# gst: stability of particle clusters bound by capillary bridges in extensional flow.

<< ️Capillary suspensions are commonly encountered in a wide array of applications, but their stability in flow is not fully understood. Here, (AA) investigate the stability of a two-particle capillary cluster in extensional flow using a combination of theory and experiments. >>

<< ️A linear stability analysis reveals the existence of a critical capillary number Ca_𝑐=(8/45)⁢cos⁡𝜃 that depends only on the contact angle 𝜃. For Ca>Ca_𝑐, clusters are unconditionally unstable, regardless of initial conditions. For Ca <Ca_𝑐, a nonlinear analysis shows the existence of a Ca-dependent minimum interparticle separation beyond which breakup occurs. >>

<< ️The analytical model further supports the experimentally observed slowdown in relaxation dynamics. Theoretical predictions are supported by precise flow experiments using a Stokes trap, where active flow modulation is used to stabilize an initially unstable cluster in extensional flow. Overall, these (AA) results provide a quantitative understanding of capillary suspension stability in flow. >>

Sagar Chaudhary, Dimitrios Fraggedakis, Charles M. Schroeder. Stability of particle clusters bound by capillary bridges in extensional flow. Phys. Rev. Fluids 11, L032301. Mar 17, 2026.

https://journals.aps.org/prfluids/abstract/10.1103/g9nd-jlc9

Also: particle, instability, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particle, instability, flow instability,  capillary interactions, colloids, suspensions.

# gst: redirecting counter-moving swarms through collision.

<< ️Multi-swarm systems, where two or more swarms of mobile agents occupy the same region of space with different parameters and goals, occur in a variety of biological, engineering, and defense applications. Composites of multiple swarms can produce hybrid spatiotemporal patterns, which compared to single swarming systems, are relatively unexplored. >>

<< ️In this work, (AA) develop a framework for studying the collision of counter-moving swarms, each with its own preferred, stable velocity before collision. (They) show that redirection of such swarms after collision occurs when a stable velocity synchronized state of the multi-swarm composite exists. Using a rigid-body approximation, (They) are able to extract how scatter-redirection transitions scale with swarm parameters in a variety of scenarios from reciprocal and non-reciprocal systems to symmetric and antagonistic parameter values. (They) results compare well to simulations of both particle modeled agents and wheeled robots. >>

Jason Hindes, Chinthan B. Prasad, Loy McGuire, et al. Redirecting counter-moving swarms through collision. arXiv: 2603.12002v1 [nlin.AO]. Mar 12, 2026.

https://arxiv.org/abs/2603.12002

Also: swarm, swarmalators, particle, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, swarms, particles, transitions, scatter-redirection transitions, multi-swarm systems, collisions, collision of counter-moving swarms.

# gst: from fluttering to drifting: inertialess sedimentation of an achiral particle.

<< ️There has been much recent interest in the chiral motion of achiral particles that sediment in a viscous fluid in a regime where inertial effects can be neglected. This occurs in a broad range of applications such as those involving biological objects like algae, ultrathin graphene flakes, or colloidal suspensions. It is known that particles with two planes of symmetry can be categorized as “settlers,” “drifters,” or “flutterers,” where the latter sediment along chiral trajectories despite their achiral shapes. >>

<< ️Previous work investigated the sedimentation of circular disks bent into a U-shape and identified them as “flutterers.” In this work (AA) analyze the change in behavior of such particles when (They) break one of their symmetries by pinching the disks isometrically along their axis, a shape change that can arise during the sedimentation of thin elastic sheets. The “fluttering” behavior is found to be robust to such shape changes, with the trajectories now evolving toward helical paths. However, the behavior changes when the degree of pinching becomes too strong, at which point the particles become “drifters” which sediment steadily without rotation. >>

<< ️(AA) establish criteria for the transition between the two types of behavior and confirm (Their) predictions in experiments. Finally, (AA) discuss the implications of (Their) observations for the dispersion of dilute suspensions made of such particles. >>

Christian Vaquero-Stainer, Tymoteusz Miara, Anne Juel, et al. From fluttering to drifting: Inertialess sedimentation of an achiral particle. Phys. Rev. Fluids 11, 034102. March 10, 2026.

https://journals.aps.org/prfluids/abstract/10.1103/scj8-6lpf

Also: particle, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, behaviors, particles, achiral particles, settlers, drifters, flutterers.

