The emergence of classicality is fundamentally driven by the interaction between a quantum system and its environment. Foundational open-system approaches, notably the Caldeira-Leggett model, successfully captured how these interactions lead to macroscopic effects like quantum dissipation and decoherence. However, these approaches often leave the precise definitions of classicality and quantumness ambiguous. In quantum information theory, this boundary is a heavily scrutinized question, and Kochen-Specker contextuality emerges as a hallmark of nonclassicality. It is therefore natural to investigate whether decoherence can actually suppress this property. Taking this path creates an apparent conundrum, once there exist two distinct manifestations of quantum contextuality: state-dependent and state-independent ones. While state-dependent contextuality naturally vanishes under state degradation, state-independent contextuality could persist for any quantum state, since it shows up even for the maximally mixed state! In this paper, we resolve this apparent paradox by analyzing sequential measurement implementations of the paradigmatic Klyachko, Can, Binicioğlu, and Shumovsky (KCBS) and Peres-Mermin prepare-and-measure scenarios under the influence of depolarizing channels. By introducing depolarizing noise both prior to and in between measurements, and by analyzing the resulting sequential correlators in both the Schrödinger and Heisenberg pictures, we show how open-system dynamics suppress the correlations required to witness contextuality, leading to classicalization.
The ground state decay analysis is carried out for the radioactive ^252 Cf nucleus, as it can decay through multiple disintegration pathways. An attempt is made to understand the same in the present work by employing a theoretical approach based on quantum mechanical fragmentation theory (QMFT). The binary decay is analyzed using the preformed cluster model (PCM), employing two different nuclear interaction potentials: the proximity potential and the Skyrme energy density formalism (SEDF). Our study reveals that the potential based on SEDF (SKT3 force) demonstrates a reasonable agreement with experimental half-lives. Furthermore, the SKT3 force is employed to investigate the ternary fission of the ^252 Cf nucleus. For both cases (binary and ternary) the mass distribution of spherical configuration leads to nearly symmetric fragments, whereas the fragments with higher mass asymmetry start operating for the cold-elongated configuration. In addition to this, the relative yield for ternary fission of the ^252 Cf nucleus is calculated and compared with experimental data.
The observation of multiple antimagnetic rotational (AMR) bands of different parity in a nucleus provides valuable insight into the underlying shears mechanism in weakly deformed or nearly spherical nuclei. Antimagnetic rotation is generally characterized by a varying dynamic moment of inertia ^(2) , a decreasing trend of reduced quadrupole transition probabilities B(E2), with increasing spin, and a corresponding increase in the ratio ^(2) /B(E2). Here, the semiclassical particle-rotor model is employed to investigate the rotational bands of ^102 Ru nucleus, and AMR is obtained in the spin ranging from 15 ħ - 23 ħ for the negative parity Band-2 with configuration π (g_9/2)^-2 ⊗ ν ((h_11/2) (g_7/2)^3) , including a core contribution of 2 ħ . The calculated B(E2) values for ^102 Ru show a decreasing trend with spin and follow the systematics of the neighbouring nuclei ^104 Pd, ^105 Pd, ^106 Cd, and ^107 Cd, a support for AMR character in negative parity band. The present results, when considered together with the previously reported AMR in the positive-parity Band-1, theoretically establish the possibility of the presence of antimagnetic rotations in both positive and negative-parity bands, i.e., multiple AMR in ^102 Ru. This extends the systematics of antimagnetic rotation in the A ≈ 100 mass region and provides a theoretical basis for future lifetime measurements in ^102 Ru.
The generation of terahertz (THz) radiation through the self-focusing of a Gaussian laser beam in an array of vertically aligned quasi-metallic carbon nanotubes (VA-QMCNTs) embedded on a non-conductive glass substrate is investigated. Since ω / ωp > 1, the Gaussian laser beam propagates through the plasma. During propagation, the laser field modifies the plasma refractive index, and the resulting intensity-dependent change in refractive index leads to self-focusing of the beam. As the Gaussian beam traverses the plasma, its transverse intensity gradient exerts a nonlinear ponderomotive force on the electrons within the VA-QMCNTs. This interaction modifies the electron density and induces nonlinear currents, which serve as the source of THz radiation. The output THz power is substantially enhanced in regions where self-focusing is more pronounced. Furthermore, resonant enhancement of THz generation is observed at specific laser parameters, such as normalised pulse duration, beam width parameter, and spot size. The role of electron collision frequency in shaping the THz output is also examined. Numerical analysis reveals that the proposed scheme offers a promising pathway for THz generation. Given the strong sensitivity of THz radiations to tissue water content, the proposed scheme is relevant to non-invasive imaging of superficial tissues, including burn-depth and hydration assessment.
