Searcharxiv⌕ Search

arXiv subjects

Mostafa Mansour

Publications and source records attributed to Mostafa Mansour.

At least 19 recordsLinked to original sources
arXiv2026

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

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 $\Delta$, 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 $\Delta$ preferentially enhances collective coherence by strengthening gravitationally induced inter-particle correlations.

quant-ph↗
arXiv2026

Quantum Steering and Nonlocal Correlations Between Non-Interacting Delocalized Electrons Under Rashba Spin-Orbit Interaction

We investigate quantum steering and nonlocal correlations between two electrons in a two-dimensional electron gas (2DEG) as functions of Rashba spin-orbit interaction (RSOI) strength and inter-electron separation. We focus particularly on the Bi/Ag(111) system characterized by its strong RSOI ($\alpha_0 = 3.05\times10^{-11}$ eV~m), and we explore the influence of tuning intensity of RSOI and inter-electron distance on the dynamics of Bell nonlocality, uncertainty-induced nonlocality and steering. We find that, although increasing $\alpha_R$ initially suppresses quantum correlations, all three metrics exhibit a non-monotonic recovery as functions of $\alpha_R$, peaking near an optimal coupling strength $\alpha_R = 4.32\times10^{-11}$~eV~m across the range of inter-electron separations considered. This finding establishes RSOI as a critical control parameter for stabilizing quantum properties in two-dimensional electron gases against the decay of quantum correlations with inter-electron separation, and shows that the suppression and recovery of quantum resources within the Bi/Ag(111) system can be controlled by adjusting the inter-electron distance and carefully tuning the RSOI strength.

quant-ph↗
arXiv2026

Basis-independent coherence and quantum correlations in two dipole-dipole-coupled electrons in double quantum-dot molecules

This work examines the thermal dynamics of basis-independent quantum coherence and correlation-based quantum resources for two dipole-dipole-coupled electrons confined in spatially separated quantum-dot (QD) molecules. Single-dot quantum superpositions and inter-subsystem coherence are characterized by using localized and collective coherence. Quantum correlations between the two double quantum dots are quantified by employing Bures distance entanglement, Local quantum uncertainty (LQU), and local quantum Fisher Information (LQFI). The findings show that dipole-dipole coupling $K$ is the most effective protective parameter, extending the entanglement sudden death temperature, diminishing the local quantum superpositions and enhancing the collective coherence. The dipole-dipole interaction has also a crucial impact on protecting LQU and LQFI beyond the entanglement sudden death temperature. Coulomb repulsion $J$ reinforces this protection through an independent channel, projecting the thermal state onto the entangled $\{|0_A 1_B\rangle,|1_A 0_B\rangle\}$ subspace; their combined action is required to approach the entanglement maximum, and it enhances collective coherence and extends the temperature range over which LQU and LQFI remain appreciable. Energy detuning $\varepsilon$ can enhance localized coherence but paradoxically accelerates the entanglement sudden death and quenches LQU and LQFI by weakening two-body correlations. Inter-dot tunneling $\Gamma$ enhances local superpositions at low temperature, but it reduces collective coherence, lowers the entanglement sudden death temperature, and disrupts other nonclassical correlations.

quant-ph↗
arXiv2026

Time-Fractional Schr\"odinger Evolution in Coupled Double Quantum Dots: Memory Effects on Quantum Resources

Our work explore the time evolution of entanglement, local quantum uncertainty, and correlated coherence, within a system modeled by two double quantum dots. The dynamics is represented using a time-fractional Schr\"odinger equation, which includes memory effects in a non-Markovian regime. We vary the fractional parameter $\tau$, the tunneling amplitudes $\delta_A$ and $\delta_B$, as well as the inter-dot interaction strength $\mathcal{V}$, to investigate how these key parameters govern the generation, stabilization, and decay of quantum resources within the system. The obtained results reveal that, for both initial states, fractional dynamics with a low $\tau$ rapidly generates entanglement expecting maximal values $\mathcal{LN}\approx 1$ and non-classical correlations quantified by local quantum uncertainty. Conversely, higher values of $\tau$ lead to slower entanglement but memory effects allow quantum resources to remain significant for a longer time, with the negativity remaining above ($\approx 0.6$). We also find that higher interaction frequencies $\mathcal{V}$ accelerate correlations and stabilize coherence, while a strong tunneling asymmetry degrades entanglement and coherence despite the initial benefits of increasing quantum resources.

