# gst: settling dynamics of an oloid, experiments and simulations.

<< ️This (AA) study presents a combined experimental and computational investigation of an oloid shaped particle settling in a quiescent fluid. The oloid, a unique convex shape with anisotropic geometry, provides a distinctive model for exploring how a particle's shape and orientation affect its settling dynamics. >>

<< ️(AA) results indicate two distinct falling modes for the oloid, separated by Galileo number. The stable mode is characterised by a preferential orientation, with a rotation around the vertical axis, whereas the tumbling mode has randomly distributed orientation and rotation statistics. (They) characterise the falling velocity, orientation, and rotation dynamics of the oloids over a range of Galileo numbers. Additionally, the influence of the initial orientation is revealed to determine the rotation dynamics at low Galileo numbers. >>

Mees M. Flapper, Giulia Piumini, Roberto Verzicco, et al. Settling dynamics of an oloid: experiments and simulations. arXiv: 2511.05137v1 [physics.flu-dyn]. Nov 7, 2025.

https://arxiv.org/abs/2511.05137

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

Keywords: gst, particle, transitions, oloids, oloid shaped particles, multiple falling regimes, falling mode, tumbling mode.

# gst: synchronization by degenerate noise.

<< ️In this paper, (AA) derive several criteria for (weak) synchronization by noise without the global swift transitivity property. (Their) sufficient conditions for (weak) synchronization are necessary and can be applied to scenarios involving degenerate or non-Gaussian noise. >>

<< ️These (AA) results partially answer the open question posed by Flandoli et al. (Probab Theory Relat Fields 168:511-556, 2017). As an application, (AA) prove that the weak attractor for stochastic Lorenz 63 systems driven by degenerate noise consists of a single random point provided the noise intensity is small, and there is no weak synchronization if the noise intensity is large. This indicates that a bifurcation occurs in relation to the intensity of the noise. >>

Xianming Liu, Xu Sun. Synchronization by degenerate noise. arXiv: 2512.18278v1 [math.DS]. Dec 20, 2025.

https://arxiv.org/abs/2512.18278

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

Keywords: gst, noise, randomness, degenerate noise, non-Gaussian noise, weak synchronization, weak attractors.

# gst: triadic instabilities of internal wave standing modes.

<< ️This (AA) article presents (their) experimental study of the nonlinear destabilization of an internal wave standing mode in a uniformly stratified fluid within a rectangular domain. (They) measure the linear response of the system and target its resonances to generate a high-amplitude standing mode, prone to instabilities. Using modal decomposition tools, (They) determine the characteristics of the secondary waves and show that they have a standing-mode spatial structure. Box resonance conditions associated with nonlinear resonance conditions lead to a significant deviation from the internal wave dispersion relation and complex nonlinear interaction dynamics. >>

<< Following previous work, (AA) develop a weakly nonlinear analysis to understand the secondary wave characteristics. This approach, validated by experimental results, shows that the secondary wave characteristics as well as the general nonlinear dynamics are highly sensitive to the domain geometry and to the forcing mode. >>

Julie Deleuze, Ilias Sibgatullin, Philippe Odier, Sylvain Joubaud. Triadic instabilities of internal wave standing modes. Phys. Rev. Fluids 10, 124803. Dec 8, 2025.

https://journals.aps.org/prfluids/abstract/10.1103/2pvv-wkc4

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

Keywords: gst, waves, instability.

# gst: compressed self-avoiding walks in two and three dimensions.

<< ️(AA) consider the phase transition induced by compressing a self-avoiding walk in a slab where the walk is attached to both walls of the slab in two and three dimensions, and the resulting phase once the polymer is compressed. The process of moving between a stretched situation where the walls pull apart to a compressed scenario is a phase transition with some similarities to that induced by pulling and pushing the end of the polymer. >>

<< ️However, there are key differences in that the compressed state is expected to behave like a lower dimensional system, which is not the case when the force pushes only on the end point of the polymer. (They) use scaling arguments to predict the exponents both associated with the phase transition and in the compressed state and find good agreement with Monte Carlo simulations. >>

C. J. Bradly, N. R. Beaton, A. L. Owczarek. Compressed self-avoiding walks in two and three dimensions. Phys. Rev. E 112, 054126. Nov 17, 2025.

https://journals.aps.org/pre/abstract/10.1103/wtrv-4g4h

arXiv: 2506.11433v2 [cond-mat.stat-mech]. Oct 23, 2025.

https://arxiv.org/abs/2506.11433

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

Keywords: gst, transitions, phase transitions, self-avoiding walk, criticality, polymer conformation, topology.

