This paper presents an experimental investigation of magnetic reconnection between two laser-produced expanding plasmas, focusing on the quantitative evaluation of the reconnection rate and energy conversion under varying initial conditions. By changing the separation distance between the drive laser focal spots (1 mm and 2 mm), we systematically controlled the inflow parameters. The reconnection region was probed using a two-directional laser Thomson scattering (LTS) system, which simultaneously measured the local plasma parameters parallel to the outflows and along the current sheet. Based on our established method incorporating macroscopic energy and mass conservation laws to derive the upstream magnetic field directly from LTS spectra, we characterized the temporal evolution of the current sheet and the reconnection rate. The larger spot separation allows the plasma bubbles to expand for a substantially longer time before the formation of a reconnection current sheet, resulting in different upstream conditions. Nevertheless, both configurations yielded comparable upstream magnetic fields and reconnection rates. These results suggest that the reconnection rate is relatively insensitive to the global inflow conditions and is primarily controlled by the local physics of the reconnection layer once a current sheet is formed.

Equations describing evolution of the velocity of a rarefied ion beam in a plasma with ion-acoustic turbulence are derived and solved. An ion beam with velocity $u$ greater than the sound speed $v_s$ decelerates due to Cherenkov radiation of ion-acoustic waves. Conversely, a beam with $u<v_s$ accelerates to a velocity $\sim v_s$ due to Cherenkov interaction with field beats at a difference frequency of ion-acoustic waves. The acceleration of a slow beam is accompanied by anisotropic turbulent heating of beam ions. Characteristic deceleration (or acceleration) distances of beam ions are obtained.

A dusty plasma cloud hosting a counter-rotating vortex lobe pair is driven through controlled neutral-gas pressure ramps spanning nearly an order of magnitude in rate. The transient response is characterized by the longitudinal transport exponents ${\alpha }_{\mathrm{L}}$ and ${\alpha }_{\mathrm{R}}$, extracted from mean-squared displacements evaluated in the cotranslating frame of each lobe, with cluster-bootstrap confidence intervals. At baseline the two lobes are dynamically inequivalent, with a statistically confirmed asymmetry $\mathrm{\Delta }\alpha ={\alpha }_{\mathrm{R}}-{\alpha }_{\mathrm{L}}<0$ in all four experiments. The pressure ramp drives the exponents toward equalization and ultimately inverts the asymmetry. The inversion is completed within the ramp only for the gentlest forcing, and is deferred to the end of the forcing interval, or beyond it, as the ramp rate increases. A force-scale analysis shows that the per-particle neutral drag remains below the static levitation-force scale, but increases systematically with ramp rate and produces millimeter-scale horizontal advection of the cloud. The behavior is organized by a Deborah number $\mathrm{De}=T_{\mathrm{rot}}/{\tau }_{\mathrm{ramp}}$: the normalized inversion time increases with $\text{De}$ across the four experiments and approaches the end of the ramp for the fastest protocols. These results identify the vortex lobe pair as a rate-dependent, kinetically gated structure and connect its dynamics to the broader phenomenology of driven viscoelastic soft matter.

We numerically examine a binary system of particles with repulsive interactions, where one species is driven by a rotating drive and the other is subjected either to a constant drive in a fixed direction or to a rotating drive that is out of phase with the first species. As a function of rotation frequency, we find a variety of order-disorder transitions and pattern-forming states, including density-modulated stripes, partially jammed states, phase-separated fluids, and mixed fluids. When one species has a constant drive and the drive on the other species is rotated at low frequencies, the system switches between different pattern-forming phase-separated lanes including density-modulated stripes and partially jammed states, similar to what is observed for oppositely driven colloids. The lanes tend to align with the net direction of rotation, resulting in a series of order-disorder switching transitions. The transport curves show abrupt jumps up or down at the transitions, which also correspond with changes in the topological order. We find similar switching transitions when both species rotate out of phase with each other. For intermediate driving frequencies, the system becomes increasingly fluidlike and the laning behavior is lost. At high frequencies, however, the system can again exhibit patterned flow when the rotation orbits become smaller than the average spacing between particles. The switching is reduced when a finite temperature is included, but even for temperatures at which the uniform equilibrium bulk system is liquid, the partially jammed state can generate local density enhancements that lead to recrystallization. We demonstrate the pattern-switching behavior for systems with different screened repulsive interaction potentials.