This research aims to identify the optimal target design for generating neutrons using a 6 MeV electron linear accelerator (e-Linac) within the Small Scale - Accelerator Driven System (SS-ADS) experimental facility of 99Mo isotope production. The methodology employs particle transport simulations using the Particle and Heavy Ion code Transport System (PHITS), combined with Response Surface Methodology (RSM) for statistical optimization. With a beam radius of 0.1 cm, the optimal target system for the 6 MeV e-Linac incorporates an iridium pitcher and a beryllium catcher (Ir-Be) configuration. The optimal radius and thickness dimensions of the pitcher are 0.1 cm and 0.21 cm respectively, while the catcher should have a radius and thickness of 1 cm each. This Ir-Be target system configuration design can produce a total neutron flux of 3.85 106 n/cm².s.µA. Since the external neutron source requirement for experimental SS-ADS is on the order of 108 n/cm2.s, the design plan of 6 MeV e-Linac should have an electron current of 0.1 mA.
Dementia is a neurological disorder that causes memory loss and other symptoms. Alzheimer’s disease (AD) and frontotemporal dementia (FTD) are clinically important forms of dementia, yet differentiating them from each other and from cognitively normal (CN) individuals remains a major clinical challenge due to overlapping electrophysiological signatures. Monitoring brain function using electroencephalography (EEG) signals enables real-time assessment of neurophysiological changes associated with dementia. This study presents a deep learning framework that leverages EEG-derived time–frequency (TF) images and convolutional neural networks (CNNs) for robust, non-invasive classification of dementia subtypes. The proposed custom lightweight CNN was trained and evaluated using the public OpenNeuro database, which includes 88 participants. The EEG recordings were preprocessed to remove artifacts and noise, and three TF methods—Continuous Wavelet Transform (CWT), Wavelet Synchrosqueezing Transform (WSST), and Discrete Wavelet Transform (DWT)—were applied to generate spectro-temporal images capturing multiscale neural dynamics. The results show that the proposed lightweight architecture achieves 95.00
The discrepancy between early- and late-time determinations of the Hubble constant, known as the Hubble tension, has motivated a variety of extensions to the standard cosmological model. Among the proposed solutions, Early Dark Energy (EDE) scenarios have received significant attention due to their ability to modify the sound horizon at recombination and potentially alleviate this tension. In this review, we present an overview of EDE models, focusing on their theoretical foundations and phenomenological features. We also provide a dataset-oriented synthesis of EDE constraints, discussing how the inferred viability of EDE depends on the interplay between CMB datasets, local H_0 priors, large-scale structure probes, and parameter-volume effects. Our goal is to provide a unified and pedagogical account of how the theoretical realization of the EDE component and the choice of observational dataset jointly determine the inferred values of H_0 , f_EDE , z_c and S_8 . We further discuss the main challenges faced by these models, including their impact on large-scale structure observables, theoretical consistency issues, and remaining tensions with late-time data. Finally, we highlight prospects for future observational tests aimed at clarifying their role in the Hubble tension.
The stimulated Raman shortcut-to-adiabatic passage (STIRSAP) technique has been demonstrated to accelerate adiabatic population transfer processes. Traditionally applied to three-level atomic systems, this method enables rapid and efficient population transfer in a short interaction time. In this work, we extend this approach to a four-level N -type system driven by three laser fields. Under the three-photon phase matching condition, the first-order Doppler effect can be completely eliminated, making this configuration more suitable for applications in frequency metrology and quantum information processing. By adiabatically eliminating the intermediate state, the four-level system is effectively reduced to a two-level model, enabling the application of counterdiabatic driving without requiring additional couplings. This approach allows for fast and efficient population transfer between metastable states. We analyze the influence of laser intensity peaks and detuning, and we show that the transfer time is significantly shorter than that achieved with the STIRAP technique. Moreover, we also show that an optimal coupling strength between the ground and metastable states further minimizes the operation time.
Magnetic and structural properties of cellulose decorated with magnetite nanoparticles prepared via a co-precipitation method were analyzed. All samples presented magnetisation loops coherent with a superposition of superparamagnetic and ferromagnetic contributions. This feature is attributed to the size distribution of the magnetic nanoparticles and it was observed that weak and demagnetising inter-particle interactions are present. Magnetic parameters like coercivity and remanent magnetisation, however, are mainly governed by the average particle size, and not by such interactions. X-ray diffraction, transmission and scanning electron microscopy were employed for structural investigation, and revealed the presence of magnetite and goethite in some samples.