# gst: dynamics of perturbed elliptical billiard tables.

<< ️Dynamical billiards consist of a particle on a two-dimensional table, bouncing elastically off a boundary curve. The state of the system is given by two numbers: one describing the location along the curve where the bounce occurs, and another describing the incoming angle of the bounce. Successive bounces define a two-dimensional area preserving map, and iterating this map gives a dynamical system first studied by Birkhoff. >>

<< ️One of the simplest smooth table shapes is that of an ellipse, in which case the dynamics of the billiard map is completely integrable. The longstanding Birkhoff conjecture is that elliptical tables are the only smooth convex table for which complete integrability occurs. >>

<< ️In this spirit, (AA) present an implicit real analytic method for iterating billiard maps on perturbed elliptical tables. This method allows (They) to compute local stable and unstable manifolds of periodic orbits using the parameterization method. Globalizing these local manifolds numerically provides insight into the dynamics of the table. >>

Patrick Bishop, Summer Chenoweth, Emmanuel Fleurantin, et al. Dynamics of perturbed elliptical billiard tables. arXiv: 2602.15272v1 [math.DS]. Feb 17, 2026.

https://arxiv.org/abs/2602.15272

Also: billiard, particle, bouncing, elastic, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, billiard, particles, bouncing, elasticity, perturbed elliptical table.

# gst: steady states in a model of opposing local and nonlocal hops.

<< ️(AA) study a one-dimensional lattice model of particles following hard-core exclusion and performing opposing local and nonlocal moves with probability 𝑝 and 1−𝑝, respectively. (Their) model shows the interesting feature that the direction of the particle current can be switched by simply changing the density 𝜌 of particles on the lattice. (They) study the dependence of current on 𝑝 as well as 𝜌 and present the separation of positive and negative current regions on a 𝑝−𝜌 plane. >>

<< ️Further, (They) study the effect of disorder on this model by introducing a single site with valvelike dynamics. The site allows only unidirectional, local outward motion with rate 𝑟. The interplay of the disorder strength 𝑟, particle density 𝜌, and probability 𝑝 leads to a rich possibility with four different kinds of shock phases in the steady state. >>

<< ️(They) study the shock densities using Monte Carlo simulations and mean field calculations. While (Their) mean field treatment describes the numerical results quite well qualitatively, (AA) see certain quantitative deviations. (They) try to understand these deviations using measures of correlation in the system and provide heuristic arguments for the mismatch. >>

Ankur Mishra, Apoorva Nagar. Steady states in a model of opposing local and nonlocal hops. Phys. Rev. E 113, 024113. Feb 10, 2026.

https://journals.aps.org/pre/abstract/10.1103/66lp-n7hv

Also: particle, disorder, transitions, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, disorder, phase transitions, shock phases, valvelike dynamics.

# gst: spatial self-organization driven by temporal noise.

<< ️The counterintuitive emergence of order from noise is a central phenomenon in science, ranging from pattern formation and synchronization to order-by-disorder in frustrated systems. While large-scale spatial self-organization induced by local spatial noise is well studied, whether temporal noise can also drive such organization remains an open question. >>

<< ️Here, by studying interacting particle systems, (AA) show that temporally correlated noise can lead to a self-organized state with suppressed long-range density fluctuations, or hyperuniformity. Further, (They) develop a fluctuating hydrodynamic theory that quantitatively explains the origin of this phenomenon. >>

<< ️Finally, by casting the dynamics as a stochastic optimization problem, (They) show that temporal correlations lead to better solutions, akin to perturbed gradient descent in neural networks -- where noise is injected during training to escape poor minima. This reveals a striking correspondence between perturbed gradient descent dynamics on the energy landscapes of particle systems and the loss landscapes of neural networks. >>

Satyam Anand, Guanming Zhang, Stefano Martiniani. Spatial self-organization driven by temporal noise. arXiv: 2601.23098v1 [cond-mat.soft]. Jan 30, 2026.

https://arxiv.org/abs/2601.23098

Also: self-assembly, noise, order, disorder, disorder & fluctuations, particle, escape, network, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, self-assembly, noise, order, disorder, disorder & fluctuations, particles, networks, neural networks, spatial noise, temporal noise, noise-driven self-organization.