In the supercritical fluid (SCF) region, at temperatures and pressures above the critical point, the thermodynamic singularity separating liquids and gases no longer exists. Recent arguments based on thermodynamics and critical scalings have revived the proposal that the SCF constitutes an intermediate state of matter, separated from the liquid and gas by two supercritical boundaries, the $L^{\pm }$ lines. However, until now, the nature of the supercritical state and the physical signatures of these boundaries have remained elusive. Here, we demonstrate that the SCF is characterized by distinct structural, transport, and dynamical behavior. Specifically, the spatial arrangement of particles—captured by the radial distribution function—as well as the diffusion coefficient, shear viscosity, and velocity autocorrelation function in the SCF regime are qualitatively different from those in both the liquid and gas states and exhibit physical signatures upon crossing the $L^{\pm }$ lines. Our theoretical predictions are supported by molecular dynamics simulations of argon and are further supported by existing experimental evidence. These results provide a clear physical foundation for a refined phase diagram of matter in the supercritical region, comprising three distinct states—gas, supercritical fluid, and liquid—separated by two crossover boundaries obeying universal scaling laws.

We develop a systematic extension of mode-coupling theory that incorporates critical dynamical fluctuations. Starting from a microscopic diagrammatic theory, we identify dominant classes of divergent diagrams near the mode-coupling transition and show that the corresponding asymptotic series dominates the mean-field prediction below an upper critical dimension $d_c=8$. To resum these divergences, we construct a mapping to a stochastic dynamical process in which the order parameter evolves under random spatiotemporal fields. This reformulation provides a controlled, fully dynamical derivation of an effective theory for $\beta$ relaxation that remarkably coincides with stochastic beta relaxation theory [T. Rizzo, Long-wavelength fluctuations lead to a model of the glass crossover, Europhys. Lett. 106, 56003 (2014)]. All coupling constants of the latter theory are expressed microscopically in terms of the liquid static structure factor and are computed for the paradigmatic hard-sphere system in the Percus-Yevick approximation. The analysis demonstrates that critical fluctuations alone restore ergodicity and replace the putative mean-field transition with a smooth crossover. Our results establish a predictive framework for structural relaxation beyond mean-field.

We numerically study the flow of dense granular materials between parallel plates driven by an external force. The granular materials form a jammed solidlike state when the external force is below a critical force, while they flow like fluids above the critical force. The transition is characterized by the mass flux. The critical force depends on the average packing fraction and the distance between the plates. The scaling laws for the critical force and the mass flux are theoretically predicted based on a continuum model, and are numerically verified.

The directed motion of active colloids is governed by spatial variations in surface chemistry that generate effective interfacial flows, yet the resulting slip distributions remain extremely difficult to measure directly. We introduce a physics-informed neural network framework that infers the slip distribution driving propulsion from partial observations of the surrounding flow. By combining partial fluid-velocity measurements with the Stokes equations and boundary constraints, the method reconstructs both the near-surface slip and the full velocity field. Validation against analytical solutions and boundary element method calculations for canonical active colloid models shows quantitative agreement in both unbounded and confined geometries. Systematic tests identify the conditions under which the reconstruction degrades as measurement availability decreases or noise increases, while comparison with radial-basis-function interpolation demonstrates the importance of the governing equations for recovering the data-free near-surface flow. Crucially, the framework recovers the surface slip even when no flow data are available near the particle, demonstrating that accessible bulk measurements encode the effective surface slip associated with active motion.

We solve exactly the transient two-dimensional advection diffusion problem generated by one and two semi-infinite internal Dirichlet lines, representing slender dendrites advancing into a supersaturated liquid while fixing the solute concentration on their surfaces. For a single dendrite, the mixed boundary value problem is reduced to a Wiener-Hopf equation, factorized explicitly, and inverted to the time domain by the Cagniard-de Hoop method, yielding the single-layer density in closed form in terms of the complex error function. For two parallel dendrites separated by a lateral distance $h$, the interaction enters through the transcendental kernel ${(1+e^{-\kappa h})}^{-1}$, whose lower Wiener-Hopf factor is represented by a logarithmic Cauchy integral, and the resulting finite distance feeding field is reduced to a regularized oscillatory integral. The exact two-dendrite solution reveals a structural obstruction to purely local growth laws: the leading inverse square-root tip singularity is universal, with identical amplitudes for both dendrites independently of spacing, even though the neighbor modifies the feeding field at every finite distance behind the tip. Competition therefore cannot be encoded in any local tip amplitude alone. This obstruction forces a nonlocal coupling variable, which we identify as a finite tip zone functional that retains the subleading near tip structure responsible for competitive depletion. The interaction further resolves into a discrete hierarchy of exponentially screened modes with dominant screening length $h/\pi$, which sets the natural scale of competitive suppression. These exact transport results provide the analytical backbone for a reduced theory of dendrite arrest and winner selection, and are validated against independent finite-difference computations.