hep-th↗
arXiv2025

Basis-independent coherence and its distribution in de Sitter spacetime

Quantum coherence in curved spacetime offers a fresh window into the interplay between gravity, thermality, and quantum resources. While previous work has shown that Markovian evolution can generate entanglement and other nonclassical correlations in de Sitter backgrounds, the basis-dependent nature of coherence has so far limited its unambiguous interpretation. Here, we introduce a basis-independent framework to quantify not only the total coherence of two comoving detectors, but also its collective and localized contributions, and we trace how each of these decomposed measures varies with the inverse of Gibbons-Hawking temperature. By treating the detectors as open quantum systems interacting with a massless scalar field in the Bunch-Davies and squeezed alpha-vacua, we find that non-thermal squeezing substantially enhances extractable coherence, even under strong thermal effects. Our results demonstrate how basis-independent coherence in de Sitter spacetime can serve as a robust resource for relativistic quantum information protocols.

gr-qc↗
arXiv2025

Dimeric perylene-bisimide organic molecules: Application as a quantum battery

This work introduces a unified theoretical framework for quantum batteries (QBs) constructed from thermally equilibrated arrays of dimeric perylene bisimide (PBI) molecules. These organic dimers, with chemically tunable transition energies and dipole-dipole interactions, constitute a scalable and practical platform for quantum energy storage. Using exact diagonalization of the Gibbs state supported by analytic and numerical resource-theoretic tools, we evaluate four performance metrics: ergotropy, instantaneous charging power, storage capacity, and quantum coherence. We find that exact resonance ($\nu_1 = \nu_2$) suppresses both ergotropy and charging power due to symmetric thermal population distributions. Introducing finite detuning ($\Delta = \nu_1 - \nu_2$) breaks this symmetry, redistributes populations, and significantly enhances extractable work, charging power, and storage capacity. Furthermore, while the capacity remains invariant under unitary dynamics, providing a useful reference bound, intermediate dipole-dipole coupling strengths ($V_{12}$) optimize the trade-off between ergotropy, coherence retention, and storage performance. Crucially, coherence-assisted energy storage persists up to experimentally relevant temperatures, underscoring the thermal resilience of PBI-based QBs. These results establish spectral detuning and dipole-dipole interaction tuning as essential design principles, positioning PBI dimers as a chemically realistic, experimentally accessible, and thermodynamically robust platform that bridges molecular engineering with quantum energy storage.

quant-ph↗
arXiv2025

Stabilization of quantum properties under intrinsic decoherence in presence of external magnetic fields

The dynamical behavior of quantum state properties under intrinsic decoherence models can be modified by the presence of external magnetic fields. Although generically external magnetic fields are detrimental to preserve quantumness in the presence of intrinsic decoherence, judicious adjustment of the magnetic field can stabilize such features. This stabilization arises from novel resonances between energy eigenstates resulting from the presence of an external magnetic field. Here, we present our findings using as a model system two spin 1-particles confined in a double-well potential under intrinsic decoherence. We stress, however, that our results are generic and independent on the used model.

quant-ph↗
arXiv2024

Quantum correlations and metrological advantage among Unruh-DeWitt detectors in de Sitter spacetime

A long-standing debate on Gibbons-Hawking (GH) decoherence centers on its unclear thermal nature. In this work, we investigate the robustness of quantum Fisher information (QFI) and local quantum uncertainty (LQU) in the presence of GH decoherence, using free-falling Unruh-DeWitt (UDW) detectors in de Sitter spacetime (dS-ST). The UDW detectors interact with a massless scalar field in dS-ST and are modeled as open quantum systems, with the field acting as the environment for which we use a master equation to describe their evolution. Our analysis investigates the roles of energy spacing, GH temperature, initial state preparation, and various de Sitter-invariant vacuum sectors on the optimization of QFI and LQU. We find that the optimal values of QFI and LQU depend on the selected de Sitter-invariant vacuum sector and increase with larger energy spacing. Our findings reveal that QFI exhibits resilience to GH decoherence, maintaining a pronounced local peak across a wider range of parameters. This robustness can be further enhanced through strategic initial state preparation and increased energy spacing, resulting in a higher maximum QFI value even under significant environmental decoherence. Our results underscore the critical role of GH thermality in governing QFI and LQU, offering valuable insights for advances in relativistic quantum metrology (RQM).

