# gst: chimera states in wheel networks

<< ️How higher-order interactions influence dynamical behavior in networks of coupled chaotic oscillators remains an open question. To address this, (AA) investigate emergent dynamical behaviors in a wheel network of Rössler and Lorenz oscillators that incorporates both pairwise (1-simplex) and higher-order (2-simplex) interactions under three coupling schemes, namely, diffusive, conjugate, and mean-field diffusive coupling. >>

<< ️(AA) numerical analysis reveals four distinct collective behaviors: synchronization, desynchronization, chimera states, and synchronized clusters. To systematically classify these dynamical behaviors, (They) introduce two statistical measures that effectively capture synchronization patterns among arbitrarily positioned nodes. Applying these measures across all dynamical models and coupling schemes (six different models in total), (They) show that both pairwise and higher-order interactions crucially influence the emergence and robustness of chimera states. (They) observe that under pairwise interaction alone, chimera states appear with high prevalence in specific coupling ranges, though the robustness depends on both the coupling scheme and the underlying dynamical system. >>

<< Incorporation of higher-order interactions reveals that the higher-order interaction underlying diffusive coupling enhances chimera states in both Rössler and Lorenz networks; under conjugate coupling, it strengthens chimera states in Lorenz but instead promotes full synchronization in Rössler; and under mean-field diffusive coupling, higher-order interactions generally favor synchronization, particularly for Rössler oscillators, but promote chimera in the Lorenz system for the intermediate range of its strengths. >>

<< ️Overall, (AA) results demonstrate that higher-order interactions can significantly modulate, promote, or suppress chimera states depending on the coupling mechanism and oscillator dynamics. >>

Ashwathi Poolamanna, Medha Bhindwar, Chandrakala Meena. Chimera States in Wheel Networks. arXiv: 2601.01411v1 [nlin.CD]. Jan 4, 2026.

https://arxiv.org/abs/2601.01411

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

Keywords: gst, chimera, network, transitions

# gst: noise enables conditional recovery from collapse.

<< ️(AA) report a paradoxical phenomenon where stochasticity reverses deterministic collapse in threshold-activated systems. By using a hybrid logistic-sigmoidal map, (They) show that weak noise alters phase-space topology, enabling probabilistic recovery from extinction. Lyapunov and quasipotential analyses reveal noise-induced metastability and stochastic robustness absent in deterministic frameworks. These results suggest that environmental variability can stabilize nonlinear systems, offering a counternarrative to classical extinction theory. >>

Vinesh Vijayan, B. Priyadharshini, R. Sathish Kumar, G. Janaki. Noise enables conditional recovery from collapse: Probabilistic persistence in threshold-activated systems. Phys. Rev. E 112, 064212. