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Quantum frequency estimation with conditional states of continuously monitored independent dephasing channels
- Source :
- Int. J. Quantum Inform. 17, 1941013 (2019)
- Publication Year :
- 2019
-
Abstract
- We discuss the problem of estimating a frequency via N-qubit probes undergoing independent dephasing channels that can be continuously monitored via homodyne or photo-detection. We derive the corresponding analytical solutions for the conditional states, for generic initial states and for arbitrary efficiency of the continuous monitoring. For the detection strategies considered, we show that: i) in the case of perfect continuous detection, the quantum Fisher information (QFI) of the conditional states is equal to the one obtained in the noiseless dynamics; ii) for smaller detection efficiencies, the QFI of the conditional state is equal to the QFI of a state undergoing the (unconditional) dephasing dynamics, but with an effectively reduced noise parameter.<br />Comment: Accepted in Int. J. Quantum Inf. for the special issue related to the conference Quantum 2019, Torino, Italy
- Subjects :
- Quantum Physics
Subjects
Details
- Database :
- arXiv
- Journal :
- Int. J. Quantum Inform. 17, 1941013 (2019)
- Publication Type :
- Report
- Accession number :
- edsarx.1910.12549
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1142/S0219749919410132