A solidifying dendrite advancing toward an oblique impermeable wall senses the wall through reflection of its own diffusive depletion field. The strength of this reflection depends on both wall obliquity and the unsteady kinematics of the closing gap, and cannot be captured by any quasistatic frozen offset construction. We solve the moving boundary diffusion problem exactly in the laboratory frame (wall fixed, dendrite advancing at constant speed) by recasting it as a Wiener-Hopf-Hankel system on a pair of spectral branches. The resulting upper triangular operator is inverted sequentially: first as a Fredholm integral equation on the lower branch, then as a scalar Wiener-Hopf problem on the upper branch, reaching a closed form solution via Cagniard-de Hoop. A Padé-Abrahams rational reduction of the spectral radical reduces the entire scheme to a low cost algebraic system at each Laplace node. The exact unsteady solution inverts the classical starvation picture. Measured against an isolated dendrite at the same elapsed time, the wall correction is weakly suppressive while the tip is more than about two diffusion lengths from the wall, where the reflected depletion returns with little retardation and acts as ordinary blockage, but the suppression never exceeds one percent. As the gap closes the correction changes sign and the feeding rises to 31 percent above the isolated reference at grazing incidence, because the reflected field carries a memory of wider past gaps and delivers more solute than the instantaneous geometry would allow. The enhancement is governed by the oblique Péclet number ${\text{Pe}}_{\theta }=v{d}_{0}sin\theta /D$ and is strongest at grazing incidence, where it exceeds the preceding suppression by a factor of 30.

We show that stochastically driven nonequilibrium conserved growth models admit generic strong coupling phases for sufficiently strong nonlocal chemical potentials underlying the dynamics. The models exhibit generic roughening transitions between perturbatively accessible weak coupling phases satisfying an exact relation between the scaling exponents in all dimensions $d$, and strong coupling phases. In dimensions at or below the critical dimension $d_c$, the latter phases are unstable and argued to be crumpled, and thus distinct from the well-known strong coupling rough phase of the Kardar-Parisi-Zhang equation in dimensions $d\ge 2$. At $d_c$, conventional spatiotemporal scaling in the weak coupling phase is logarithmically modulated and are exactly obtained.

Measuring transport coefficients at the microscale remains challenging, often relying on indirect methods that require modeling and calibration. This article derives universal asymptotic forms for the autocorrelation and relative uncertainty of local probe measurements in dilute diffusive systems. Valid both at and far from equilibrium, these forms directly connect microscopic measurements to the effective diffusivity. Indirect methods such as dynamic light scattering and fluorescence correlation spectroscopy can therefore serve as asymptotically direct probes applicable to active and other microscopically nondiffusive systems. Simulations across several models and observables confirm the broad applicability of these predictions to a variety of probes.

Estimating entropy production in continuous systems that can only be observed with a limited resolution remains an open problem in stochastic thermodynamics. Existing estimators based on the measurement of waiting-time distributions either require the detection of Markovian events, which uniquely determine the state of the system, or assume a discrete underlying dynamics. We present a novel estimator that relies solely on the detection of a single particle leaving or entering regions, or crossing manifolds, in continuous space. This estimator is based on the frequency and the duration of transitions between such events. We derive this bound by introducing two kinds of discretization of space. Finally, we compare our novel bound to the thermodynamic uncertainty relation improved by correlations using simulations of a Brownian vortex, and we discuss its relation to other lower bounds to entropy production.

We conduct numerical simulations of a noisy generalized Kuramoto-Sivashinsky system under optimal control. The cost functions are kinetic energy and permutation entropy, which are designed to reduce the kinetic energy and the permutation entropy, respectively. The results demonstrate that kinetic-energy-based control strongly suppresses the structures and drives the system into a trivial state. In contrast, the permutation-entropy-based control preserves nontrivial structures, although the reduction in kinetic energy is smaller and requires only slight actuation energy. These findings provide insight into designing control strategies for complex systems where both efficiency and functional richness are desired.

We investigate dust-acoustic rogue waves in a one-dimensional binary dusty plasma using analytical nonlinear Schrödinger equation theory and fully kinetic particle-in-cell simulations. Modulational instability initially drives nonlinear focusing and rogue-wave formation, consistent with fluid predictions. However, after the rogue-wave peak, the coherent structure collapses irreversibly due to kinetic effects instead of exhibiting periodic recurrence. The breakdown is caused by asymmetric kinetic heating between the two dust species. The lighter dust grains, owing to their lower inertia, absorb most of the wave energy through strong wave-particle interactions and develop non-Maxwellian energetic tails, while the heavy dust experiences only weak heating. In addition, the rogue-wave excitation time is highly sensitive to small changes in the imposed perturbation amplitude. These results demonstrate the kinetic and irreversible nature of rogue waves in realistic binary dusty plasmas.

