# gst: apropos of breaking mechanisms, crack of a floating particle raft caused by waves.

<< When particles of a few tens of microns are spread on the surface of water, they aggregate under the action of capillary forces and form a thin floating membrane, a particle raft. >>

<< For a sufficiently strong wave amplitude, the raft breaks up progressively by developing cracks and producing fragments whose sizes decrease on a timescale long compared to the period of the wave. (AA)  characterize the breaking mechanisms.  >>️️

<< The visual appearance of the fragments distributed in size and surrounded by open water bears a notable resemblance to the floes produced by the fracturing of sea ice by waves in the polar oceans. Fragmentation concepts and morphological tools built for sea ice floes can be applied to (AA) macroscopic analog, on which the entire dynamic evolution is accessible. However, the mechanics of the two systems differ, as (AA) particle raft breaks due to the viscous stresses, whereas the sea ice fractures due to its bending by the waves. >>️

Louis Saddier, Ambre Palotai, et al. Breaking of a floating particle raft by water waves. Phys. Rev. Fluids 9, 094302. Sep 27, 2024.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.094302 

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

Also: 'break' in  https://flashontrack.blogspot.com/search?q=break

Also: 'raft' in  https://flashontrack.blogspot.com/search?q=raft

Also: 'zattera' (quasi-stochastic poetry) in  https://inkpi.blogspot.com/search?q=zattera  'randa' (quasi-stochastic poetry) in https://inkpi.blogspot.com/search?q=randa

Keywords: gst, crack, break, particle, raft, particle raft

# gst: multiple external fields can modulate confined active particles

AA << analyze a dilute suspension of active particles confined between walls and subjected to fields that can modulate particle speed as well as orientation. Generally, the particle distribution is different in the bulk compared to near the walls. In the bulk, particles tend to accumulate in the regions of low speed, but in the presence of an orienting field, particles rotate to align with the field and accumulate downstream in the field direction. At the walls, particles tend to accumulate pointing into the walls and thereby exert pressure on walls. But the presence of strong orienting fields can cause the particles to reorient away from the walls >>

<< The pressure at the walls depends on the wall separation and the field strengths. This work demonstrates how multiple fields with different functionalities can be used to control active matter under confinement. >>️

Vaseem A. Shaik, Zhiwei Peng, et al. Confined active matter in external fields. arXiv:2208.09797v1 [cond-mat.soft]. Aug 21, 2022. https://arxiv.org/abs/2208.09797 

Also

keyword 'particle' | 'quasiparticle' in FonT

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

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

keyword 'particelle' in Notes

(quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=particelle

Keywords: gst, particle, particle control

# gst: diffusion of active particles driven by odd interactions.

<< Odd systems do not conserve energy, violate time-reversal symmetry, and remain far from equilibrium. How odd interactions between particles affect their diffusion remains unknown. >>

<< To investigate this issue, (AA) studied the diffusion and glass transition of a two-dimensional Kob-Andersen mixture, where Brownian particles interact via the Lennard-Jones potential and nonconservative odd forces. (Their) findings indicate a significant influence of odd interactions on the system's diffusion dynamics. Odd interactions always promote diffusion. These interactions lead to a nonmonotonic relationship between the effective diffusion coefficient and particle number density. >>

<< Specifically, in systems with low oddness, the diffusion coefficient decreases steadily with increasing particle number density. Conversely, in systems with moderate oddness, an optimal particle number density exists that maximizes the diffusion coefficient. For systems with high oddness, (AA) observe two distinct peaks in the diffusion coefficient-particle number density relationship. >>

<< Furthermore, (AA) investigation into the glass transition under dense conditions reveals that adjusting the oddness at low temperatures can induce a transition from a glassy state to a liquid state. >>

Rui-xue Guo, Jia-jian Li, Bao-quan Ai.