quant-ph↗
arXiv2024

Performance of a Superconducting Quantum Battery

Finding a quantum battery model that demonstrates a quantum advantage while remaining feasible for experimental production is a considerable challenge. Here, a superconducting quantum battery (SQB) model that exhibits such an advantage is introduced. The model consists of two coupled superconducting qubits that interact during the unitary charging process while remaining in equilibrium with a thermal reservoir. First, the model is described, evidence of the quantum advantage is provided, and then the fabrication process of the battery is discussed using superconducting qubits. Analytical expressions for the ergotropy, instantaneous power, and capacity of the SQB, as well as their connection to quantum coherence are derived. It is demonstrated that leveraging the collective effects of Josephson energies and the coupling energy between qubits allows for optimization, resulting in improved energy redistribution and a significant enhancement in charging efficiency. This work highlights the complexities of tuning system parameters, which increase the potential for work extraction from the SQB, providing a deeper understanding of the charging mechanisms involved. These findings can be applied to superconducting quantum circuit battery architectures, underscoring the feasibility of efficient energy storage in these systems. These results pave the way for proposals of new superconducting devices, emphasizing their potential for efficient energy storage.

quant-ph↗
arXiv2024

Magnetic Dipolar Quantum Battery with Spin-Orbit Coupling

We investigate a magnetic dipolar system influenced by the $z$-component of Zeeman splitting, Dzyaloshinsky--Moriya (DM) interaction, and Kaplan--Shekhtman--Entin-Wohlman--Aharony (KSEA) exchange interaction, with emphasis on the role of quantum resources in both closed and open settings. By analyzing the Gibbs thermal state and solving the Lindblad master equation, we study the behavior of quantum coherence, discord, and entanglement under thermal equilibrium and dephasing noise. After exploring these resources, we apply the model to a closed quantum battery (QB). Our results show that while Zeeman splitting degrades quantum resources in noisy and thermal regimes, it enhances QB performance by improving ergotropy, anti-ergotropy, storage capacity, and coherence during cyclic charging. The axial parameter further amplifies performance, leading to coherence saturation and persistent ergotropy growth, in line with the notion of incoherent ergotropy. KSEA interaction and the rhombic term consistently preserve coherence and entanglement under noise, thereby strengthening QB functionality. DM interaction mitigates thermal degradation of resources in the Gibbs state and improves performance, though its effect is limited under Pauli-$X$ dephasing. We reveal diverse behaviors, including increased ergotropy without coherence and the coexistence of coherence with zero extractable work. Finally, we propose Nuclear Magnetic Resonance (NMR) as a feasible platform for experimental implementation.

quant-ph↗
arXiv2024

UDGS-SLAM : UniDepth Assisted Gaussian Splatting for Monocular SLAM

Recent advancements in monocular neural depth estimation, particularly those achieved by the UniDepth network, have prompted the investigation of integrating UniDepth within a Gaussian splatting framework for monocular SLAM. This study presents UDGS-SLAM, a novel approach that eliminates the necessity of RGB-D sensors for depth estimation within Gaussian splatting framework. UDGS-SLAM employs statistical filtering to ensure local consistency of the estimated depth and jointly optimizes camera trajectory and Gaussian scene representation parameters. The proposed method achieves high-fidelity rendered images and low ATERMSE of the camera trajectory. The performance of UDGS-SLAM is rigorously evaluated using the TUM RGB-D dataset and benchmarked against several baseline methods, demonstrating superior performance across various scenarios. Additionally, an ablation study is conducted to validate design choices and investigate the impact of different network backbone encoders on system performance.

cs.CV↗
arXiv2024

Quantum obesity and steering ellipsoids for fermionic fields in dilaton black hole

This paper investigates quantum obesity (QO), quantum discord (QD), and the quantum steering ellipsoid (QSE) for bipartite Gisin states subjected to Garfinkle-Horowitz-Strominger (GHS) dilation of spacetime on the second qubit. These three quantifiers are introduced to characterize quantum correlations beyond entanglement and can also function as entanglement witnesses. Our results demonstrate a monotonic decrease in the physical accessibility of both QD and QO as the dilation parameter increases within the region-I of the second qubit. Conversely, in the anti-particle region, the accessibility of QD and QO stabilizes at finite values of the dilation parameter owing to the influence of the Pauli exclusion principle and Fermi-Dirac statistics, subsequently increasing gradually. Notably, the QSE in the region-I expands as the Dirac field frequency rises and the dilation parameter diminishes, while the opposite trend is observed in the anti-particle region.

quant-ph↗
arXiv2024

Physically Accessible and Inaccessible Quantum Correlations of Dirac Fields in Schwarzschild Spacetime

