandwidth is\nsignificantly greater than the Rabi frequency, the observer\u0027s ability to obtain\ninformation about the unknown Rabi frequency, and about the state of the atom,\nis severely compromised. This result has implications for quantum control in\nthe presence of unknown parameters for realistic detectors, and even for ideal\ndetectors, as it implies that most of the information in the measurement record\nis contained in the precise timing of the detections.",
"arxiv_id": "quant-ph/0401074",
"authors": [
"P. Warszawski",
"Jay Gambetta",
"H. M. Wiseman"
],
"categories": [
"quant-ph"
],
"doi": "10.1103/PhysRevA.69.042104",
"journal_ref": "Phys. Rev. A 69, 042104 (2004)",
"title": "Dynamical parameter estimation using realistic photodetection",
"url": "https://arxiv.org/abs/quant-ph/0401074"
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