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.
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.
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.
In this paper, we explore distribution dynamics of two-qubit Fisher and skew information correlations of a dissipative microwave cavity field interacting with two charged superconducting qubits. Besides the negativity function, non-classical correlations beyond entanglement are studied using local quantum Fisher information (LQFI) and local quantum uncertainty (LQU). We find that the two-qubit non-classical correlations are sensitive to qubit–qubit distribution angle, two-qubit dissipation parameter, and initial coherent state intensity. The phenomena of frozen quantum correlations, sudden death or birth, as well as revival dynamical maps are feasible in the current two-qubit state when exposed to a microwave cavity. The non-classical correlations and entanglement have been found damped under the two-qubit dissipation appearance in the field. For the increasing strength of coherence intensity of the field, the two-qubit non-classical correlations functions remain to emerge quickly and oscillate with higher frequency, although with the least amplitudes. Interestingly, unlike the non-classical correlations, negativity does not emerge against higher coherence strengths of the cavity and remains completely zero. Finally, for the least dissipation and higher coherence strength, one can readily generate non-classical two-qubit states employing a microwave cavity.
Abstract Quantum coherence represents a basic feature of a quantum system that is not present in the classical world. Here, we explore the dynamic behaviors of quantum coherence in two charge qubits who are strongly coupled with a single-mode dissipative cavity field. The results show that quantum coherence is sensitive to the coupled system parameters including qubit dissipation rate, initial qubit distribution angle, and coherent state intensity of the cavity field. Additionally, during the dynamic evolution, quantum coherence behaves periodically in the case of the qubit distribution angle, and this periodicity depends on the qubit dissipation rate. Also, the increasing coherent state intensity of cavity field can enhance the magnitude of quantum coherence, meaning that coherence resource in dissipative solid state quantum system can be controlled to some extent. This controllable coherence resource in engineering applications may quantify the advantage enabled in the superconducting circuit for processing the remarkable quantum information tasks.
Abstract Entanglement is an essential resource for quantum information processing; however, it is highly susceptible to decoherence induced by environmental interactions. In this work, we investigate the entanglement dynamics of a two-qubit system subjected to Markovian noise and explore the effectiveness of external control fields in preserving quantum correlations. Using the Lindblad master equation, we model the evolution of the system under two decoherence channels, namely, amplitude damping (spontaneous emission) and phase damping (dephasing). We introduce periodic driving and optimal control protocols to mitigate entanglement loss and analyze their impact using concurrence as a quantifier of two-qubit entanglement. Our numerical results reveal certain conditions under which sudden death of entanglement can be delayed or even prevented. Additionally, in the case of the initial state being a mixed state, we identify time regimes where entanglement revival occurs, providing insights into quantum error correction strategies. The results contribute to the broader understanding of quantum coherence preservation and have implications for quantum computing, secure quantum communication, and quantum memory design.
This paper explores the dynamics of two spatially separated superconducting flux qubits, initially in a maximally correlated state, without mutual interaction. The system is modeled using the master intrinsic decoherence equation with the flux-qubits-resonator interaction Hamiltonian. The effects of initial state, detuning, and decoherence on the generated oscillatory correlation dynamics and the sudden death-birth phenomenon of the two flux-qubits entanglement are examined. The results demonstrate that qubit-resonator-qubit interactions have a high ability to generate quantum interferometric power and local quantum uncertainty correlations beyond that of concurrence entanglement.
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.