Modulating quantum Fisher information of qubit in dissipative cavity by coupling strength

Abstract

By using the non-Markovian master equation, we investigate the effect of the cavity and the environment on the quantum Fisher information (QFI) of an atom qubit system in a dissipation cavity. We obtain the formulae of QFI for two different initial states and analyze the effect of the atom-cavity coupling and the cavity-reservoir coupling on the QFI. The results show that the dynamic behavior of the QFI is obviously dependent on the initial atomic states, the atom-cavity coupling and the cavity-reservoir coupling. The stronger the atom-cavity coupling, the quicker the QFI oscillates and the slower the QFI reduces. Especially, the QFI will tend to a stable value not zero if the atom-cavity coupling is large enough. On the other hand, the smaller the cavity-reservoir coupling, the stronger the non-Markovian effect, the slower the QFI decay. In other words, choosing the best parameter can improve the accuracy of parameter estimation. In addition, the physical explanation of the dynamic behavior of the QFI is given by means of the QFI flow.

Dynamics of quantum Fisher information in the two-qubit systems constructed from the Yang-Baxter matrices

“…It is well-known that I φ (ρ φ ) < 0 for some t represents the information flow from system to the environment which defines the Markovian regime and the QFI is monotonically decreasing under Markovian dynamics, as it cannot increase under completely positive maps while I φ (ρ φ ) > 0 corresponds to the non-Markovian regime where information flow is from the environment to the system [29,30,46,47,48,49,50]. In this situation, it can be called that QFI witnesses the non-Markovianity of the dynamics of the system.…”

Environmental parameter estimation with the two-level atom probes

“…[24][25][26][27][28][29] However, some studies indicate that not all entangled states are helpful for quantum metrology. [30,31] In reality, the estimation precision of the parameters is unavoidably affected by its environment, and several schemes were proposed to protect the QFI in the structured reservoir, such as using quantum screening, [32] driving multi-particle systems, [33] optimizing the controllable parameters, [34] and combing noknowledge quantum feedback control with quantum weak measurement. [35] The environment is often complex.…”

Based-nonequilibrium-environment non-markovianity, quantum Fisher information and quantum coherence

“…Recently, the influence of environments on the QFI and quantum coherence of quantum systems has become an important research topic. ...... one of our authors have obtained the analytical solution of QFI through the SLD method and have enhanced or retarded the QFI by the dissipation cavity [3]. Very recently, more and more attention has been paid to study the relationship be- * zhmzc1997@hunnu.edu.cn tween different quantum effects.…”

“…Recently, the influence of environments on the QFI and quantum coherence of quantum systems have become an important research topic. In past work, the QFI of quantum systems has been investigated in the Lorentzian [6,[18][19][20] and Ohmic environments [3]. And the quantum coherence of quantum systems is also studied in the Lorentzian or Ohmic environment [17,21,22].…”