# gst: gigantic dynamical spreading and anomalous diffusion of jerky active particles.

<< ️Jerky active particles are Brownian self-propelled particles which are dominated by “jerk,” the change in acceleration. They represent a generalization of inertial active particles. In order to describe jerky active particles, a linear jerk equation of motion which involves a third-order derivative in time, Stokes friction, and a spring force (AA) combined with activity modeled by an active Ornstein-Uhlenbeck process. This equation of motion (They) solved analytically and the associated mean-square displacement (MSD) is extracted as a function of time. >>

<< ️For small damping and small spring constants, the MSD shows an enormous superballistic spreading with different scaling regimes characterized by anomalous high dynamical exponents 6, 5, 4, or 3 arising from a competition among jerk, inertia, and activity. When exposed to a harmonic potential, the gigantic spreading tendency induced by jerk gives rise to an enormous increase of the kinetic temperature and even to a sharp localization-delocalization transition, i.e., a jerky particle can escape from harmonic confinement. >>

<< ️The transition can be either first or second order as a function of jerkiness. Finally (AA)  shown that self-propelled jerky particles governed by the basic equation of motion can be realized experimentally both in feedback-controlled macroscopic particles and in active colloids governed by friction with memory. >>

Hartmut Löwen. Gigantic dynamical spreading and anomalous diffusion of jerky active particles. Phys. Rev. E 112, 045412. Oct 17, 2025.

https://journals.aps.org/pre/abstract/10.1103/976t-qry7

Also: particle, colloids, transition, escape, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, colloids, self-propelled particles, active Brownian particles, Jerky active particles, jerkiness, transitions, superballistic spreading, escape.

# gst: self-propelled particles undergoing cyclic transitions.

<< ️Cyclic transitions between active and passive states are central to many natural and synthetic systems, ranging from light-driven active particles to animal migrations. >>

<< ️Here, (AA) investigate a minimal model of self-propelled Brownian particles undergoing cyclic transitions across three spatial zones: gain, loss, and neutral regions. Particles become active in the gain region, passive in the loss region, and retain their state in the neutral region. By analyzing the steady-state behavior as a function of particle number and the size of the loss region, (They) identify a threshold particle number, below and above which distinct structural changes are observed. >>

<< ️Interestingly, below this threshold, increasing the particle number reduces the state-switching time (the time required for a particle to transition from active to passive and back to active). In contrast, above the threshold, further increases in particle number result in longer switching times. In the subthreshold regime, (They) analytical model predicts structural characteristics and switching dynamics that align well with simulations. Above the threshold, (They) observe an emergent clustering, with particles transitioning from passive to active states in close proximity. >>

Ye Zhang, Duanduan Wan. Self-propelled particles undergoing cyclic transitions. Phys. Rev. Research 7, L032040. Aug 21, 2025.

https://journals.aps.org/prresearch/abstract/10.1103/bxmn-hzwh

Also: particle, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particle, self-propelled particles, transitions, cyclic transitions. 

# gst: transition to chaos with conical billiards.

<< ️(AA) adapt ideas from geometrical optics and classical billiard dynamics to consider particle trajectories with constant velocity on a cone with specular reflections off an elliptical boundary formed by the intersection with a tilted plane, with tilt angle γ. >>

<< ️(They) explore the dynamics as a function of γ and the cone deficit angle χ that controls the sharpness of the apex, where a point source of positive Gaussian curvature is concentrated. >>

<< ️(AA) find regions of the (γ,χ) plane where, depending on the initial conditions, either (A) the trajectories sample the entire cone base and avoid the apex region; (B) sample only a portion of the base region while again avoiding the apex; or (C) sample the entire cone surface much more uniformly, suggestive of ergodicity. >>