Diffusion of active particles driven by odd interactions. Phys. Rev. E 111, 014105. Jan 3, 2025.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.014105

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

Keywords: gst, particles, diffusion, 

active brownian particles, oddness, odd interactions

# 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: 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: underdamped and overdamped scenarios of a one-dimensional inertial run-and-tumble particle

AA << study the nonequilibrium stationary state of a one-dimensional inertial run-and-tumble particle  trapped in a harmonic potential. (AA) find that the presence of inertia leads to two distinct dynamical scenarios, namely, overdamped and underdamped, characterized by the relative strength of the viscous and the trap timescales. >>

️

<< in the underdamped regime, both the position and velocity undergo transitions from a novel multipeaked structure in the strongly active limit to a single-peaked Gaussian-like distribution in the passive limit. On the other hand, in the overdamped scenario, the position distribution shows a transition from a U shape to a dome shape, as activity is decreased. Interestingly, the velocity distribution in the overdamped scenario shows two transitions—from a single-peaked shape with an algebraic divergence at the origin in the strongly active regime to a double-peaked one in the moderately active regime to a dome-shaped one in the passive regime. >>️

Debraj Dutta, Anupam Kundu, et al. Harmonically trapped inertial run-and-tumble particle in one dimension. Phys. Rev. E 110, 044107. Oct 4, 2024. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.044107

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

Keywords: gst, particle, transition 

# gst: homology for structural characterization in disordered systems

<< Local and global structural characterizations emphasize different aspects of materials, with the former focusing on microscopic features like coordination environment, short-range order, bond angles and lengths, and the latter on macroscopic features like long-range order, phase structure, lattice constants, and overall symmetry. In conclusion, local characterization focuses on the environment and structure of individual particles or regions, while global characterization refers to the overall topology or geometry of the material. >>

AA << propose a unified framework based on persistent homology to characterize both local and global structures in disordered systems. It can simultaneously generate local and global descriptors using the same algorithm and data structure, and has been shown to be highly effective and interpretable in predicting particle rearrangements and classifying global phases. >>

AA also << define a nonparametric metric, the separation index, (that) establishes a connection between particle environments and the global phase structure. >>

An Wang, Li Zou. Persistent homology for structural characterization in disordered systems. Phys. Rev. E 111, 045306. Apr 17, 2025.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.045306

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

Keywords: gst, particle, disorder, homology

# gst: soft and stiff modes in colloidal particle networks

<< Floppy microscale spring networks are widely studied in theory and simulations, but no well-controlled experimental system currently exists. >> 

AA << show that square lattices consisting of colloid-supported lipid bilayers functionalized with DNA linkers act as microscale floppy spring networks. (AA) extract their normal modes by inverting the particle displacement correlation matrix, showing the emergence of a spectrum of soft modes with low effective stiffness in addition to stiff modes that derive from linker interactions. >>

<< Evaluation of the softest mode, a uniform shear mode, reveals that shear stiffness decreases with lattice size. >>

 AA << results reveal the importance of entropic steric effects. >>

️

Julio Melio, Silke E. Henkes, Daniela J. Kraft. Soft and Stiff Normal Modes in Floppy Colloidal Square Lattices. Phys. Rev. Lett. 132, 078202. Feb 14, 2024. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.078202

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

Keywords: gst, particle, nano, colloids, network, colloidal network

# gst: stochastic surfing turbulent vorticity.

<< The chaotic dynamics of small-scale vorticity plays a key role in understanding and controlling turbulence, with direct implications for energy transfer, mixing, and coherent structure evolution. >>

Here AA << use a combination of experiments, theory and simulations to show that small magnetic particles of different densities, exploring flow regions of distinct vorticity statistics, can act as effective probes for measuring and forcing turbulence at its smallest scale. The interplay between the magnetic torque, from an externally controllable magnetic field, and hydrodynamic stresses, from small-scale turbulent vorticity, reveals an extremely rich phenomenology. >>

Notably, AA << present the first observation of stochastic resonance for particles in turbulence: turbulent fluctuations, effectively acting as noise, counterintuitively enhance the particle rotational response to external forcing. (They) identify a pronounced resonant peak in particle rotational phase-lag when the applied magnetic field matches the characteristic intensity of small-scale vortices. >>

<< Furthermore, (They) uncover a novel symmetry-breaking mechanism: an oscillating magnetic field with zero-mean angular velocity remarkably induces net particle rotation in turbulence with zero-mean vorticity, as turbulent fluctuations aid the particle in "surfing" the magnetic field. >>

