Abstract We studied the dynamics of a pair of single-electron double quantum dots (DQD) under longitudinal and transverse static magnetic fields and time-dependent harmonic modulation of their interaction couplings. We propose to modulate the tunnel coupling between the QDs to produce one-qubit gates and the exchange coupling between DQDs to generate entangling gates, the set of operations required for quantum computing. We developed analytical approximations to set the conditions to control the qubits and applied them to numerical calculations to test the accuracy and robustness of the analytical model. The results shows that the unitary evolution of
the two-electron state performs the designed operations even under conditions shifted from the ideal ones.

ABSTRACT This paper presents a comprehensive numerical analysis of magnetohydrodynamic (MHD) Casson nanofluid movement over a permeable, linearly stretching sheet, integrating the contributions of non‐uniform heat generation or absorption and chemical interaction. The mathematical model integrates the non‐Newtonian attribute of Casson fluids and enhanced thermal conductivity due to nanoparticles. A uniform transverse magnetic field is imposed, and wall permeability is considered to simulate suction or injection. Through similarity variables, the primary nonlinear partial differential equations are reduced to a system of ordinary differential equations, which are then solved numerically. The influences of various physical parameters including the Casson fluid parameter, magnetic field strength, heat source/sink coefficient, and chemical reaction rate on velocity, microrotation, temperature, and concentration profiles are thoroughly investigated. The study reveals that magnetic damping, viscous resistance, and stretching elevate Casson nanofluid motion and thermal transport, with Brownian motion intensifying internal energy and thermal boundary thickness. Increasing chemical consumption actively removes flow species. Using response surface methodology (RSM), model accuracy and significance are assessed through analysis of variance (ANOVA) for different parameters. Using RSM and ANOVA, model accuracy is validated through regression metrics.

Ruthenium dioxide (RuO2) has recently emerged as an altermagnetic candidate, but its intrinsic magnetic ground state in thin films remains widely debated. This study aims to clarify the nature and spatial extent of the magnetic order in RuO2 thin films grown under different conditions. Thin films of RuO2 with thicknesses of 30 and 33 nm are deposited by pulsed laser deposition and sputtering onto TiO2(110) and Al2O3(1¯102) substrates, respectively. Low-energy muon spin rotation/relaxation (LE-μSR) with depth-resolved sensitivity measurements is performed in transverse magnetic fields (TF) from 4 K to 290 K. The μSR data collected with a muon implantation energy of 1 keV reveal that magnetic signals originate from the near-surface region of the film (≲10 nm), and the affected volume fraction is approximately 8.5%. The localized magnetic response is consistent across different substrates, growth techniques, and parameter sets, suggesting a common origin related to surface defects and dimensionality effects. The combined use of TF-μSR and the study of depth-dependent implantation with low-energy muons provides direct evidence for surface-confined, inhomogeneous static magnetic order in RuO2 thin films, helping reconcile discrepancies. These findings underscore the importance of considering reduced-dimensional contributions and motivate further investigation into the role of defects, strain, and stoichiometry on the magnetic properties of RuO2, especially at the surface.

Abstract We investigated JUNO’s sensitivity to a possible conversion of solar neutrinos into antineutrinos via the spin-flavor precession mechanism, and assessed the implications for constraining the neutrino-magnetic moment. Using a sensitivity-based framework appropriate for counting experiments with no prior observations, we derive 90% confidence level ensemble-average sensitivities on the solar antineutrino flux for 1.8–16.8 and 8.0–16.8 MeV. For the entire energy window, the results do not improve the restrictions of other experiments; the relevance occurs in the highest-energy window. In this window, we report a flux of ϕ lim ≤ 4.01 × 1 0 1 cm − 2 s − 1 and a probability of P ν e → ν ¯ e ≤ 2.07 × 1 0 − 5 , the latter normalized to the 8 B flux above threshold, Φ SSM ( E > 8 MeV). Assuming transverse solar magnetic fields of B ⊥ = 50 and 100 kG, the corresponding magnetic-moment sensitivities are μ ν ≤ 7.27 × 10 −11 μ B and 3.64 × 10 −11 μ B in the high-energy window. These results highlight that JUNO has the potential to achieve sensitivities comparable to the most stringent astrophysical limits; in particular, the high-energy selection (8.0–16.8 MeV) provides a sensitivity that is competitive with current results, while the full-energy window remains primarily limited by near-reactor backgrounds.