# gst: apropos of reversibility, dynamics of reversible plasticity in an amorphous solid.

<< ️Local rearrangements are the elements of plastic deformation in an amorphous solid. In oscillatory shear, they can switch reversibly between two distinct configurations. While these repeating relaxations are typically considered in the limit of slow driving, their dynamics is less well understood. >>

<< ️(AA) perform experiments on a colloidal amorphous solid at an oil-water interface. The rearrangement timescales we observe span at least 1 decade, with no apparent upper bound. As frequency is increased, individual rearrangements appear faster and more hysteretic, but may disappear entirely above a crossover frequency -- suggesting that in practical experiments, the slowest rearrangements may be latent. (They) show how to find the effective potential energy that reproduces a particle's frequency-dependent motion. In rare cases, this potential energy has only one minimum. >>

Zhicheng Wang, Nathan C. Keim. Dynamics of Reversible Plasticity in an Amorphous Solid. arXiv: 2512.17816v1 [cond-mat.soft]. Dec 19, 2025.

https://arxiv.org/abs/2512.17816

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

Keywords: gst, colloids, colloidal amorphous solids, repulsive particles, reversible plasticity, plastic rearrangements, oscillatory shear, bistable rearrangements, repeating relaxations, transitions, logarithmic aging, silly putty dynamics.

# evol: fluctuating environments favor extreme dormancy strategies and penalize intermediate ones.

<< ️Dormancy is a widespread adaptive strategy that enables populations to persist in fluctuating environments, yet how its benefits depend on the temporal structure of environmental variability remains unclear. (AA) examine how dormancy interacts with environmental correlation times using a delayed-logistic model in which dormant individuals reactivate after a fixed lag while birth rates fluctuate under temporally correlated stochasticity. >> 

<< ️Numerical simulations and analytical calculations show that the combination of demographic memory and colored multiplicative noise generates a strongly non-monotonic dependence of fitness on dormancy duration, with three distinct performance regimes. Very short dormancy maximizes linear growth but amplifies fluctuations and extinction risk. Very long dormancy buffers environmental variability, greatly increasing mean extinction times despite slower growth. Strikingly, (They) find a broad band of intermediate dormancy durations that is maladaptive, simultaneously reducing both growth and persistence due to a mismatch between delay times and environmental autocorrelation. >>

<< ️An evolutionary agent-based model confirms bistability between short- and long-dormancy strategies, which avoid intermediate lag times and evolve toward stable extremes. >>

<< ️These (AA) results show that dormancy duration is not merely a life-history parameter but an adaptive mechanism tuned to environmental timescales, and that intermediate "dangerous middle" strategies can be inherently disfavored. More broadly, this work identifies a generic mechanism by which demographic delays interacting with correlated environmental variability produce a non-monotonic fitness landscape that selects for extreme timing strategies. >>

Jorge Hidalgo, Lorenzo Fant, Rafael Rubio de Casas, Miguel A. Muñoz. Fluctuating Environments Favor Extreme Dormancy Strategies and Penalize Intermediate Ones. arXiv: 2512.05856v1 [q-bio.PE]. Dec 5, 2025.

https://arxiv.org/abs/2512.05856

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

Keywords: evolution, adaptation, transition, dormancy, fluctuating environments, stochasticity, noise.

# gst: bursting bubbles in Herschel-Bulkley fluids, dynamics and jetting transitions.

<< ️When a bubble rises to a free surface, its bursting dynamics in Newtonian fluids are governed by the interplay between viscous, capillary, and gravitational forces. In this work, (AA) extend this classical problem to Herschel-Bulkley fluids, elucidating the role of viscoplasticity and non-Newtonian rheology in bubble bursting. Using direct numerical simulations validated against experiments, (They) systematically explore the influence of the key governing dimensionless parameters, such as the Bond number, the Ohnesorge number, the shear-dependent behavior and the plastocapillary number, each varied over several orders of magnitude. >>

<< ️(AA) results reveal that viscoplasticity strongly controls the evolution and interaction of capillary waves within the cavity formed upon bubble rupture. Shear-thinning and shear-thickening effects are significant only for moderate Ohnesorge numbers, while at large Ohnesorge values the free surface dynamics converge to a non-flat equilibrium shape once the internal stresses fall below the yield stress. >>

<< ️These (AA) findings provide new insights into the coupled effects of viscosity, gravity, yield stress, and shear-dependent rheology in multiphase flows, with broad implications for natural and industrial processes involving gas-liquid interfaces. >>

A. H. Ghaemi, Z. Yang, A. Huang, et al. Bursting bubbles in Herschel-Bulkley fluids: dynamics and jetting transitions. arXiv: 2511.23345v1 [physics.flu-dyn]. Nov 28, 2025.

https://arxiv.org/abs/2511.23345

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

Keywords: gst, bubble, waves, capillary waves, bubble bursting, bubble rupture, viscosity, capillary and gravitational forces, shear-thinning and shear-thickening effects, yield stress, free surface dynamics, non-flat equilibrium.