Membrane structures play a central role in cellular processes, adopting morphologies such as sheetlike cisternae of the endoplasmic reticulum and mitochondrial cristae, tubular extensions of the ER and neurons, and cup-shaped double membranes of autophagosomes. Theoretical descriptions of these fundamental geometries typically require solving singular nonlinear shape equations or performing computationally intensive coarse-grained and triangulated vesicle simulations. Here, we introduce a simple analytical framework that provides closed-form expressions for the key shape properties of tubes, sheets, and cups, including volume-to-area ratio, bending energy, and asymmetry. This approach eliminates the need for complex mathematical or numerical methods while retaining quantitative accuracy. We validate and modify our results by direct comparison with accurate results form Monte Carlo minimizations of triangulated vesicles. The framework thus offers a fast and accessible method for estimating membrane shape energetics, providing a practical tool for studies of cellular and biomimetic membrane systems.

The process of direct laser acceleration of plasma electrons is considered in a strongly magnetized plasmoid with the magnetic field strength allowing for reaching the autoresonance without any special injection conditions. The plasmoid may be optically created by irradiation of specially designed targets with an auxiliary intense laser beam at the previous stage of interaction in a possible all-optical setup. Specifics of the acceleration in the strongly magnetized plasma solenoid, such as the magnetic field profile and its finite size, may be critical for the resonant processes where even a small deviation of the parameters destroys the matching conditions. The process of the autoresonant electron acceleration is analyzed for different configurations inherent in the possible realizations of the setup, and estimates for the efficiency of acceleration and resonance magnetic fields are proposed. Based on the provided analysis, it may be concluded that despite the modifications of the autoresonance conditions and the presence of collective effects, the generation of energetic electron bunches in a realistic setup may be both possible and effective.

The trajectory of light rays propagating through a nonuniformly moving anisotropic medium is determined by considering the Fresnel drag experienced by the wave at each point along the ray. By showing that symmetries in the velocity field manifest as symmetries in the effective wave index representing the moving medium, methods classically employed to model gradient-index media are then used to obtain analytical forms for the ray trajectory. When applied to isotropic media, the results are verified to be consistent with those obtained using an optical (Gordon) metric. The potential of this method to model light rays in anisotropic media is finally demonstrated by considering waves in a nonuniformly moving magnetized plasma, exposing how nonuniform motion and anisotropy can compete with one another.

We develop a wavepacket molecular dynamics framework for modeling the structural properties of partially ionized dense plasmas, based on a chemical model that explicitly includes bound state wave functions. Using hydrogen as a representative system, we compute self-consistent charge state distributions through free-energy minimization, following the approach of Plummer et al. [Phys. Rev. E 111, 015204 (2025)]. This enables a direct comparison of static equilibrium properties with path-integral Monte Carlo data, facilitating an evaluation of the model's underlying approximations and its ability to capture the complex interplay between ionization and structure in dense plasma environments.

Beyond beam energy and energy spread, transverse beam parameters are crucial in laser-plasma accelerator projects that aim to deliver a high-quality beam to a user's community. In this article, transverse beam physics is thoroughly studied throughout an entire plasma stage, including a plasma density plateau surrounded by density up-ramp and down-ramp. Physical mechanisms, analytical calculations, and numerical simulations are employed to study the evolution of the beam Twiss parameters and emittance. The key parameters and key roles of the different plasma sections are identified. Guidelines are provided for efficiently minimizing emittance growth all along the plasma acceleration stage and the coupling with upstream and downstream transport lines.