This study examines the effect of Navier slip on entropy generation in magnetohydrodynamic (MHD) hybrid nanofluid flow through a parallel channel. The analysis considers entropy contributions from heat transfer, fluid friction, and magnetic field interactions. Using the method of lines, velocity, temperature, and entropy generation profiles are computed and analysed. The results reveal that introducing slip at the channel walls significantly reduces total entropy generation, primarily by lowering viscous dissipation in the boundary layers. The hybrid nanofluid, composed of multiple nanoparticles, enhances thermal transport and further decreases thermal irreversibility compared to conventional nanofluids. However, the application of a transverse magnetic field leads to a marked increase in entropy production due to the opposing Lorentz forces, with the effect becoming more pronounced at higher magnetic field intensities. The interplay between slip and magnetic effects creates a trade-off, where moderate slip lengths and optimised nanoparticle composition yield the most thermodynamically efficient flow regime. These insights guide the improvement of the performance of MHD-based thermal systems in applications such as electronic cooling and energy conversion technologies.

Abstract In this research, we conduct a comprehensive analysis of the steady, two-dimensional laminar flow of a non-Newtonian Williamson nanofluid confined between two inclined and fixed parallel plates, subjected to a uniform transverse magnetic field. The nanofluid dynamics are modeled using the Wakif-Buongiorno’s model, which effectively incorporates essential nanoparticle transport mechanisms such as Brownian motion and thermophoresis. By employing appropriate dimensionless variables, the governing equations are systematically transformed into their dimensionless forme, facilitating analytical and numerical treatment. The main contributions of this study lie in the theoretically well-detailed mathematical formulation of the problem. To solve the resulting system of nonlinear ordinary differential equations, we utilize the semi-analytical, the Homotopy Perturbation Method (HPM), and we critically examine its applicability and limitations within the context of our problem. Furthermore, we apply the midpoint Richardson extrapolation technique implemented via the Midrich function in MAPLE software to enhance the accuracy of our solutions. The influence of various dimensionless parameters on the temperature and concentration profiles is systematically investigated, and the findings yield important insights with practical implications for engineering applications, especially in fields where magnetohydrodynamic nanofluid flows are of industrial relevance.

In most lattice models, gap closing typically occurs at high-symmetry points in the Brillouin zone. In the transverse field Ising model with cluster interaction, the gap closes at high-symmetry points, as well as at the phase transition between paramagnetic and cluster phases, where the gap-closing mode can be moved by tuning the strength of the cluster interaction. We take advantage of this property to examine the nonequilibrium dynamics of the model in the framework of dynamical quantum phase transitions (DQPTs) after a noiseless and noisy ramp of the transverse magnetic field. The numerical results show that DQPTs always happen if the starting or ending point of the quench field is restricted between two critical points. In other ways, there is always critical sweep velocity above which DQPTs disappear. Our finding reveals that noise modifies drastically the dynamical phase diagram of the model. We find that the critical sweep velocity decreases by enhancing the noise intensity and scales linearly with the square of noise intensity for weak and strong noise. Moreover, the region with multi-critical modes (MCMs) induced in the dynamical phase diagram by noise. The sweep velocity under which the system enters the MCMs region increases by enhancing the noise and scales linearly with the square of noise intensity.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-26732-4.