<< ️The special case of an untilted cone displays only type A trajectories which form a ring caustic at the distance of closest approach to the apex. However, (They) observe an intricate transition to chaotic dynamics dominated by Type (C) trajectories for sufficiently large χ and γ. A Poincaré map that summarizes trajectories decomposed into the geodesic segments interrupted by specular reflections provides a powerful method for visualizing the transition to chaos. (AA) then analyze the similarities and differences of the path to chaos for conical billiards with other area-preserving conservative maps. >>

Lara Braverman, David R. Nelson. Transition to chaos with conical billiards. arXiv: 2508.02786v1 [nlin.CD]. Aug 4, 2025.

https://arxiv.org/abs/2508.02786

Also: billiard, particle, transition, chaos,  in https://www.inkgmr.net/kwrds.html 

Keywords: gst, billiard, particles, transitions, chaos. 

# gst: reversible switching due to attraction and repulsion: clusters, gaps, sorting, and mixing.

AA << ️describe a phase transition in continuum limits of interacting particle systems that exhibits a vertical bifurcation diagram. The transition is mediated by a competition short-range repulsion and long-range attraction. As a consequence of the transition, infinitesimal parameter variations allow switching between uniform distribution and clusters in single-species models, and between mixed and sorted states in multi-species contexts, without hysteresis. >>

Their << main technical contribution is a universal expansion for the size of vacuum bubbles that arise in this phase transition and a quantitative analysis of the effect of noise. >>

Arnd Scheel, Angela Stevens. Reversible switching due to attraction and repulsion: clusters, gaps, sorting, and mixing. arXiv: 2507.10406v1 [math.DS]. Jul 14, 2025.

https://arxiv.org/abs/2507.10406

Also: particle, bubble, noise, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, bubbles, noise, short-range repulsion, long-range attraction, phase transitions.

# gst: additional jamming transition in two-dimensional bidisperse granular packings.

AA << ️present a jamming diagram for two-dimensional bidisperse granular systems, capturing two distinct jamming transitions. The first occurs as large particles form a jammed structure, while the second, emerging at a critical small-particle concentration, 𝑋*_S ≈0.21, and size ratio, 𝛿*≈0.25, involves small particles jamming into the voids of the existing large-particle structure upon further compression. >>

<< ️Below this threshold, small particles fill voids within the large-particle network, increasing packing density. Beyond this point, excess small particles disrupt efficient packing, resulting in looser structures. These results, consistent with previous three-dimensional studies, demonstrate that the second transition occurs at a well-defined point in the (𝑋_S,𝛿) plane, independent of dimensionality, likely driven by the geometric saturation of available space around particles, void closure, and structural arrangement. >>

<< ️The second transition reveals that jamming in mixtures of differently sized particles does not occur through a single, unified process. Instead, it can involve multiple, distinct transitions, each associated with a specific particle size and contributing uniquely to the emergence of rigidity through excluded area effects and spatial organization. >>

Juan C. Petit, Matthias Sperl. Additional jamming transition in two-dimensional bidisperse granular packings. Phys. Rev. Research 7, L022073. Jun 20, 2025.

https://journals.aps.org/prresearch/abstract/10.1103/mtcv-dbpd

Also: particle, jamming, disorder, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, granular packing, jamming, disorder, transitions. 

# gst: nonstationary critical phenomena: expanding the critical point.

<< A prototypical model of symmetry-broken active matter -- biased quorum-sensing active particles (bQSAPs) -- is used to extend notions of dynamic critical phenomena to the paradigmatic setting of driven transport, where characteristic behaviours are nonstationary and involve persistent fluxes. >>

<< To do so, (AA) construct an effective field theory with a single order-parameter -- a nonstationary analogue of active Model B -- that reflects the fact that different properties of bQSAPs can only be interpreted in terms of passive thermodynamics in appropriately chosen inertial frames. This codifies the movement of phase boundaries due to nonequilibrium fluxes between coexisting bulk phases in terms of a difference in effective chemical potentials and therefore an 'unequal' tangent construction on a bulk free energy density. >>