Ziqi Wang, Xander M. de Wit, et al. Stochastic surfing turbulent vorticity. arXiv: 2504.08346v1 [physics.flu-dyn]. Apr 11, 2025. 

https://arxiv.org/abs/2504.08346

Also: vortex, turbulence, noise, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, vortices, turbulence, turbulent fluctuations, small-scale turbulent vorticity, stochastic resonance, noise, transitions 

# gst: solitary wave billiards

<<  In the present work (AA) introduce the concept of solitary wave billiards. I.e., instead of a point particle, (they) consider a solitary wave in an enclosed region and explore its collision with the boundaries and the resulting trajectories in cases which for particle billiards are known to be integrable and for cases that are known to be chaotic. A principal conclusion is that solitary wave billiards are generically found to be chaotic even in cases where the classical particle billiards are integrable. However, the degree of resulting chaoticity depends on the particle speed and on the properties of the potential. >>

J. Cuevas-Maraver, P.G. Kevrekidis, H. Zhang. Solitary wave billiards. arXiv: 2203.09489v1 [nlin.PS]. Mar 17, 2022. 

https://arxiv.org/abs/2203.09489

Also 

keyword 'chaos' | 'chaotic' in Font

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

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

keyword 'caos' | 'caotico' in Notes (quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=caos

https://inkpi.blogspot.com/search?q=caotico

keyword | 'soliton' in FonT

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

keywords: gst, waves, solitons, billiard, chaos 

# phys: apropos of transitions, even a tiny wobble may reshape theoretical views of the universe

<< The long-awaited first results from the Muon g-2 experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory show fundamental particles called muons behaving in a way that is not predicted by scientists’ best theory, the Standard Model of particle physics. >>️

<< Like electrons, muons act as if they have a tiny internal magnet. In a strong magnetic field, the direction of the muon’s magnet precesses, or wobbles, much like the axis of a spinning top or gyroscope. The strength of the internal magnet determines the rate that the muon precesses in an external magnetic field and is described by a number that physicists call the g-factor. This number can be calculated with ultra-high precision. >>

<< The first result from the Muon g-2 experiment at Fermilab confirms the result from the experiment performed at Brookhaven National Lab two decades ago. Together, the two results show strong evidence that muons diverge from the Standard Model prediction. >>

<< The accepted theoretical values for the muon are:

g-factor: 2.00233183620(86)

anomalous magnetic moment: 0.00116591810(43)

[uncertainty in parentheses]

The new experimental world-average results announced by the Muon g-2 collaboration today are:

g-factor: 2.00233184122(82)

anomalous magnetic moment: 0.00116592061(41)

The combined results from Fermilab and Brookhaven show a difference with theory at a significance of 4.2 sigma, a little shy of the 5 sigma (or standard deviations) that scientists require to claim a discovery but still compelling evidence of new physics. The chance that the results are a statistical fluctuation is about 1 in 40,000. >>️

We’re thrilled to announce that the first results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics! #gminus2

https://t.co/tUx4ojzIps https://t.co/t1ufui2Mwu   

17:01  Apr 7,  2021

https://twitter.com/Fermilab/status/1379811596755681286

Tracy Marc. First results from Fermilab’s Muon g-2 experiment strengthen evidence of new physics. Apr 7, 2021.

https://news.fnal.gov/2021/04/first-results-from-fermilabs-muon-g-2-experiment-strengthen-evidence-of-new-physics

Also

Themis Bowcock, Mark Lancaster. How we found hints of new particles or forces of nature – and why it could change physics. Apr 8, 2021.

 

https://theconversation.com/how-we-found-hints-of-new-particles-or-forces-of-nature-and-why-it-could-change-physics-158564

B. Abi et al. (Muon g−2  Collaboration)

 Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm. Phys. Rev. Lett. 126, 141801. Apr 7, 2021.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.141801

A primer in particle physics:

Jonathan Carroll. Explainer: Standard Model of Particle Physics. Aug 25, 2011.

https://theconversation.com/explainer-standard-model-of-particle-physics-2539

a 'cartouche' of the Standard Model 

https://images.theconversation.com/files/2516/original/sml_small.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1055&fit=crop&dpr=3

