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arXiv:2608.13493

Quantum correlations and Basis-Independent Coherence Distribution in Two Gravitational Cat States

Mostafa Mansour, Mansoura Oumennana

quant-phSubmitted Aug 13, 2026• Announced Aug 14, 2026• 0 citations
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Abstract

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 $C_T$ decomposes into two operationally distinct contributions: the collective coherence $C_C$, which captures quantum correlations between the two subsystems, and the localized coherence $C_L$, 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 $C_L$ is more robust against thermal fluctuations than $C_C$, and that increasing $Δ$ preferentially enhances collective coherence by strengthening gravitationally induced inter-particle correlations.

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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 CTC_TCT​ decomposes into two operationally distinct contributions: the collective coherence CCC_CCC​, which captures quantum correlations between the two subsystems, and the localized coherence CLC_LCL​, which captures the intrinsic quantum coherence of each individual subsystem. We analyze how temperature TTT, the gravitational coupling ΔΔΔ, and the single-particle energy scale www govern the redistribution of coherence between its collective and localized components. Our results show that CLC_LCL​ is more robust against thermal fluctuations than CCC_CCC​, and that increasing ΔΔΔ preferentially enhances collective coherence by strengthening gravitationally induced inter-particle correlations.
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In recent years, the quantum nature of gravity has attracted significant attention as one of the most important problems in modern physics. Here, we analyze the mechanism of gravitationally-induced entanglement from the perspective of quantum resource theory. Building on the framework of Bose et al. [Phys. Rev. Lett. 119, 240401 (2017)], we show that the gravitational interaction acts as a unitary channel, redistributing quantum resources between two spatially superposed masses. Specifically, we demonstrate that the resulting bipartite entanglement originates from the coherent conversion of local quantum coherence -- initially present in each subsystem -- into shared non-local correlations. We derive exact, analytical complementarity relations quantifying this conversion, link the decay of local coherence directly to the growth of entanglement, and support these findings with numerical simulations. Our results clarify the underlying mechanism and establish gravity as a coherence-to-entanglement conversion channel, offering a refined interpretive basis for forthcoming experimental tests. Crucially, we show that initial coherence is a necessary condition for entanglement generation and that its degree bounds the maximum achievable entanglement, with maximal entanglement requiring initial maximal coherence.
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.
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.
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.