<< The result is both an anomalous form of coarsening and, more generally, an exotic phase structure; binodals are permitted to cross spinodal lines so that criticality is no longer constrained to a single point. >>

<< Instead, criticality, with exponents that are seemingly unchanged from symmetric QSAPs, is shown to exist along a line that marks the entry to an otherwise forbidden region of phase space. The interior of this region is not critical in the conventional sense, but retains certain features of criticality, which (AA) term pseudo-critical. >>

<< Whilst an inability to satisfy a Ginzburg criterion implies that fluctuations remain relevant at macroscopic scales, finite-wavenumber fluctuations grow at finite rates and exhibit non-trivial dispersion relations. The interplay between the growth of fluctuations and the speed at which they move relative to the bulk results in distinct regimes of micro- and meso-phase separation. >>

Richard E. Spinney, Richard G. Morris. Nonstationary critical phenomena: expanding the critical point. Phys. Rev. E 111, 064129. Jun 23, 2025.

https://journals.aps.org/pre/abstract/10.1103/hx6n-9qsk

arXiv: 2412.15627v2 [cond-mat.stat-mech]. Jun 25, 2025. 

https://arxiv.org/abs/2412.15627

Also: particle, disorder & fluctuations, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, active particles, disorder & fluctuations, criticality, pseudo-criticality, transitions.

# gst: collective behavior based on topological vision.

<< The collective dynamics of active particles with topological vision are investigated. The topological vision, defined as a combination of the visual field and topological neighborhoods, breaks the action-reaction symmetry, thereby indicating that active particles exhibit the nonreciprocal topological interactions. >>

<< Furthermore, (AA) model considers position-based attractive force, wherein moving particles navigate using instantaneous visual information from neighboring particles within the topological vision, distinct from conventional models based on the velocity-velocity alignment. (They) demonstrate that the competition between the noise and the nonreciprocal topological interactions results in the emergence of four typical phases: gas phase, ordered phase, nematic bands, and aggregate traveling polar band. >>

<< Moreover, the nonreciprocal topological interactions impact both anomalous diffusion and ergodicity breaking. Specifically, the weak nonreciprocal topological interactions lead to ergodic subdiffusion, while the strong nonreciprocal topological interactions give rise to nonergodic superdiffusion. These findings provide a theoretical basis for understanding the nonequilibrium collective transport of active particles with topological vision. >>

Hongda Shi, Luchun Du, Wei Guo. Collective behavior based on topological vision. Phys. Rev. Research 7, 023234. Jun 6, 2025. 

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.7.023234

Also: particle, noise, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, active 

particles, noise, topological vision, 

reciprocal- nonreciprocal topological interactions, gas phase, ordered phase, nematic bands, aggregate traveling polar band.

# gst: symmetry breaking in time-dependent billiards.

AA << investigate symmetry breaking in a time-dependent billiard that undergoes a continuous phase transition when dissipation is introduced. The system presents unlimited velocity, and thus energy growth for the conservative dynamics. When inelastic collisions are introduced between the particle and the boundary, the velocity reaches a plateau after the crossover iteration. The system presents the expected behavior for this type of transition, including scale invariance, critical exponents related by scaling laws, and an order parameter approaching zero in the crossover iteration. >>

AA << analyze the velocity spectrum and its averages for dissipative and conservative dynamics. The transition point in velocity behavior caused by the physical limit of the boundary velocity and by the introduced dissipation coincides with the crossover interaction obtained from the Vrms (root mean sq V) curves. Additionally, (they) examine the velocity distributions, which lose their symmetry once the particle's velocity approaches the lower limit imposed by the boundary's motion and the system's control parameters. This distribution is also characterized analytically by an expression P(V,n), which attains a stationary state, with a well-defined upper bound, only in the dissipative case. >>

Anne Kétri Pasquinelli da Fonseca, Edson Denis Leonel. Symmetry breaking in time-dependent billiards. arXiv: 2505.20488v1 [nlin.CD]. May 26, 2025.

https://arxiv.org/abs/2505.20488

Also: billiard, transition, dissipation,  in https://www.inkgmr.net/kwrds.html 

Keywords: gst, billiard, particles, transitions, dissipation, symmetry breaking, inelastic collisions.