The superconducting diode effect (SDE) is characterized by the nonreciprocity of Cooper-pair motion with respect to current direction. In three-dimensional (3D) materials, SDE results in a critical current that varies with direction, making the effect distinctly observable: the material exhibits superconductivity in one direction while behaving as a resistive metal in the opposite direction. However, in genuinely two-dimensional (2D) materials, the critical current density is theoretically zero, leaving the manifestation of SDE in the 2D limit an intriguing challenge. Here, we present the observation of SDE in a heterostructure composed of the topological insulator Bi_{2}Te_{3} and the iron-based superconductor Fe(Se,Te)-a candidate for topological superconductor-where superconductivity is confined to the 2D limit. The observed I-V characteristics reveal nonreciprocity in the vortex-creep regime, where finite voltages arise due to the 2D nature of superconductivity. Furthermore, our 2D film demonstrates abrupt voltage jumps, influenced by both the current flow direction and the transverse magnetic field direction. This behavior resembles that of 3D materials but, in this case, is driven by the vortex-flow instability, as illustrated by voltage-controlled S-shaped I-V curves. These results underscore the pivotal role of vortex dynamics in SDE and provide new insights into the interplay between symmetry breaking and two dimensionality in topological insulator/superconductor systems.

Abstract Prominence seismology, applied to large-amplitude longitudinal oscillations, is used to indirectly diagnose the geometry and strength of the magnetic fields inside the prominence. In this paper, combining imaging and spectroscopic data, the magnetic field configuration of a quiescent prominence is revealed by large-amplitude longitudinal oscillations observed in end view on 2023 December 4. In particular, the prominence oscillation involved blueshift velocities in Dopplergrams and horizontal motions in extreme-ultraviolet images. Originally, the prominence oscillation was triggered by the collision and heating of an adjoining hot structure associated with two coronal jets. The oscillation involved two groups of signals with similar oscillatory parameters, a three-dimensional (3D) initial amplitude of ∼40 Mm and a 3D velocity amplitude of ∼48 km s −1 , both lasting for ∼4 cycles with a period of ∼77 minutes, with a phase difference of ∼ π /8. The angle between the 3D velocities and the prominence axis ranges from 10 ∘ to 30 ∘ . Two methods, utilizing time–distance diagrams and velocity fields, are employed to calculate the curvature radius of magnetic dips supporting the prominence materials. Both methods yield similar value ranges and trends from the bottom to the top of magnetic dips, with the curvature radius increasing from ∼90 Mm to ∼220 Mm, then decreasing to ∼10 Mm, with transverse magnetic field strength ≥25 Gauss. From this, the realistic 3D geometry of the prominence magnetic dips is determined to be sinusoidal. To the best of our knowledge, we present the first accurate calculation of the 3D curvature radius and geometry of the prominence magnetic dips based on longitudinal oscillatory motions.

In this paper, we prove the linear and nonlinear ill-posedness of the well-known Kelvin–Helmholtz problem of the incompressible ideal magnetohydrodynamics (MHD) equations with transverse magnetic field. Our analysis rigorously verifies that “the development of the Kelvin–Helmholtz instability, in the direction of the streaming, is uninfluenced by the presence of the magnetic field in the transverse direction” which was proposed by Chandrasekhar [Hydrodynamic and Hydromagnetic stability (Oxford University Press, New York, 1961)].

Abstract The dynamical properties of the Lipkin–Meshkov–Glick model with longitudinal and transverse fields are studied by considering quantum quenches. The model describes a many-body quantum system with long-range interactions. A semiclassical analysis is performed to obtain the critical points of quantum phase transitions. These critical points consist in the static separatrix, which is found by analyzing the stability structure of the semiclassical potential and is useful in the identification of ground state and excited states quantum phase transitions, and in the dynamical separatrix, which depends on initial conditions and is found by studying the classical equations of motion for the Hamiltonian. The static and dynamical separatrices divide the parameter space in regions of different dynamical behavior, and it is found that both separatrices play an important role in the determination of the occurrences of the dynamical quantum phase transitions. Graphical abstract