We report computer simulations on the adhesive loose packing (ALP) limit of monodisperse axisymmetric ellipsoids, spherocylinders, and polymers by the random ballistic deposition method with the hit-stick-freeze assumption. The mean-field results demonstrate that the global packing fraction reaches a maximum value of 0.1469 for spheres, and it is nicely correlated with the aspect ratio in the 1 and $-2$ power-law relations for extremely oblate and prolate particles, respectively. For a given aspect ratio $\lambda$, the density follows the sequence of decreasing packing fraction: spheres $>$ prolate ellipsoids $>$ spherocylinders $>$ polymers for $\lambda <3$, or spheres $>$ spherocylinders $>$ prolate ellipsoids $>$ polymers for $\lambda \ge 3$. In addition, we highlight that the local coordination number excellently follows the normal distribution with a universal mean value of 2.001, regardless of the particle type and aspect ratio. The standard deviation is 0.730 for spheres, which increasingly approaches the asymptotic values of 0.850 for $\lambda \to 0$ and 1.112 for $\lambda \to +\infty$. Furthermore, we find that the radial distribution function is dominantly governed by the first contact shell with three distinct features, corresponding to the local minor-to-minor, minor-to-major, and major-to-major contacts between two particles. Finally, we present the universal correlation forms for both the global packing fraction and the standard deviation of coordination number, covering the wide aspect ratio range of 0.003–60 for ellipsoids and 1–60 for spherocylinders and polymers. We emphasize that the ALP limit represents the minimum-density state achievable via random ballistic deposition of strongly adhesive particles, while looser structures may be obtained by other cluster aggregation processes.

We investigated the correlation dynamics of colloidal particles in crowded, aqueous, and quasi-two-dimensional environments. Using optical microscopy, we analyzed variations in two-particle displacement and direction correlations, estimating their respective ranges of influence. Our results show that microscopic colloidal particles significantly impact the dynamics of their neighbors, with the strength of correlations diminishing with increasing distance, following a power-law decay. Increasing the particle area fraction enhances these correlation ranges. Introducing localized active fluctuations via enzyme-substrate reactions extends these ranges even further. We performed overdamped Langevin dynamics simulations, which qualitatively supported our experimental findings. This study advances our understanding of active matter systems by revealing how crowding and enzyme-driven active fluctuations can modulate particle correlations. These insights pave the way for improved design and control of colloidal assemblies in complex environments, with potential applications in materials science, biophysics, and nanotechnology.

In our previous work [Phys. Rev. E 104, 014124 (2021)], we developed a method for analyzing classical liquids using the functional renormalization group (FRG) without relying on a hard-core reference system. In this paper, we extend this method to three-dimensional liquids. We describe an efficient approach for performing the spatial integrals that appear in the renormalization group equations, which is essential for realizing numerical calculations in three dimensions. As a demonstration, we present its application to the Lennard-Jones liquids. Through calculations of thermodynamic quantities, we find that FRG preserves thermodynamic consistency (TC) better than traditional integral-equation methods such as the hypernetted-chain, Percus-Yevick, and Kovalenko-Hirata closures. Taking the molecular dynamics results as a benchmark, we also show that FRG can achieve an accuracy comparable to that of integral-equation methods that incorporate TC, such as the Rogers-Young closure. We further assess the accuracy of the pair distribution function and examine whether our method remains applicable below the critical temperature. Our results demonstrate that FRG provides a new method for describing classical liquids with accuracy comparable to modern liquid theories.

We introduce proxitaxis, a simple search strategy where the searcher has only information about the distance from the target but not the direction. The strategy consists of three crucial components: (i) local adaptive moves with a distance-dependent diffusion coefficient, (ii) intermittent long-range returns via stochastic resetting to a certain location ${\vec{R}}_0$, and (iii) an inspection move where the searcher dynamically updates the resetting position ${\vec{R}}_0$. We compute analytically the capture probability of the target within this strategy and show that it can be maximized by an optimal choice of the control parameters of this strategy. Moreover, the optimal strategy undergoes multiple phase transitions as a function of the control parameters. These phase transitions are generic and occur in all dimensions.

