Decoherence of quantum local fisher and uncertainty information in two-qubit NV centers

Abstract

This study aims to investigate the decoherence of the quantum correlation dynamics of two qubit nitrogen-vacancy (NV) centres through local quantum uncertainty (LQU), local quantum Fisher information (LQFI), and concurrence. Using an intrinsic decoherence model, our study investigates how increasing zero-field splitting, external magnetic fields, external electric control fields, dipole-dipole coupling and decoherence affect the generated correlations between two NV centers. It is shown that the system with two nitrogen-vacancy centres can generate strong correlations with certain parameters of zero-field splitting, external magnetic fields, external electric control fields and dipole-dipole coupling. With weak intrinsic decoherence, the generated LQFI, LQU and concurrence exhibit oscillating generations with the same frequency. Most of the time, LQFI and LQU exhibit the same Wigner-Yanase-Fisher correlation, except during strong entanglement intervals. Furthermore, the ability of interactions within a two-qubit system of NV centers to generate two-qubit correlations is weakened by increasing external magnetic fields and zero-field splitting fields. Conversely, increasing external electric control fields and dipole-dipole couplings strengthen the ability of the interactions to generate correlations. Finally, we investigated how an increase in intrinsic decoherence coupling significantly degrades the generated correlations. We also investigated how increasing the external magnetic field, the external electric control field and the dipole-dipole coupling significantly affects these correlation degradations.

Keywords: Concurrence; Local quantum Fisher information; Local quantum uncertainty; Two NV centers.

Fig. 1

The dynamics of LQFI, LQU, and concurrence for two NV-center qubits are illustrated under the following parameter settings: gyromagnetic factor , inter-qubit distance , external magnetic field , external control electric field , and dipole-dipole interaction strength for different zero-field splitting strengths and in (a), and in (b). The intrinsic decoherence is taken with a small coupling: .

Fig. 2

The dynamics of LQFI, LQU, and concurrence for two NV-center qubits of Fig.(1a) are shown but for different external magnetic field couplings: in (a), in (b).

Fig. 3

The dynamics of LQFI, LQU, and concurrence for two NV-center qubits of Fig.(1a) are shown but when increasing the external control electric field coupling to be in (a), and in (b).

Fig. 4

The dynamics of LQFI, LQU, and concurrence for two NV-center qubits of Fig.(1a) are shown but for different dipole-dipole couplings: in (a), and in (b).

Fig. 5

The dynamics of LQFI, LQU, and concurrence for two NV-center qubits of Fig.1a are shown when the intrinsic decoherence is taken with a large coupling in (a), and in (b).

Fig. 6

Two-NV-center-qubits LQFI, LQU, and concurrence dynamics of Figs.2a, 3a, 4a are shown but when the intrinsic decoherence is taken with large coupling: , respectively.