# gst: multiparticle dispersion in rotating-stratified turbulent flows (when stratification increases turbulent fluctuations may not be weaker)

AA << study the relative movement of groups of two (pairs) and four (tetrahedra) Lagrangian particles using direct numerical simulations of the stably stratified Boussinsesq equations, with Brunt-Väisälä frequency 𝑁 and Coriolis parameter 𝑓. >>

<< In all cases considered, (AA) demonstrate that the relative particle motion differs depending on whether dispersion is considered forward or backward in time, although the asymmetry becomes less pronounced when stratification and rotation increase. On the other hand, the strong fluctuations in the dispersion between two particles become more extreme when 𝑁 and 𝑓  increase. (They) also find evidence for the formation of shear layers, which become more pronounced as 𝑁 and 𝑓  become larger. Finally, (They) show that the irreversibility on the dispersion of a set of particles initially forming a regular tetrahedron becomes weaker when the influence of stratification and rotation increases, a property that (They) relate to that of the perceived rate-of-strain tensor. >>️

<< Unexpectedly, (AA) observe that the higher moments of particle separation, in particular the normalized fourth-order central moment of the separation (the kurtosis Kr) is an increasing function of stratification and rotation. This is surprising, as when stratification increases the turbulent fluctuations are expected to be weaker, (..) >>️

Sebastian Gallon, Fabio Feraco, et al. Multiparticle dispersion in rotating-stratified turbulent flows. Phys. Rev. Fluids 10, 034605. Mar 17, 2025. 

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.10.034605

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

Keywords: gst, particle, turbulence, disorder, fluctuations

# gst: apropos of inertial particles, they dispersion in turbulent canopy flows with buoyant and nonbuoyant plumes.

<< In an idealized “wind-driven” model system, (AA) consider the impact of plume buoyancy, plume momentum, and canopy turbulence on the downstream transport of particles in the wake of a canopy, and in particular the mean and standard deviation of the distribution of landing sites. >>

<< In a first set of experiments, particles were released with a fixed starting elevation above the plumes' upper boundaries, such that the particles were not lofted by the plume. In these cases, observations suggest that plumes have a role in extending particles' streamwise transport by delaying their downward transport. The plumes also have a strong role in increasing absolute dispersion of the particles, although less so when dispersion is normalized by distance traveled. While canopy turbulence alone significantly increases particle dispersion, in the presence of the plume its impact is more limited. Canopy turbulence was also found to cause shorter mean landing positions. >>

<< In a second set of experiments, particles were released at the plume source/outlet such that their initial vertical momentum was provided by the plume's momentum and buoyancy. In these cases, the impact of canopy turbulence on particle transport is observed more distinctly. The canopy coherent structures introduce a mechanical instability to the plume, which manifests as vertical oscillatory motions that lead to variability in the particles' initial conditions and, therefore, trajectories. This leads to particles settling at both shorter and longer downstream distances. >>

Hayoon Chung, Laura K. C. Sunberg, et al. Dispersion of inertial particles in turbulent canopy flows with buoyant and nonbuoyant plumes. Phys. Rev. Fluids 9, 093801. Sept 25, 2024.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.093801  

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

Keywords: gst, particle, turbulence

# gst: emergent organization and polarization due to active fluctuations.

AA << introduce and study a model of active Brownian motion with multiplicative noise describing fluctuations in the self-propulsion or activity. (They) find that the standard picture of density accumulation in slow regions is qualitatively modified by active fluctuations, as stationary density profiles are generally not determined only by the mean self-propulsion speed landscape. As a result, activity gradients generically correlate the particle self-propulsion speed and orientation, leading to emergent polarization at interfaces pointing either towards dense or dilute regions depending on the amount of noise in the system.  >>

️

Benoit Mahault, Prakhar Godara, Ramin Golestanian. Emergent organization and polarization due to active fluctuations. Phys. Rev. Research 5, L022012. April 12, 2023. 

