Dynamics of trade-off relations between quantum information resources in two qubits interacting individually and nonlinearly with a cavity: Decoherence model
The dynamics of trade-off relations between quantum information resources are investigated in a system of two non-interacting qubits, each individually and nonlinearly coupled to coherent cavity fields through intensity-dependent coupling. The qubits are initially prepared in a maximally entangled Bell state, while the cavity fields are assumed to be in coherent states. An exact analytical treatment of the reduced two-qubit density matrix is presented under qubit–cavity detuning and intrinsic decoherence governed by the Milburn model. The time evolutions of first-order coherence, concurrence, intrinsic concurrence and purity are analyzed to elucidate the redistribution of quantum resources. The results confirm that intrinsic concurrence and first-order coherence obey a complementary trade-off relation governed by the purity of the two-qubit state, with standard concurrence acting as a lower bound for intrinsic concurrence throughout the dynamics. The roles of the initial coherent field intensity, qubit–cavity detuning and intrinsic decoherence are examined, showing that nonlinear atom–cavity interactions induce regular oscillatory behavior accompanied by entanglement sudden death and revival phenomena. Increasing the coherent field intensity enhances coherence generation and accelerates entanglement degradation of the generated two-qubit states.
The dynamics of trade-off relations between quantum information resources are investigated in a system of two non-interacting qubits, each individually and nonlinearly coupled to coherent cavity fields through intensity-dependent coupling. The qubits are initially prepared in a maximally entangled Bell state, while the cavity fields are assumed to be in coherent states. An exact analytical treatment of the reduced two-qubit density matrix is presented under qubit–cavity detuning and intrinsic decoherence governed by the Milburn model. The time evolutions of first-order coherence, concurrence, intrinsic concurrence and purity are analyzed to elucidate the redistribution of quantum resources. The results confirm that intrinsic concurrence and first-order coherence obey a complementary trade-off relation governed by the purity of the two-qubit state, with standard concurrence acting as a lower bound for intrinsic concurrence throughout the dynamics. The roles of the initial coherent field intensity, qubit–cavity detuning and intrinsic decoherence are examined, showing that nonlinear atom–cavity interactions induce regular oscillatory behavior accompanied by entanglement sudden death and revival phenomena. Increasing the coherent field intensity enhances coherence generation and accelerates entanglement degradation of the generated two-qubit states.
Abstract In this study, we have applied the intrinsic decoherence (ID) model of the Milburn equation to investigate the temporal evolution of various quantum resources (steerability, entanglement, and coherence) in the generated dipole-coupled two-qubit states. Einstein–Podolsky–Rosen steering, EOF, and Jensen–Shannon divergence are used to analyze these quantum resources. We consider two dipole-coupled qubit interacting with two spatially separated cavities with nonlinear photonic transitions, filled with a superposition of generalized Barut–Girardello coherent fields. The exploration of steerability, entanglement, and coherence has been carried out by considering the nonlinearity of qubit–cavity interactions, the nonclassicality of the superposition of Barut–Girardello coherent fields, the dipole–dipole coupling, and the ID of qubit–cavity interactions. Our results show that the nonlinearity of qubit–cavity interactions, the initial generalized Barut–Girardello coherent states, and the qubit–cavity detuning significantly enhance the generation of quantum steerability, entanglement, and coherence. The dynamics of entanglement and steerability are consistent with the hierarchy principle. The ID effect reduces the amplitudes and frequencies of the generated quantum resources to their stationary values. It is found that the phenomena of sudden steerability arising and sudden annihilation of entanglement are influenced by the initial non-classicality, dipole coupling, and intrinsic qubit–cavity decoherence. Moreover, the strong decoherence and dipole coupling significantly enhance the steady-state values of steerability, entanglement, and coherence.
Abstract We investigate dissipation-induced trade-offs between nonlocal entanglement and local quantum coherence in a two-qubit system coupled to an open superconducting cavity. Using concurrence C , intrinsic concurrence, and the total first-order coherence ( FOC ) of the reduced two-qubit state, we examine how the initial distribution angle, coherent-field intensity, and spontaneous-emission damping redistribute quantum resources during the system evolution. We find that increasing the damping rate and coherent-field intensity suppresses entanglement generation and revivals, whereas the FOC can remain finite over a wide range of parameters. Within this open-system description, the purity of the two-qubit state (or equivalently its mixedness) provides an effective budget that governs the competition between coherence and entanglement in the dynamics. Our results provide a clear physical picture of how dissipation reshapes the balance between local coherence and nonlocal quantum correlations in realistic qubit-cavity platforms, highlighting the relative robustness of coherence compared to entanglement under environmental interactions.