# gst: overcoming overly simplistic representations, chaos and regularity in an anisotropic soft squircle billiard.

<< A hard-wall billiard is a mathematical model describing the confinement of a free particle that collides specularly and instantaneously with boundaries and discontinuities. >>

<< Soft billiards are a generalization that includes a smooth boundary whose dynamics are governed by Hamiltonian equations and overcome overly simplistic representations. >>

AA << study the dynamical features of an anisotropic soft-wall squircle billiard. This curve is a geometric figure that seamlessly blends the angularity of a square with the smooth curves of a circle. (AA) characterize the billiard's emerging trajectories, exhibiting the onset of chaos and its alternation with regularity in the parameter space. (They) characterize the transition to chaos and the stabilization of the dynamics by revealing the nonlinearity of the parameters (squarness, ellipticity, and hardness) via the computation of Poincaré surfaces of section and the Lyapunov exponent across the parameter space. >>

AA << expect (Their) work to introduce a valuable tool to increase understanding of the onset of chaos in soft billiards. >>

A. González-Andrade, H. N. Núñez-Yépez, M. A. Bastarrachea-Magnani. Chaos and Regularity in an Anisotropic Soft Squircle Billiard. arXiv: 2504.20270v1 [nlin.CD]. Apr 28, 2025.

https://arxiv.org/abs/2504.20270

Also: billiard, chaos, particle, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, billiard, soft billiard, soft-wall squircle billiard, particles, smooth boundary,  specular collisions, transitions, chaos

# gst: apropos of migrations, asymmetric simple exclusion process with concerted hopping.

<< An important mechanism enabling fast ion diffusion in solid electrolytes is considered to be the significant lowering of the activation barrier when two or more ion particles hop simultaneously between sites, i.e., concerted migration, compared to single-ion hopping. >>

In this study AA << incorporate a mechanism of simultaneous particle hopping into the asymmetric simple exclusion process, which is an archetypal model for many-particle transportation phenomena, and investigate its impact on particle transport properties. >>

In Their model, << reflecting ion dynamics, the hopping rates are controlled by the activation energy, inverse temperature, and strength of an external driving field. (AA) first construct an exact solution that describes the steady state of the proposed model. By using this solution, (They) find that concerted migration substantially increases the particle current and induces a shift of the peak in the fundamental diagram, i.e., the density-current relationship. >>

AA << also show the presence of a critical temperature that maximizes the current. Additionally, we discuss the implications within parameter regions corresponding to actual materials. >>

Takahiro Ezaki, Kai Kihara, et al. Asymmetric simple exclusion process with concerted hopping. Phys. Rev. Research 7, 023068. Apr 21, 2025.

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.7.023068

Also: particle, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, migration, asymmetric exclusion process, hopping, hopping rates

# gst: switching from active Brownian motion to stationary rotation of Janus particles in a viscoelastic fluid.

<< Swimming micro-objects exist in viscoelastic fluids. Elucidating the effect of viscoelasticity on the motion of these objects is important for understanding their behavior. >>

AA << examined the motion of Janus particles self-propelled by induced charge electrophoresis over a wide range of speeds in semidilute polymer solutions. In (Their) system, the motion of Janus particles changed from active Brownian motion to stationary rotation as the speed increased. The torque for stationary rotation originates from the difference between the direction of self-propulsion and that of the time-delayed restoring force from the polymer solution, which has been reported in another self-propelled particle system. The switch from active Brownian motion to stationary rotation at different polymer concentrations can be explained by the Weisenberg number, which is defined as the ratio of the relaxation time of the polymer network to the travel time of the Janus particle to its size. >>

Keita Saito, Ryunosuke Kawano, et al. Self-propelled motion of induced-charge electrophoretic Janus particles in viscoelastic fluids. Phys. Rev. E 111, 045409. Apr 10, 2025.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.045409