Improving the high-frequency performance of FeSiAl/MoS2 composites with small particle size and transverse magnetic field

Thermal Phase Transitions in a Deformable Quantum Spin-1/2 XX Chain in a Transverse Magnetic Field

Abstract We propose and evaluate a quantum-inspired algorithm for solving Quadratic Unconstrained Binary Optimization (QUBO) problems, which are mathematically equivalent to finding ground states of Ising spin-glass Hamiltonians. The algorithm employs Matrix Product States (MPS) to compactly represent large superpositions of spin configurations and utilizes a discrete driving schedule to guide the MPS toward the ground state. At each step, a driver Hamiltonian—incorporating a transverse magnetic field—is combined with the problem Hamiltonian to enable spin flips and facilitate quantum tunneling. The MPS is updated using the standard Density Matrix Renormalization Group (DMRG) method, which iteratively minimizes the system’s energy via multiple sweeps across the spin chain. Despite its heuristic nature, the algorithm reliably identifies global minima, not merely near-optimal solutions, across diverse QUBO instances. We first demonstrate its effectiveness on intermediate-level Sudoku puzzles from publicly available sources, involving over 200 Ising spins with long-range couplings dictated by constraint satisfaction. We then apply the algorithm to MaxCut problems from the Biq Mac library, successfully solving instances with up to 251 nodes and 3,265 edges. We discuss the advantages of this quantum-inspired approach, including its scalability, generalizability, and suitability for industrial-scale QUBO applications.

Dynamic Magnetic Characteristics and Their Dependences on Servicing Conditions of Fe-Based Nanocrystalline Alloy Cores Modulated via Transverse Magnetic Field Annealing

This study presents a novel queuing-theoretic framework to analyze magnetohydrodynamic flow and reactive mass transfer in Casson fluid systems, particularly under conditions involving delays, interruptions, and recovery phases. The fluid is modeled as a non-Newtonian Casson fluid with yield stress, flowing over a vertical porous plate under the influence of a uniform transverse magnetic field. Transport and reaction processes are conceptualized as a two-stage queuing system, allowing the integration of real-world dynamics such as service delays, flow breakdowns, and mass reactivation events. The governing equations and boundary conditions are formulated using a birth–death transformation derived from queuing theory. Numerical simulations, conducted using MATLAB, reveal that magnetic effects and Casson fluid properties introduce substantial delays in both momentum and mass transport, ultimately reducing the overall efficiency of mass transfer. The findings provide meaningful insights for the design and optimization of microfluidic, electrochemical, and biomedical systems, where control over flow and reaction timing is critical. The proposed approach establishes a novel queuing-based paradigm for analyzing non-Newtonian transport behavior, allowing systematic prediction and control of delay-driven inefficiencies across a range of fluid engineering applications.

Abstract: This study presents a comprehensive computational analysis of blood flow resistance in a symmetrically stenosed artery under the influence of an external magnetic field—a scenario of growing clinical relevance due to the rising interest in magnetically assisted therapies. Modeling blood as a viscous, incompressible, and electrically conducting fluid with radially variable viscosity, the problem incorporates both geometric non-uniformity and magnetohydrodynamic effects through the inclusion of a transverse magnetic field. The governing equations, derived in cylindrical coordinates and non-dimensionalized using characteristic parameters, are solved using the Finite Difference Method, offering robust insights into velocity distributions and flow resistance. The results reveal that stenosis height alone significantly elevates resistance, while the presence of a magnetic field amplifies this effect nonlinearly, with higher field strengths causing pronounced suppression of axial velocity. Velocity profiles flatten and shear rates near the arterial wall intensify with increasing stenosis and magnetic influence, underscoring the synergistic impact of these parameters. This work not only advances our understanding of MHD- modulated hemodynamics but also provides a theoretical foundation for future biomedical applications such as targeted drug delivery, vascular diagnostics, and therapeutic flow control.