The diffusion of micro- and nanoswimmers in a fluid, confined within irregular structures that impose entropic barriers, is often modeled using overdamped active Brownian dynamics, where viscous effects are paramount and inertia is negligible. Here, we numerically investigate the diffusive behavior of chiral self-propelled particles in a two-dimensional asymmetric channel subjected to an external torque arising from a gravitational field. We reveal the emergence of resonant diffusion when the external torque $\omega$ approaches the intrinsic angular velocity ${\omega }_0$ of particles. This resonance manifests as a pronounced accumulation of particles near the upper-left corner of the channel, accompanied by an enhanced peak in the effective diffusion coefficient. In particular, it is observed only for low rotational diffusion rates and does not persist beyond moderate values of ${\omega }_0$. Prominent transport features, such as rectification at low values of $\omega$, a monotonic increase in average velocity with $\omega$, and a nonmonotonic response of transport characteristics (average velocity and effective diffusion coefficient) as a function of the rotational diffusion rate near the resonance point, are explained. Furthermore, we show that the transport characteristics depend strongly on the aspect ratio of the channel. For instance, the enhanced diffusion peak becomes more pronounced with increasing aspect ratio, and the average velocity saturates at higher values for wider bottleneck openings. It is conceivable that these findings have a great potential for developing microfluidic and laboratory-on-a-chip devices for particle separation, targeted drug delivery, and advanced active materials.

Diffusion in a confining potential offers a minimal setting to understand the interplay between random motion and deterministic forces driving a particle towards a focal point or potential minimum. In continuous space and time, two extensively studied examples are Brownian motion in a linear (V-shaped) or a quadratic (U-shaped) potential. The deterministic bias towards the minimum is represented, respectively, by a constant force for the former and by an elastic restoring force that increases proportionally with distance for the latter. Surprisingly, unlike Brownian walks, random walks under focal point potentials in discrete space and time have received little attention. Here we bridge this gap by analyzing the dynamics of lattice random walkers in the presence of a V-shaped potential, both in a finite and an infinite spatial domain, and a finite U-shaped potential. For the V potential in unbounded space, we find the generating function of the occupation probability and analyze the time dependence of the mean number of distinct sites visited, demonstrating that its long-time growth is logarithmic. We also study the first-passage probability and show that its mean may display a minimum as a function of bias strength, depending on the location of the initial and target sites relative to the focal point. Qualitatively similar dependencies in the first-passage probability and its mean appear for the finite U potential. As a comparative analysis to the U potential, we construct the bounded V potential and superimpose in both cases a resetting process, in which the walker returns at random times to a site distinct from the focal point with some probability. We quantify the different effects of resetting on the steady-state probability and the first-passage dynamics in the two cases and show that a motion-limited regime emerges even for relatively moderate resetting probabilities.

The dynamics of the spins in the Ising model are analyzed using a virtual walk scenario. The system is quenched from a very high temperature to a lower one using the Glauber scheme in one and two dimensions. A walk is associated with each spin which evolves according to the current state of the spin. The probability distribution of the displacement of the walker is calculated, which shows a distinct change as the temperature is increased. The average displacement as a function of time shows a nonequilibrium region stretched over a much longer time interval compared to the bulk magnetization. Nevertheless, one can still detect a time-dependent estimate of the critical point determined by two different methods. In addition, we introduce a virtual walk generated from the local energy of individual spins. Finite-time scaling of the different quantities estimated in two dimensions shows excellent consistency with the values of the known critical exponents.