Accurate prediction of thermodynamic properties such as enthalpy of formation (ΔHf) is essential for designing chemical compounds with targeted stability and performance. In this study, a computational screening of polycyclic aromatic hydrocarbons (PAHs) was conducted using machine learning (ML) models trained on experimentally reported ΔHf values. Over 200 molecular descriptors were calculated via RDKit, with feature selection guided by correlation analysis to retain the most relevant parameters. Twelve ML algorithms were evaluated, with CatBoost and XGBoost demonstrating superior predictive accuracy, achieving R² scores above 0.95 on validation sets. These optimized models were applied to the COMPAS database of 34,000 PAHs to identify candidates with low predicted ΔHf values. Fifty top-ranked compounds were shortlisted based on predicted thermodynamic stability, synthetic accessibility (SA), and chemical similarity network (CSN) analysis. Selected candidates exhibited SA scores between 1.4 and 1.9, suggesting feasible synthesis routes. Visualization via t-SNE and CSN highlighted structural diversity while confirming clustering of low-ΔHf compounds. The approach demonstrates the integration of ML prediction, synthetic feasibility assessment, and chemical space mapping as an efficient strategy for targeted molecular discovery.
We study the dynamics of charged particles in uniaxial lossless and lossy magnetic media. For lossless case, the dispersion surfaces have spherical topology and the trajectories of the particles show no bifurcations. For the case where loss is present, the dispersion surfaces are hyperboloids and for some values of the particles momenta, bifurcations occur. This is shown by deploying the AI Poincaré algorithm to obtain the corresponding explained variance ratios. The behavior of these explained ratios change at bifurcations. We show this for some values of the permeability tensor components and some different choices of the initial conditions.
This study explores a discrete memristive neuron model based on sinusoidal transformation (MBST), filling a gap in chaotic neural network research. By coupling a sinusoidal memristor to a discrete neuron model, the system exhibited improved hyperchaotic dynamics, as confirmed by phase portraits, bifurcation diagrams and Lyapunov spectra. The fixed-point method analyzes stability, whereas linear augmentation effectively controls multi-stability by moving the system to a monostable regime. For synchronization, a master-slave architecture with non-singular sliding-mode control outperforms traditional adaptive methods, ensuring robust coordination between neurons. Hardware validation using an ATmega 2560 microcontroller demonstrated real-time feasibility, with results matching those of numerical simulations. A TFT screen (320x480 pixels) was used to visualize the hyperchaotic dynamics, thereby confirming its practical implementation. The complex and controllable behavior of this model offers perspectives for chaos-based encryption, leveraging its unpredictability and synchronization properties.
The proton -radiative capture reaction 6Li (p, γ)7Be is of outstanding importance in nuclear physics and astrophysics, in particular in understanding key processes of nucleosynthesis on cosmic scales. This reaction plays a decisive role not only in the early stages of Big Bang Nucleosynthesis (BBN), where the production of light elements is modeled in the first minutes after the Big Bang, but also in stellar fusion chains, in particular in the side branches of the proton-proton chain (pp-chain) in Sun-like stars. In addition, 6Li(p,γ)7Be acts as one of the channels for the loss of 6Li in relatively low-temperature stellar environments and is therefore also of importance in the study of the relative abundances of light elements in the Universe and the chemical evolution of galaxies. At very low energies relevant to astrophysical environments (especially in the range of a few keV), the nuclear cross section is strongly influenced by a range of non-nuclear influences, suppressed by the Coulomb potential and significant quantum mechanical effects. To normalize these effects and extract the intrinsic nuclear behavior, the astrophysical S-factor is used, which describes the behavior of the cross section in a regular manner in the low-energy limit, where the probability of Coulomb penetration is low. In the case of the 6Li (p, γ) 7Be reaction, the S-factor at sub-Coulomb energies is mainly controlled by electric dipole (E1) transitions from the S-wave input state (in the p + 6Li system) to the ground states of 7Be with 2P1/2 and 2P3/2.