Laser wakefield acceleration (LWFA) provides a compact platform for generating bright, ultrashort, and tunable x-ray betatron radiation. When the betatron oscillation wavelength matches the laser centroid oscillation period in a preformed plasma channel, resonance occurs, leading to a rapid amplification of the electron betatron oscillation amplitude and significantly increasing the photon energy and yield of the sources. However, nonideal conditions from laser-plasma interactions may drive electrons out of resonance rapidly. In this work we use particle-in-cell simulations and theoretical analysis to identify four distinct mechanisms that disrupt the resonant growth: the nonlinear focusing force at large radii, the dephasing between the wakefield and the electron beam, the acceleration or deceleration of the electrons, and the decay of the laser centroid oscillation amplitude caused by phase mixing among different laser slices. Detailed particle tracking reveals that a delicate balance between dephasing and acceleration can sustain electrons in resonance for an extended period. Building upon these physical insights, we optimize laser, electron beam, and plasma channels to significantly enhance the emitted radiation. These results provide valuable guidance for developing high-yield and high-energy betatron radiation sources based on LWFA.

We theoretically and experimentally investigate wave scattering in a single-column woodpile structure with impurities. This structure consists of slender cylindrical beams that support flexural bending modes, which are coupled strongly with propagating waves in the low-frequency regime (i.e., local resonance coupling). We examine the linear scattering of plane waves from single and double impurities in periodic configurations. When local resonance coupling is neglected, the double-impurity configuration exhibits reflectionless transmission, resembling the Ramsauer-Townsend (RT) resonance. Further analysis reveals that, under strong local resonance coupling, this behavior evolves into a Fano resonance, which features an asymmetric line shape with a sharp transition between transmission and reflection. However, as the RT resonance and the local resonance become spectrally closer, an analog of electromagnetically induced transparency (EIT) emerges, resulting from the balanced interference between the two modes. These distinct resonant behaviors can be tuned by varying the local resonance coupling strength, providing a controllable platform for macroscopic analogs of quantum wave interference. Potential applications include vibration isolation and wave-based switching devices.

The pore-surface and surface-surface correlation functions are structural characteristics that play an important role in theoretical materials science and in small-angle scattering theory. Symbolic expressions for the surface correlation functions are available only for very few models, and we here derive such expressions for the general class of dead-leaves models. Within these models, a two-phase pore-solid structure is created by sequentially and randomly filling space with porelike or solidlike grains that overlap any preexisting structure, in the same way that dead leaves fall on the ground. The obtained mathematical expressions are valid for any grain shape, in arbitrary dimension. The results are illustrated with monodispersed spherical grains as well as with a dead-leaves realization of a Debye random medium. In the latter case, the size distribution of the grains is designed to produce a structure having an exponential two-point correlation function. Compared to Debye random media obtained by numerical reconstruction, the dead-leaves structure has an almost identical surface-surface correlation function, but a distinctly different pore-surface correlation function with different average mean curvature of the pore-solid surface. Using the concepts introduced in the paper, we submit a general analytic expression for the pore-surface and surface-surface correlation functions of the Boolean model of interpenetrating grains, valid for arbitrary grains. We also derive general expressions for the surface correlation functions of mosaic structures.

One-dimensional alternating particle systems are widely used to study interconnections between the hydrodynamics of blast waves in a gas-like medium and the Newtonian dynamics of its corpuscular constituents. In this article, we study the model in which point particles with masses $m,\mu ,m,\mu ,\cdots , (m\ge \mu )$ are distributed on the positive half-line ${\mathbb{R}}_{+}$. Their dynamics are initiated by giving a positive velocity to the leftmost particle; in its course, the particles undergo elastic collisions. For this model with $m/\mu =2$, it has been established that the dynamics that start from random initial positions are consistent with predictions based on Euler's hydrodynamic equation. In particular, they have the following properties: (i) the position of the rightmost particle (shock front) evolves as $t^{\delta }$ with $\delta <1$; (ii) recoiled particles behind the front enter the negative half-axis; and (iii) particles with locations $x\le 0$ move ballistically and eventually take over the total energy of the system. In this paper, we present numerical and analytical results for the dynamics of this model with nonrandom (typically equidistant) initial positions and various values of $m/\mu$. For $m/\mu =2$ and equidistant initial positions, our results qualitatively agree with those just mentioned. At the same time, we found an infinite family of numbers $\left\{{\mathcal{M}}_k\right\}$ such that, for $m/\mu ={\mathcal{M}}_k$, the hydrodynamic behavior mentioned changes drastically to the following. At each moment, only a single triplet $m,\mu ,m$ is in motion, whereas all other particles are at rest. In the moving triplet, two heavy particles move to the right, while the lighter particle oscillates between them, transferring energy and momentum to the right. As a result, the shock front moves ballistically with an average velocity equal to the initial one. Such a ‘staggering domino-like’ picture is obtained as an exact solution, which yields, in particular, explicit formulas for ${\mathcal{M}}_k$ and the particle velocities and positions. Its details and importance in a wider context are also discussed.