Enhancing the estimation precision of an unknown phase shift in multipartite Glauber coherent states via skew information correlations and local quantum Fisher information

Abstract

Local quantum uncertainty (LQU) and local quantum Fisher information (LQFI) are both tools used to capture purely quantum correlations in multipartite quantum systems. In this paper, we study these quantifiers in the case of multipartite Glauber coherent states, which include the Greenberger–Horne–Zeilinger and Werner states. We perform a comparative study between LQFI and LQU in an isolated system. By using the Kraus operator representation, we study the behavior of these quantifiers on the dephasing channel to investigate their performances under the decoherence effect. In addition, the robustness to the decoherence effect of these two quantifiers is studied. We further examine the situation involving the multipartite Glauber coherent state to decide the sensitivity of the probe state as a resource for quantum estimation protocols.

Local quantum Fisher information and local quantum uncertainty for general X states

“…The behavior of LQFI and LQU in various specific two-qubit systems was considered by many researchers [28,29,30,31,32,33,34,35,36,37,38]. In the previous paper [39], the behavior of LQU and LQFI (together with the entropic discord) was studied on the example of Bell-diagonal states, which are a subclass of X states and allow to include both DM and KSEA interactions but without Zeeman's terms.…”

Thermal local Fisher information and quantum uncertainty in Heisenberg model

“…The non-classical correlations of the LQU and LQFI have been quantified in a two-qubit Heisenberg XYZ model with noise [27], as well as in two-qubit XXZ model [28]. Skew correlations and local quantum Fisher information have been employed to improve the estimate precision of an unknown phase shift in multipartite Glauber coherent states [29]. Nonclassical correlations, of LQFI and LQU, have been investigated in a two-qubit Ising model with an arbitrary magnetic field [30].…”