In this study, we investigate the influence of Hawking decoherence on the quantum correlations of Dirac fields between \textit{Alice} and \textit{Bob}. Initially, they share a \textit{Gisin} state near the Schwarzschild black hole (SBH) in an asymptotically flat region. Then, \textit{Alice} remains stationary in this region, while \textit{Bob} hovers near the event horizon (EH) of the SBH. We expect that \textit{Bob}, using his excited detector, will detect a thermal Fermi-Dirac particle distribution. We assess the quantum correlations in the evolved \textit{Gisin} state using quantum consonance and uncertainty-induced non-locality across physically accessible, physically inaccessible, and spacetime regions. Our investigation examines how these measures vary with Hawking temperature, Dirac particle frequency, and the parameters of the initial \textit{Gisin} state. Additionally, we analyze the distribution of these quantum correlation measures across all possible regions, noting a redistribution towards the physically inaccessible region. Our findings demonstrate that Hawking decoherence reduces the quantum correlations of Dirac fields in the physically accessible region, with the extent of reduction depending on the initial state parameters. Moreover, as Hawking decoherence intensifies in the physically inaccessible and spacetime regions, the quantum correlations of Dirac fields reemerge and ultimately converge to specific values at infinite Hawking temperature. These results contribute to our understanding of quantum correlation dynamics within the framework of relativistic quantum information (RQI).

quant-ph↗
arXiv2024

Distribution of distance-based quantum resources outside a radiating Schwarzschild black hole

We obtain analytical expressions for distance-based quantum resources and examine their distribution in the proximity of a Schwarzschild black hole (SBH) within a curved background. For an observer in free fall and their stationary counterpart sharing the Gisin state, the quantum resources are degraded at an infinite Hawking temperature. The extent of this degradation that occurs as the SBH evaporates is contingent upon the fermionic frequency mode, Gisin state parameters, and the distance between the observer and the event horizon (EH). In the case of two accelerating detectors in Minkowski spacetime interacting with quantum fluctuating scalar fields (QFSF), we find that quantum coherence and discord exhibit sudden disappearance for certain initial states and sudden reappearance for others except entanglement, regardless of the Unruh temperature. We also discover that the quantum resources of one detector can be transferred to another in the case of two stationary detectors through a fluctuating quantum field outside the SBH. We demonstrate that, in contrast to coherence and discord, we are unable to regenerate entanglement for a given initial state and that they are equal for different vacuum states. In certain circumstances, the presence of EHs does not significantly reduce the available resources, as it turns out that all interesting phenomena occur within EHs. Since the world is basically non-inertial, it is necessary to understand the distribution of quantum resources within a relativistic framework.

quant-ph↗
arXiv2022

Effect of induced transition on the quantum entanglement and coherence in two-coupled double quantum dots system

Studying quantum properties in solid-state systems is a significant avenue for research. In this scenario, double quantum dots (DQDs) appear as a versatile platform for technological breakthroughs in quantum computation and nanotechnology. This work inspects the thermal entanglement and quantum coherence in two-coupled DODs, where the system is exposed to an external stimulus that induces an electronic transition within each subsystem. The results show that the introduction of external stimulus induces a quantum level crossing that relies upon the Coulomb potential changing the degree of quantum entanglement and coherence of the system. Thus, the quantum properties of the system can be tuned by changing the transition frequency, leading to the enhancement of its quantum properties.

quant-ph↗
arXiv2022

Intrinsic decoherence effects on correlated coherence and quantum discord in XXZ Heisenberg model

Spin qubits are at the heart of technological advances in quantum processors and offer an excellent framework for quantum information processing. This work characterizes the time evolution of coherence and nonclassical correlations in a two-spin XXZ Heisenberg model, from which a two-qubit system is realized. We study the effects of intrinsic decoherence on coherence (correlated coherence) and nonclassical correlations (quantum discord), taking into consideration the combined impact of an external magnetic field, Dzyaloshinsky-Moriya (DM) and Kaplan Shekhtman Entin-Wohlman-Aharony (KSEA) interactions. To fully understand the effects of intrinsic decoherence, we suppose that the system can be prepared in one of the two well-known extended Werner-like (EWL) states. The findings show that intrinsic decoherence leads the coherence and quantum correlations to decay and that the behavior of the aforementioned quantum resources relies strongly on the initial EWL state parameters. We, likewise, found that the two-spin correlated coherence and quantum discord; become more robust against intrinsic decoherence depending on the type of the initial state. These outcomes shed light on how a quantum system should be engineered to achieve quantum advantages.

quant-ph↗
arXiv2019

Indoor Navigation Using Information From A Map And A Rangefinder

The problem of indoor navigation of mobile objects, using a map and measurements of distances to the walls is considered. A nonlinear filtering problem aimed at calculating the optimal, in the root-mean-square sense, of the sought parameters is formulated in the context of the Bayesian approach. The algorithm for its solution based on the point-mass method is described. The simulation results illustrating the advantages of the proposed problem statement and the resultant algorithm are discussed.

cs.RO↗