The effect of probe-Ohmic environment coupling type and probe information flow on quantum probing of the cutoff frequency

• Published in: Physics letters. A Vol. 383; no. 35; p. 126006
• Main Authors: Salari Sehdaran, Fahimeh, Zandi, Mohammad H., Bahrampour, Alireza
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 16-12-2019
• Subjects: Information flow; Open quantum system; Quantum estimation theory; Quantum probe; Quantum probe; Quantum estimation theory; Information flow; Open quantum system
• ISSN: 0375-9601; 1873-2429
• DOI: 10.1016/j.physleta.2019.126006

This work aims to compare results of dissipating and pure dephasing single-qubit probes in characterizing the cutoff frequency of a harmonic reservoir Ohmic spectral density. In particular, we proved that a dissipating single-qubit improves the estimation precision of the cutoff frequency estimator. The information backflow and outflow of the dissipating and the dephasing single-qubit are compared. The relation between the quantum Fisher information and the information outflow and backflow of the probe is obtained. The results show that difference between the values of information outflow and backflow of a dissipating single-qubit is larger than a dephasing single-qubit. So, a single-qubit probe extracts more information from an Ohmic reservoir by increasing the difference between the values of information outflow and backflow of the probe.
•A dissipating single-qubit improves estimation precision of cutoff frequency.•We found relation between QFI and information flow of the probe.•We showed information out- and backflow difference of dissipating and dephasing qubit.