Abstract We study the quantumness of gravitational cat states in correlated dephasing channels. Our focus is on exploring how classical correlations between successive actions of a dephasing channel influence the decoherence of two gravitational cats (two qubits) at a thermal regime. The results show that the quantum coherence, local quantum Fisher information, and Bell non-locality can be significantly enhanced by augmenting classical correlations throughout the entire duration when the two qubits pass the channel. However, the gravitational interaction and energy gap between states exhibit intricate impacts on the quantum characteristics of gravitational cats. New features are reported that can be significant for both gravitational physics and quantum information processing.
Abstract We study the quantumness of gravitational cat states in correlated dephasing channels. Our focus is on exploring how classical correlations between successive actions of a dephasing channel influence the decoherence of two gravitational cats (two qubits) at a thermal regime. The results show that the quantum coherence, local quantum Fisher information, and Bell non-locality can be significantly enhanced by augmenting classical correlations throughout the entire duration when the two qubits pass the channel. However, the gravitational interaction and energy gap between states exhibit intricate impacts on the quantum characteristics of gravitational cats. New features are reported that can be significant for both gravitational physics and quantum information processing.
We explore the quantum features of two gravitational cats (gravcats) modeled by two qubits, focusing on quantum steerability, concurrence, and geometric quantum discord under varying conditions of gravitational interaction strength, temperature, and excitation energy. We first analyze the system without dephasing effects, revealing that two-way quantum steering occurs at lower temperatures and higher gravitational interaction strengths. As temperature increases, thermal noise reduces steerability, though gravitational effects remain significant, indicating a non-monotonic behavior dependent on energy and mass scales. Furthermore, quantum correlations exhibit a hierarchy, with geometric quantum discord persisting even when steering and entanglement vanish. We then explore the impact of environmental dephasing and classical correlations on the system's dynamics. Our findings demonstrate that classical correlations in correlated dephasing channels can protect quantum resources, enhancing their stability in both Markovian and non-Markovian regimes. This work highlights the intricate interplay between gravitational interactions, thermal effects, and environmental noise in preserving quantum resources.
We investigate how resourceful gravitational cat states are to preserve quantum correlations. In this regard, we explore the dynamics of gravitational cat states under different situations such as thermal, classical stochastic, general decaying, and power-law noisy fields. In particular, the one-way steerability, Bell nonlocality, entanglement, and purity in two qubits are our main focus. We also address the weak measurement protocol on the dynamics of quantum correlations and purity of the state. Our results show that the gravitational cat states have a reliable and better capacity to preserve quantum correlations and remain one of the good resources for the deployment of quantum information processing protocols. Additionally, two independent channels are also employed, and it is observed that only the weaker coupling regimes are effective in preserving quantum correlations. Notably, in terms of non-Markovian dynamics implication, quantum correlations are found to be longer preserved because of the information feedback phenomenon between the system and environment. Finally, we present a brief analysis to extend our gravitational model to include the electrostatic notion, providing insight into the key differences between the considered configurations.
Abstract We investigate how the classical correlations between successive actions of a colored dephasing channel affect the decoherence of a two-qubit system. Our calculation shows that the l 1 norm of coherence, the relative entropy of coherence, and the robustness of coherence can be noticeably enhanced by increasing the strength of classical correlations in the whole time interval during which the two qubits pass through the channel, while the coherence weight is enhanced only when exceeds a critical value. Moreover, in the infinite-time limit, all the coherence measures reach their steady values which are determined only by .
We study the distribution of quantum correlations and basis-independent coherence in a pair of massive particles confined in a double-well potential and coupled through their mutual Newtonian gravitational interaction. Non-classical correlations are characterized using Bures distance of entanglement and quantum discord, while coherence is quantified through the square root of the quantum Jensen--Shannon divergence (QJSD) from the maximally mixed state, yielding a measure that is invariant under arbitrary unitary transformations and is therefore genuinely basis-independent. The total coherence CT decomposes into two operationally distinct contributions: the collective coherence CC, which captures quantum correlations between the two subsystems, and the localized coherence CL, which captures the intrinsic quantum coherence of each individual subsystem. We analyze how temperature T, the gravitational coupling Δ, and the single-particle energy scale w govern the redistribution of coherence between its collective and localized components. Our results show that CL is more robust against thermal fluctuations than CC, and that increasing Δ preferentially enhances collective coherence by strengthening gravitationally induced inter-particle correlations.
Abstract The effects of classical correlations and associated decoherence on the fidelity dynamics of two qubits initially prepared in maximally entangled (ME) and coherent states are examined. In both the Markovian and non-Markovian regimes, the dynamics of fidelity in a correlated dephasing channel is probed. We show that fidelity decreases over time but does not disappear completely, implying that the output state does not become quite dissimilar from the input state under the effects of dephasing correlated channel. The ME state, in comparison, is more tolerant of the dephasing effects of the correlated channel than that of the maximally coherent state. Fidelity of the quantum states is significantly influenced by the degree of classical correlations between successive actions of the channel on the two qubits. As the amount of classical correlations in the implementation of the channel increases, the fidelity of the quantum states can be noticeably enhanced.
In this article, we investigate the hierarchy of quantum correlations between two gravitational cats states (modeled by two qubits). We use concurrence to quantify the entanglement between the two gravitational cat states. Quantum steering is employed to measure the steerabilities. We consider geometric quantum discord to quantify quantum correlations beyond entanglement. We show that the concurrence persists even when steerability is lost under thermal effects. We also show that the temperature influences the degree of quantum correlations between the two gravitational cat states. Besides, when the energy difference between the ground state and the first excited level becomes significant, the states become separable.