Organic photodiodes based on donor–π–acceptor (D–π–A) molecular architectures have attracted significant attention owing to their tunable optoelectronic properties, solution-processability, and potential for low-cost photodetection applications. However, despite the remarkable photophysical characteristics of dibenzosuberenone derivatives, studies investigating anthracene-functionalized dibenzosuberenone-based D–π–A–π–D systems for photodiode applications remain very limited in the literature. In this study, a novel π-conjugated organic semiconductor (BADA) possessing a D–π–A–π–D architecture was rationally designed and synthesized starting from dibenzosuberone through multistep aromatic functionalization and Sonogashira coupling reactions. The resulting molecule consists of anthracenyl donor units, linear ethynyl π-bridges, and a dibenzosuberenone acceptor core, providing an extended delocalized electronic framework. Subsequently, an Au/BADA/p-Si/Al Schottky-type photodiode was fabricated by spin-coating the BADA interfacial layer onto p-type silicon followed by thermal evaporation of Au and Al contacts. The electrical and photoresponse characteristics of the fabricated device were systematically investigated under illumination intensities ranging from 20 to 100 mW/cm². The ideality factor (n) increased from 1.74 in the dark to 3.96 under illumination, while the barrier height (Φb) decreased from 0.76 eV to 0.57 eV, indicating illumination-induced barrier modulation effects. The photocurrent exhibited a power-law dependence on light intensity with an exponent of m = 1.10, revealing nearly linear and slightly super-linear behavior. The responsivity (R) was found to vary between 1.46 × 10⁻6 and 1.60 × 10⁻6A/W, while the specific detectivity (D*) ranged from 7.9 × 10⁷ to 9.3 × 10⁷ Jones within the investigated illumination range. The photosensitivity increased monotonically, reaching approximately 15 at 100 mW/cm². The obtained results demonstrate that the Au/BADA/p-Si/Al structure exhibits stable and reproducible photoresponse characteristics and represents a promising candidate for organic photodetector applications.
In this paper, we discuss how the principle of Galilean invariance, when applied to the conservation principle of total mechanical energy, imposes certain conditions on the choice of the particle system considered. First, changes in kinetic energy are not, generally, Galilean invariant, and second, potential energy must be defined for an interaction. We extend the definition of potential energy for interacting particles and show that total potential energy cannot be defined, in an invariant way, for arbitrary particle systems. These problems can only be solved if we consider closed systems. We also show how this approach is appropriate for applications of the work-energy theorem and the principle of energy conservation to continuous systems.
We revisit the TFD formulation for finite-temperature field theory and demonstrate its fundamental role in grasping key aspects of real-time finite-temperature field theory. Specifically, we demonstrate that the general unitary SU(1,1) formulation of TFD, in which the conjugation rules are redefined, is consistent with the GNS construction and Tomita-Takesaki theory. We calculate the SU(1,1) thermal propagator and show that the KMS condition is independent of the choice of the SU(1,1) parameters.
In this work, we confirmed the presence of Carbon Quantum Dots (CQDs) by optical techniques such as UV-visible and photoluminescence (PL), after filtering the result of carbonization and sulfonation of microcrystalline cellulose (MCC), which are synthesis processes for obtaining these nanomaterials. The high-resolution transmission electron microscopy (HR-TEM) confirmed, not only the size of the particles, but the crystalline pattern of the carbon-based nanoparticles. The HR-TEM also indicates the presence of Graphene Quantum Dots (GQDs), as anisotropic-shaped particles were observed. Fluorescence and absorbance indicate the pH dependence on optical and structural properties, as well as on the production of CQDs and GQDs. The pH may influence the syntheses of CQDs and GQDs and the origin of their fluorescence, due to presence of functional groups such as hydroxyl, carboxyl, carbonyl, epoxy, and sulfoxide at low pH, and in the edge regions of these particles, with sp² hybridization. The Fourier Transform Infrared (FTIR) spectra was also measured, allowing to understand the functional groups present in the samples, and so, understand the groups responsible for the fluorescence.
The effects of transition metal substitution on the structural, electronic, magnetic, mechanical, and lattice dynamical properties of CePd2In4 and CePt2In4 intermetallic compounds were systematically investigated using first-principles calculations within the generalized gradient approximation. This work constitutes the first comprehensive theoretical study of these materials. The calculated lattice parameters are in agreement with available experimental data. The mechanical stability of both compounds is confirmed as their second-order elastic constants satisfy the Born stability criteria. Furthermore, phonon dispersion calculations reveal no imaginary frequencies throughout the Brillouin zone, confirming the dynamical stability of both compounds. Analysis of the mechanical properties revealed significant elastic anisotropy. Electronic structure calculations indicate metallic behaviour arising from the overlap between valence and conduction bands. The combination of high average atomic mass and relatively weak bond strength leads to low Debye temperatures and low thermal conductivity. The estimated melting temperatures are relatively high for both compounds, indicating their suitability for high-temperature applications. These findings suggest that CePd2In4 and CePt2In4 compounds may be promising candidates for high-temperature and thermal control applications.
We propose an experimental scheme that realizes several Boolean operations nonlocally and simultaneously by exploiting the transverse spatial degrees of freedom (TSDF) of photon pairs generated via spontaneous parametric down-conversion (SPDC). Binary information is encoded as matrices in the TSDF using Digital Micromirror Devices (DMDs) placed in the signal and idler beams. The coincidence counting rate for corresponding matrix elements yields the results of six different Boolean operations. We illustrate a possible implementation, discussing its energy costs and finding its capability to process 25 operations in parallel with only a few hundred photons.