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.5.L022012

Also: 'particle', 'fluctuations', 'noise', 'self-assembly' in https://www.inkgmr.net/kwrds.html

Keywords: gst, particle, organization, polarization, fluctuations, noise, self-propulsion, self-assembly 

# gst: apropos of evaporation, puncturing of active drops

<< By virtue of self-propulsion, active particles impart intricate stresses to the background fluids. (..) this active stress can be utilized to greatly control evaporation dynamics of active drops. >>

AA << discover a new phenomenon of puncturing of the active drops, where the air-liquid interface of the drop undergoes spontaneous tearing and there occurs a formation of a new three-phase contact line due to the liquid-air interface hitting the liquid-solid interface through evaporation-driven mass loss. Post puncturing, (AA) see an inside-out evaporation of the drop, where the new contact line sweeps towards the pinned outer contact line of the drops, contrasting regular drops that straightaway shrink to zero volume with self-similar shape. >>

<< Furthermore, (..) the activity inside the drops can manipulate the three-phase contact-line dynamics, which for contractile drops can result in an up to 50% enhanced lifetime of the drop and 33% quicker evaporation for extensile drops. By analyzing the flux distribution inside the drop, (AA) gain insights on nonintuitive deposition patterns (e.g., ring galaxy type deposits that demonstrate controllable spatial gradients in the concentrations of the deposited particles) of active particles, which are oftentimes biological substances or bimetallic nanoparticles of interest. >>

Ghansham Rajendrasingh Chandel, Vishal Sankar Sivasankar, Siddhartha Das. Evaporation of active drops: Puncturing drops and particle deposits of ring galaxy patterns. Phys. Rev. Fluids 9, 033603. Mar 27, 2024. 

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.033603

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

Keywords: gst, drop, particle, evaporation, transition, drop interactions, droplet, droploid

# gst: apropos of oscillations, viscous streaming around an immersed microfeature (e.g. a bubble)

<< Viscous streaming refers to the rectified, steady flows that emerge when a liquid oscillates around an immersed microfeature, typically a solid body or a bubble. The ability of such features to locally concentrate stresses produces strong inertial effects to which both fluid and immersed particles respond within short length (O(100) microns) and time (milliseconds) scales, rendering viscous streaming arguably the most efficient mechanism to exploit inertia at the microscale. >>️

(AA) << demonstrate that a multi-curvature approach in viscous streaming dramatically extends the range of accessible flow topologies. (They) show that numerically predicted, but never experimentally observed, streaming flows can be physically reproduced, computationally engineered, and in turn used to enhance particle manipulation, filtering and separation in compact, robust, tunable and inexpensive devices. >>️

Yashraj Bhosale, Giridar Vishwanathan, et al. Multi-curvature viscous streaming: flow topology and particle manipulation. arXiv: 2111.07184v1 [physics.flu-dyn]. Nov 13, 2021.

https://arxiv.org/abs/2111.07184

keywords: gst, viscosity, viscous streaming, bubble, oscillations, liquid oscillations, flanking vortex, particle manipulation 

# gst: asymptotic scaling in a one-dimensional billiard

<< The emergence of power laws that govern the large-time dynamics of a one-dimensional billiard of N point particles is analysed. In the initial state, the resting particles are placed in the positive half-line x≥0 at equal distances. Their masses alternate between two distinct values. The dynamics is initialized by giving the leftmost particle a positive velocity. >>

<< Due to elastic inter-particle collisions the whole system gradually comes into motion, filling both right and left half-lines. As shown by S. Chakraborti, et al. (2022), an inherent feature of such a billiard is the emergence of two different modes: the shock wave that propagates in x≥0 and the splash region in x<0. >>

<< Moreover, the behaviour of the relevant observables is characterized by universal asymptotic power-law dependencies. In view of the finite size of the system and of finite observation times, these dependencies only start to acquire a universal character. To analyse them, (AA) set up molecular dynamics simulations using the concept of effective scaling exponents, familiar in the theory of continuous phase transitions. (They) present results for the effective exponents that govern the large-time behaviour of the shock-wave front, the number of collisions, the energies and momentum of different modes and analyse their tendency to approach corresponding universal values. >>️

<< A characteristic feature of the billiard problem (AA) have considered (..) is the lack of a priori randomness, neither in the distribution of masses nor in the inter-particle distances. Therefore, the emergence of the hydrodynamic power-law asymptotics– pointing to the stochastic background of the underlying process– may be interpreted as a kind of self-averaging in the system.  >>️