This work focuses on the magneto-optical behavior of one-dimensional ternary photonic crystals that incorporate extrinsically magnetized GaAs as a functional layer. In this context, we investigate the effect of an applied transverse magnetic field on the optical response and photonic band gap characteristics of the proposed structure. The transfer matrix method is utilized to analyze the optical response of the ternary structure. The ternary photonic crystal with extrinsically magnetized GaAs exhibits strong magnetic tunability. The photonic band gap shifts from 0.32 THz to 0.38 THz under an applied external magnetic field up to 0.75 T with 100% band gap modulation. The polarization mode also shifts within the range of 0.32-0.36/0.38 THz due to the anisotropic response of the magnetized GaAs. These results confirm the effectiveness of extrinsic magnetization for compact, dynamically tunable photonic devices. The proposed configuration thus provides an effective framework for developing multichannel and broadband transmission filters that can be adjusted in the terahertz domain.

Success of hitherto experiments carried out on PALS using disc-coil (DC) targets irradiated by 1ω and 3ω beam of the PALS laser, in which magnetic fields of axial geometry with respect to the laser beam axis and induction above 5T were generated, initiated a complementary research directed on creation of magnetized plasma jets in a magnetic field with transverse geometry of force lines in relation to the laser direction. This configuration is important for implementation of inertial fusion by magnetic implosion. In order to understand the influence of the transverse magnetic field on the emission parameters of hot electrons (HE) and ions from the ablation plasma, innovative disc-coil targets (DCT-DC) were used, consisting of a Cu disk coupled with a system of two coils. Comprehensive diagnostics included 2D and 1D space-time resolved imaging of the Cu Kα line emission, a multichannel magnetic electron spectrometer was used to measure the angular distribution of the HE energy spectra. Ion collectors, target current probes, X-ray spectroscopy, and plasma visualization in the soft X-ray range using a 4-frame X-ray camera were used as additional diagnostics. To characterize the plasma streams created under Cu-discs irradiation by laser beams and to determine the regions with electron density corresponding to the most probable mechanisms of the HE generation, were defined by 3-frame complex interferometry. Numerical simulations of experimental results based on the three-dimensional PIC code EPOCH provided a basic insight into mechanisms of HE propagation in a transverse magnetic field. The performed experiments demonstrated that the presence of the transverse magnetic field leads to a spatial broadening of the HE emitting region and to an increase of the HE energy, both in the backward and forward direction from the target. The increased fluxes of higher energy HEs observed at 1ω irradiated targets agree with results of simulations.

Magnetic fields can be used to control the process of magnetic fluid dispersion in microfluidics. Here we demonstrate a method for generating magnetic fluid droplets of a given size and shape in a microfluidic chip with a flow-focusing configuration under the influence of a transverse magnetic field. The results of the study show that a magnetic field can have a significant impact on ferrofluid dispersion. At low volumetric flow rates of the continuous phase, magnetic force plays a primary role in ferrofluid dispersion due to disturbances on the magnetic fluid surface. Furthermore, the droplet diameter decreases with increasing magnetic field Dd ∼ H-1/3. At high volumetric flow rates of the continuous phase, shear stress plays a primary role in ferrofluid dispersion. In this case, the droplet diameter depends on the continuous phase velocity according to the law Dd ∼ u-1. The magnetic field and the volumetric flow rate of the continuous phase affect not only the liquid dispersion process but also the coalescence and deformation of droplets. The pressure gradient in the channel and the magnetic field contribute to droplet deformation. The thickness of the deformed droplet decreases with increasing volumetric flow rate according to the law l ∼ Q-1. The non-uniformity of the velocity field distribution over the channel thickness is responsible for droplet coalescence. The magnetic field, on the contrary, prevents droplet coalescence. These findings open up new possibilities for generating soft magnetic robots of a given size and shape.