️

Also: Janus, transition, particle, in FonT:

Janus https://flashontrack.blogspot.com/search?q=janus 

transition https://flashontrack.blogspot.com/search?q=transition 

particle https://flashontrack.blogspot.com/search?q=particle

Keywords: gst, Janus, transitions, particles, self-propelled particles

# gst: First-passage-time statistics of active Brownian particles: a perturbative approach.

AA << study the first-passage-time (FPT) properties of active Brownian particles to reach an absorbing wall in two dimensions. Employing a perturbation approach (They) obtain exact analytical predictions for the survival and FPT distributions for small Péclet numbers, measuring the importance of self-propulsion relative to diffusion. >>

<< While randomly oriented active agents reach the wall faster than their passive counterpart, their initial orientation plays a crucial role in the FPT statistics. Using the median as a metric, (AA) quantify this anisotropy and find that it becomes more pronounced at distances where persistent active motion starts to dominate diffusion. >>️

Yanis Baouche, Magali Le Goff, et al. First-passage-time statistics of active Brownian particles: a perturbative approach. arXiv: 2503.05401v1 [cond-mat.soft]. Mar 7, 2025.

https://arxiv.org/abs/2503.05401

Also: particle, random, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, active particles, perturbation approach, randomness, stochasticity, stochastic resetting, rotational diffusion, anisotropy

# gst: emergent flocking in mixtures of antialigning self-propelled particles.

FIG. 4. (c) Mean field phase diagram with disorder (green triangles), polarized moving bands (blue circles), and polarized patches (orange squares).

AA << observe a flocking mechanism, the emergence of a state with global polar order, in mixed systems of self-propelled particles with purely antialigning interactions, i.e., the ground state for any pair of particles is to be opposedly oriented. In binary mixtures, (They) find that flocking can be realized by cross-species antialigning that is dominant compared to intraspecies antialignment. >>

<< While the key mechanism can be understood within a mean-field description, beyond mean-field (AA) develop an asymptotically exact Boltzmann-scattering theory from first principles.  This theory yields analytical predictions for the flocking transition and shows excellent quantitative agreement with simulations of dilute systems. For large systems, (They) find either microphase separation or static patterns with patches or stripes that carry different polarization orientations. >>️

Rüdiger Kürsten, Jakob Mihatsch, Thomas Ihle. Emergent flocking in mixtures of antialigning self-propelled particles. Phys. Rev. E 111, L023402. Feb 21, 2025.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.L023402

Also: particle, flock, flocking, swarm, order, disorder, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, self-propelled particles, flock, flocking, swarm, order, disorder, transitions

# gst: attraction-enhanced emergence of friction (in colloidal matter)

<< How frictional effects emerge at the microscopic level in particulate materials remains a challenging question, particularly in systems subject to thermal fluctuations due to the transient nature of interparticle contacts. >>

Here, AA << directly relate particle-level frictional arrest to local coordination in an attractive colloidal model system. (They) reveal that the orientational dynamics of particles slows down exponentially with increasing coordination number due to the emergence of frictional interactions, the strength of which can be tuned simply by varying the attraction strength. Using a simple computer simulation model, (they) uncover how the interparticle interactions govern the formation of frictional contacts between particles. >>

AA << results establish quantitative relations between friction, coordination, and interparticle interactions. This is a key step toward using interparticle friction to tune the mechanical properties of particulate materials. >>️

<< Importantly, almost all theoretical and simulation studies on such systems do not account for interparticle friction. Incorporating frictional constraints to rolling and sliding between particles will likely have a pronounced effect on a variety of phenomena studied in attractive colloidal matter such as gel formation, coarsening and failure. >>

️

Berend van der Meer, Taiki Yanagishima, Roel P. A. Dullens. Attraction-Enhanced Emergence of Friction in Colloidal Matter. Phys. Rev. Lett. 134, 078202. Feb 21, 2025. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.078202

Also: particle, colloids, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, colloids, friction, coordination,  interparticle friction, interparticle interactions