Phase-space features of a reduced version of the Toda-like Hamiltonian $\mathcal{H}(x,k)$, written in a form constrained by the condition ${\partial }^2\mathcal{H}/\partial x\partial k=0$, with $x$ and $k$ as canonically conjugate variables, are analyzed in terms of Wigner currents. For Wigner currents convoluted with either thermodynamic or Gaussian ensembles, the underlying Hamiltonian dynamics admits analytic corrections due to quantum distortions over the classical phase-space pattern, computed and interpreted through quantifiers of quantumness and stationarity. Notably, while emulating the Lotka-Volterra (LV) dynamics that describe ecological competition systems, the Toda-like classical dynamics allows for analytical solutions with computable periods corresponding to closed phase-space orbits of isotropic prey-predator population distributions. The essential conditions for understanding how classical and quantum evolution can coexist are provided at different scales of quantumness, driven by the associated convoluting ensemble parameter. In the case of Gaussian statistical ensembles, the exact profile of the quantum distortions over classical prey-predator phase-space trajectories is obtained nonperturbatively. Our results indicate that, besides the classical stability admitted by LV models, the Toda-like patterns also exhibit quantum stability. Therefore, this can be regarded as the first step as a predictive theoretical framework toward more robust descriptions of quantum patterns in competitive microscopic biosystems.

This study examines interscale energy transfer, conventionally denoted as the “energy cascade,” in forced homogeneous isotropic turbulence. By employing spatial filtering techniques, the turbulent kinetic energy is decomposed into distinct large- and small-scale components, as well as local- and subfilter-scale constituents—specifically encompassing large-scale, small-scale, subfilter-large-scale, and subfilter-small-scale terms. Transport equations for each component are derived to establish an analytical framework elucidating the mechanisms governing cross-scale energy transfer. Within this framework, energy is primarily transferred scale-by-scale from the large-scale and subfilter-small-scale components to the small-scale and subfilter-large-scale portions of the turbulent kinetic energy. Building upon this framework, the following results and discussions are presented. First, the scaling laws governing interscale energy transfer and viscous dissipation rates are elucidated across both the dissipative and inertial subranges. Second, via Leonard decomposition, the subfilter-large-scale and subfilter-small-scale stress tensors are partitioned into Leonard, cross, and Reynolds components. In the dissipative range, interscale energy transfer is predominantly governed by the Leonard and cross-stress terms, whereas all three components contribute significantly in the inertial subrange, with their respective contributions quantitatively assessed. Third, the accuracy of several classical models in predicting interscale energy transfer rates—both from large to subfilter-large scales and from subfilter-small to small scales—is validated. Finally, investigation of extreme dissipation events reveals substantial amplification at small scales and marked alterations in scaling behavior near the inertial subrange, which are closely associated with turbulent intermittency, as evidenced by probability density distributions.

The role of zonal flow (ZF) in the turbulence saturation of trapped electron modes (TEM) in magnetically confined plasmas is revisited. In this study, we examine ZF excitation and saturation mechanisms in TEM turbulence using detailed free-energy transfer diagnostics from nonlinear gyrokinetic simulations. When the ion channel becomes subdominant, electrons shift to transferring energy to the zonal component, which results in zonal flows always playing a significant though subdominant role, in the case of the temperature gradient driven TEM. The velocity-space structure of energy transfer reveals that trapped electrons directly couple to ZF. Regarding the saturation physics, the zonal flow advection, drift-wave–drift-wave interactions, and stable modes at the pump waves are compared. When ZF saturation is weak, drift-wave–drift-wave interactions play a larger role in maintaining turbulence saturation. The findings elucidate the roles of nonzonal to zonal flow coupling, stable modes, and nonzonal wave-wave interactions, and provide a basis for improving reduced models of turbulent transport.

Detailed investigation of the x-ray drive on the capsule at the center of the hohlraum is crucial to solve the “drive deficit” problem in inertial confinement fusion. A pioneering work for probing the drive flux at the hohlraum center by simultaneously measuring the re-emitted flux and shock velocity was reported [X. Xie et al., Phys. Rev. Lett. 128, 075001 (2022)]. However, in the last experiment only two discrete shock velocity values can be obtained, as the streaked optical pyrometer was employed. In this work, we present characterization of the time-dependent x-ray drive on the capsule by simultaneously measuring the time-dependent localized re-emitted flux and the time-dependent shock velocity. The time-dependent localized re-emitted flux was measured by the space-resolving flux detector, while the time-dependent shock velocity was obtained with the velocity interferometer system for any reflector. Two-dimensional radiation hydrodynamic simulations revealed that the time history of the re-emitted flux as well as the shock velocity can be well reproduced. This technique presented a way for the determination of the x-ray drive at the center of the cylindrical hohlraum as well as other novel hohlraums.