Taras Holovatch, Yuri Kozitsky, et al. Effective and asymptotic scaling in a one-dimensional billiard problem. arXiv: 2503.20476v1 [cond-mat.stat-mech]. Mar 26, 2025.

https://arxiv.org/abs/2503.20476

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

Keywords: gst, billiard, randomness 

# gst: tracking four-way coupled particles in turbulence

<< In many natural and industrial applications, turbulent flows encompass some form of dispersed particles. Although this type of multiphase turbulent flow is omnipresent, its numerical modeling has proven to be a remarkably challenging problem. >>

AA << present an efficient method for point-based simulation of particles in turbulence that are four-way coupled. In contrast with traditional one-way coupled simulations, where only the effect of the fluid phase on the particle phase is modeled, this method additionally captures the back-reaction of the particle phase on the fluid phase, as well as the interactions between particles themselves. >>

AA << focus on the most challenging case of very light particles or bubbles, which show strong clustering in the high-vorticity regions of the fluid. >>

️

Xander M. de Wit, Rudie P. J. Kunnen, et al. Efficient point-based simulation of four-way coupled particles in turbulence at high number density. Phys. Rev. E 110, 015301. Jul 1, 2024. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.015301  

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

Keywords: gst, particles, bubbles, turbulence

# gst: emergence of self-organizing zigzag patterns among (magnetic) particles suspended in a liquid

<< When molecules or bacteria organize into a long-range pattern, researchers want to understand how the microscopic interactions lead to the macroscopic order. (AA) observed such self-organization in magnetic particles suspended in a liquid and subjected to an oscillating magnetic field. Through experiments and simulations, the team showed that the resulting zigzag pattern is explained by the fluid flow generated around the oscillating particles, not by any details of the particles or the applied field. Similar zigzag patterns have also been seen in charged colloids subjected to oscillating electric fields, so the explanation may cover a range of particle systems. The researchers also believe that understanding and controlling the effect could lead to useful applications in microfluidics devices. >>️

David Ehrenstein. Self-Organized Zigzags from Fluid Flow. Physics 16, 138. Aug 11, 2023.

https://physics.aps.org/articles/v16/138

Gaspard Junot, Marco De Corato, Pietro Tierno. Large Scale Zigzag Pattern Emerging from Circulating Active Shakers. Phys. Rev. Lett. 131, 068301. Aug 11, 2023. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.068301

Also: particle, self-assembly, chiral, behav, in: https://www.inkgmr.net/kwrds.html  

Keywords: gst, behavior, particle, self-assembly, self-organization, chiral, active shakers, squirmers, alternating chirality

# s-phys: more about retrocausality

<<  In a new paper (..) [AA] have lent new theoretical support for the argument that, if certain reasonable-sounding assumptions are made, then quantum theory must be retrocausal >>

<< retrocausality means that, when an experimenter chooses the measurement setting with which to measure a particle, that decision can influence the properties of that particle (or another particle) in the past, even before the experimenter made their choice. In other words, a decision made in the present can influence something in the past >>

<< "Speculatively, if there is retrocausality in the universe, then it might be the case that there are certain eras, perhaps near the big bang, in which there is not a definite arrow of causality. You might imagine that a signature of such an era might show up in cosmological data, such as the cosmic microwave background. However, this is very speculative, and I have no idea what signatures we might expect yet." >> Matthew S. Leifer.

<< The physicists don't have any experiments lined up to test retrocausality—but as the idea is more an interpretation of observations rather than making new observations, what's needed most may not be a test but more theoretical support >>

Lisa Zyga. Pysicists provide support for retrocausal quantum theory, in which the future influences the past. July 5,  2017.

https://m.phys.org/news/2017-07-physicists-retrocausal-quantum-theory-future.html

Matthew S. Leifer,  Matthew F. Pusey. Is a time symmetric interpretation of quantum theory possible without retrocausality?   Proc. Royal Soc. A. June  2017 Volume 473,  issue 2202 doi: 10.1098/rspa.2016.0607 Publ. Jun. 21, 2017.

http://rspa.royalsocietypublishing.org/content/473/2202/20160607

https://arxiv.org/abs/1607.07871