Quantum imaginarity is a fundamental quantum resource essential for quantum information processing. In this paper, we investigate the dynamical evolution behavior of quantum imaginarity for tripartite quantum mixed states in Schwarzschild spacetime. We find that Hawking radiation degrades the quantum resource of imaginarity, consistent with the behavior of entanglement and coherence under the Hawking effect. Interestingly, imaginarity exhibits a sharp change in the early stage of Hawking radiation, after which it varies slowly and asymptotically approaches a steady value. We further derive several trade-off relations that characterize the nonlocal redistribution of imaginarity across Rindler horizons. The findings of this study contribute to a deeper understanding of quantum resource behaviors in black hole spacetimes.
Quantum imaginarity is a fundamental quantum resource essential for quantum information processing. In this paper, we investigate the dynamical evolution behavior of quantum imaginarity for tripartite quantum mixed states in Schwarzschild spacetime. We find that Hawking radiation degrades the quantum resource of imaginarity, consistent with the behavior of entanglement and coherence under the Hawking effect. Interestingly, imaginarity exhibits a sharp change in the early stage of Hawking radiation, after which it varies slowly and asymptotically approaches a steady value. We further derive several trade-off relations that characterize the nonlocal redistribution of imaginarity across Rindler horizons. The findings of this study contribute to a deeper understanding of quantum resource behaviors in black hole spacetimes.
Quantum imaginarity, as a critical resource metric for quantifying intrinsic nonreal coherence encoded in quantum states, exhibits nontrivial evolutionary behaviors in curved spacetime backgrounds. This work focuses on bipartite Dirac field reduced states in the quantum atmosphere of a static Schwarzschild black hole, aiming to explore the modulation of three mainstream imaginarity measures by Hawking thermal radiation. We reveal that the relative-entropy imaginarity, the geometric imaginarity and robustness of imaginarity, the fully accessible state presents a valley-shaped radial profile with a local minimum inside the quantum atmosphere, while the cross-coupling and fully inaccessible states follow opposite peak-shaped trends. Further analysis demonstrates that the Hartle-Hawking constant significantly strengthens the redistribution effect of imaginarity across both regions, whereas an increase in the event horizon radius weakens such redistribution and flattens the extremum features. These findings offer a new perspective for decoding the information structure of black hole quantum atmospheres and the intrinsic quantum nature of Hawking radiation.
Black hole spacetimes provide a natural setting for quantum systems in curved spacetime, where effects such as Hawking radiation arise from event horizons. In this work, we investigate the impact of the Hawking effect on quantum imaginarity in Schwarzschild spacetime, focusing on nonlocal advantage of quantum imaginarity (NAQI) and assisted imaginarity distillation. For NAQI, it is significantly affected by Hawking radiation, exhibiting a pronounced difference between physically accessible and inaccessible regions. It is suppressed in the physically accessible region with increasing Hawking temperature and may vanish, while remaining absent in the physically inaccessible region across the parameter regime. For assisted imaginarity distillation, the Hawking effect modifies the assisted fidelity in a state-dependent manner. In the physically accessible region, the fidelity generally decreases with increasing temperature, indicating reduced distillation capability, whereas the physically inaccessible region exhibits the opposite monotonic trend, indicating enhanced distillation capability. These results highlight distinct operational behaviors of physically accessible and inaccessible regions under relativistic effects, providing insight into quantum imaginarity in curved spacetime.
Abstract The black hole information paradox arises from the tension between the thermal spectral properties of Hawking radiation and the unitarity principle in quantum mechanics. To explore the dynamical evolution characteristics of quantum fields in this context, we employ the standard quantization formalism for Dirac fields in Schwarzschild spacetime and investigate the coupling structure of particle and antiparticle modes within a framework that transcends the single-mode approximation. By calculating the states of externally observable subsystems, we systematically derive the evolution of concurrence and first-order coherence as functions of the Hawking temperature. Additionally, we assess the impact of varying initial parameters on these quantities. We further contrast the quantum entanglement differences between the observable exterior region and the black hole interior across diverse temperature regimes. These results provide valuable insights into the evolution of entanglement and coherence in curved spacetime.
Abstract We investigate how the Hawking effect reshapes distinct quantum resources of Dirac fields in Schwarzschild spacetime beyond the single-mode approximation. By quantifying quantum entanglement and coherence using the negativity, the l 1 -norm of coherence and the relative entropy of coherence, we observe a significant asymmetry in their response to gravitational effects. While the Hawking effect monotonically degrades entanglement and drives it toward a finite residual value, quantum coherence is instead monotonically amplified with increasing Hawking temperature, revealing the black hole as an effective decohering environment for nonlocal correlations but a coherence-enhancing mechanism for local superposition. Notably, we further find that under the influence of the Hawking effect, the maximally entangled state does not necessarily correspond to the largest initial negativity. In fact, its value may even be smaller than that of certain non-maximally entangled states. Our results demonstrate that gravity acts in a highly nonuniform manner on different facets of quantumness and highlight the necessity of resource-adapted state engineering for relativistic quantum information processing near the event horizon of the black hole.
Abstract We investigate the behavior of quantum correlations and quantum uncertainty in tripartite systems subjected to Hawking radiation in the background of a Schwarzschild black hole. By considering different bipartitions of accessible and inaccessible field modes separated by the event horizon, we analyze three complementary quantum information measures: the symmetry resolved entanglement entropy (SREE), the quantum speed limit (QSL), and the Wigner Yanase Skew information (SI). Our analysis shows that the QSL decreases monotonically with increasing Hawking temperature, indicating that Hawking radiation enhances the distinguishability of the reduced quantum states along the Hawking radiation trajectory. In contrast, the skew information decreases only for partitions composed solely of accessible modes, reflecting a reduction in local quantum uncertainty caused by thermal mixing. The SREE, however, decreases only when the subsystem includes the inaccessible inside horizon mode of Alice, revealing a suppression of symmetry sector mixing due to the redistribution of entanglement across the horizon. These results demonstrate that Hawking radiation does not simply degrade quantum correlations but instead redistributes them between accessible and inaccessible sectors of the field. The combined analysis of SREE, SI, and QSL therefore provides a unified perspective on how relativistic effects reshape quantum information in curved spacetime.
Abstract In the past two decades, the exploration of quantumness within Schwarzschild spacetime has garnered significant interest, particularly regarding the Hawking radiation’s impact on quantum correlations and quantum coherence. Building on this foundation, we investigate how Hawking radiation influences maximal steered coherence (MSC)-a crucial measure for gauging the ability to generate coherence through steering. We find that as the Hawking temperature increases, the physically accessible MSC degrade while the unaccessible MSC increase. This observation is attributed to a redistribution of the initial quantum correlations, previously acknowledged by inertial observers, across all bipartite modes. In particular, we find that in limit case that the Hawking temperature tends to infinity, the accessible MSC equals to 1/2 1 / 2 of its initial value, and the unaccessible MSC between mode A and B B ¯ also equals to the same value. Our findings illuminate the intricate dynamics of quantum information in the vicinity of black holes, suggesting that Hawking radiation plays a pivotal role in reshaping the landscape of quantum coherence and entanglement in curved spacetime. This study not only advances our theoretical understanding of black hole thermodynamics but also opens new avenues for investigating the interface between quantum mechanics and general relativity.