In a system of two charge-qubits that are initially prepared in a maximally entangled Bell's state, the dynamics of quantum memory-assisted entropic uncertainty, purity, and negative entanglement are investigated. Isolated external cavity fields are considered in two different configurations: coherent-even coherent and even coherent cavity fields. For different initial cavity configurations, the temporal evolution of the final state of qubits and cavities is solved analytically. The effects of intrinsic decoherence and detuning strength on the dynamics of bipartite entropic uncertainty, purity and entanglement are explored. Depending on the field parameters, nonclassical correlations can be preserved. Nonclassical correlations and revival aspects appear to be significantly inhibited when intrinsic decoherence increases. Nonclassical correlations stay longer and have greater revivals due to the high detuning of the two qubits and the coherence strength of the initial cavity fields. Quantum memory-assisted entropic uncertainty and entropy have similar dynamics while the negativity presents fewer revivals in contrast.
This paper investigates the intrinsic decoherence effect on quantum memory and coherence dynamics of two dipole-coupled qubits in a non-degenerate bimodel cavity. Entropic uncertainty, entropy, and concurrence are utilized to examine the dynamics of quantum-memory-assisted entropic uncertainty relations, mixedness, and entanglement. The results indicate that the nonlinear interactions between the two qubits and the cavity generate quantum-memory-assisted entropic uncertainty, mixedness, and entanglement, which are reliant not only on the qubit–qubit interaction but also on the intrinsic decoherence and coherence intensity of the initial two-mode cavity states. For specific values of the dipole–dipole interaction, non-classical correlations can be enhanced By reducing the initial intensity coherence, the stability of the quantum memory-assisted entropic uncertainty relations, as well as the two-qubit mixedness of the intrinsic decoherence, are accelerated.
This work investigates the trade-off relations between intrinsic concurrence, concurrence, first-order coherence, and total purity for generated two-qubit Heisenberg XYZ states due to spin–spin interactions supported by spin–orbit interactions in the x and y directions with an external inhomogeneous magnetic field in the x direction by using the Milburn model of intrinsic decoherence. We apply the complementary trade-off relations between quantum resource quantifiers when the two-spin Heisenberg XYZ interactions start with a maximally pure state ( | 1 A 〉 ⊗ | 1 B 〉 ) and a maximally entangled state ( 1 2 [ | 1 A 〉 ⊗ | 1 B 〉 + | 0 A 〉 ⊗ | 0 B 〉 ] ) . The results of the trade-off relations provide a reliable theoretical basis for the mutual transformation between quantum resource quantifiers. It is shown that the spin–spin-Heisenberg XYZ and x , y -spin–orbit interactions have a high capability to generate entanglement and degrade coherence with oscillatory evolutions. The amplitudes and frequencies of the oscillations of the information resources depend on the increase of the applied external inhomogeneous magnetic field, the spin–orbit interactions, and the intrinsic two-spin decoherence. It is found that the stationary quantum information resources generated by intrinsic decoherence depend on the spin–spin, spin–orbit interactions as well as on the applied external inhomogeneous magnetic field in the x -direction.
This study investigates two-qubit local quantum Fisher information correlation (LQFI), entanglement of formation (EoF), and two-qubit Jensen–Shannon coherence as a result of cavity–qubit coupling via intensity dependent and qubit–qubit interactions. Initially, the cavity is filled with coherent and even coherent fields, and the two-qubit state is pure. The cavity–qubit intensity dependent interaction, in the presence of intrinsic decoherence, can produce two-qubit local quantum Fisher information, entanglement of formation, and Jensen–Shannon coherence. This ability depends on dipole–qubit interactions, intrinsic decoherence, and initial cavity sates. The phenomena of sudden changes emerge in the dynamics behavior of the local quantum Fisher information, whereas the phenomenon of sudden birth–death occurs during the entanglement of formation dynamics. These phenomena can be enhanced by modifying the initial coherent field parameters, the mean photon number, and the non-classicality. The dipole qubit–qubit interaction improves the generated two-qubit correlation and coherence, while intrinsic decoherence decreases and stabilizes the generated two-qubit correlation and coherence. For a small initial coherent field intensity and dipole qubit–qubit interaction, the LQFI and EoF non-local correlations grow while the two-qubit Jensen–Shannon coherence diminishes. The qubit–qubit interaction coupling and the initial coherent field intensity can improve the produced stationary LQFI and EoF correlations and Jensen–Shannon coherence in the presence of the intrinsic decoherence.