Within the equilibrium-diffusion approximation for radiation, we perform a linear stability analysis of the compressible Rayleigh-Taylor instability in a stratified, isothermal background. Radiation alters the growth rate by modulating the fluid's effective compressibility. Radiative diffusion enhances compressibility, driving the growth rate from the adiabatic toward the isothermal limit as the Péclet number $\mathrm{Pe}$ decreases. In contrast, radiation pressure reduces compressibility, steering the growth rate toward the incompressible limit as the Mihalas number $R$ decreases. These competing effects are governed by the key dimensionless groups $\mathrm{Pe}$ (convective versus diffusive transport) and $R$ (material versus radiation pressure). The impact of radiation is most pronounced at low Atwood numbers ($\mathrm{At}$), high stratification parameters ($\mathrm{Sr}$), or large interface thicknesses ($\delta$).

When subjected to cylindrical confinement, parts of topologically modified ring polymers can be localized along the long axis of the cylinder by introducing loops within the ring polymer. This was achieved by introducing cross-links between specific monomers of the polymer. The loops formed as a result of this cross-linking has been termed as “internal loops” in this work. The emergent organization of the polymer segments occurs because of the entropic repulsion between these internal loops [Phys. Rev. E 106, 054502 (2022)]. These principles were used to identify the underlying mechanism of bacterial chromosome organization [Soft Matter 18, 5615 (2022)]. Here, we outline functional principles associated with entropic interactions, leading to specific orientations of the ring polymers relative to their neighbors in the cylindrical confinement. We achieve this by modifying the ring polymer topology by creating internal loops of two different sizes within the polymer, and thus create an asymmetry. This allows us to strategically manipulate polymer topology such that segments of a polymer face certain other segments of a neighboring polymer. The polymers therefore behave as if they are subjected to an “effective” entropic interaction reminiscent of interactions between Ising spins. But this emergent spatial and orientational organization is not enthalpy-driven. We consider a bead spring model of flexible polymers with only repulsive excluded volume interactions between the monomers. The polymers entropically repel each other and occupy different portions of the cylinder, and moreover, the adjacent polymers preferentially reorient themselves along the axis of the cylinder. We further substantiate our observations by free-energy calculations. To the best of our knowledge, this is the first study of the emergence of effective orientational interactions by harnessing entropic interactions in flexible polymers. The principles elucidated here could be relevant to understand the interactions between different sized loops within a large chromosome.

Strain localization in granular materials arises from complex microscale dynamics, including intermittent particle rearrangements and spatiotemporally correlated deformation. While dynamic heterogeneity (DH) and dynamic facilitation (DF) have been widely studied in two-dimensional amorphous materials, their prevalence in three-dimensional (3D) granular systems remains unclear. Here, we performed a 3D triaxial compression test with in-situ x-ray computed tomography to track particle-scale kinematics across small and large strain increments. We analyzed deviatoric strain, volumetric strain, and nonaffine motion fields, computed four-point spatial dynamic correlation functions to probe DH, quantified DF through a facilitation ratio, and assessed the temporal persistence of local dynamics using four-point temporal dynamic correlations. Across large strain increments, DH and DF emerge strongly in the transition regime between the initially elastic response and the critical state regime, but weaken or become statistically insignificant within the shear band at the critical state, indicating a qualitative change in collective deformation dynamics upon localization. In contrast, under small increments, both measures are suppressed across all regimes. These results demonstrate that correlated dynamics depend strongly on both strain increment and deformation regime. This work provides a comprehensive investigation of DH and DF in 3D granular materials and highlights their strain-increment- and regime-dependent behaviors, establishing a connection to glassy dynamics in amorphous solids.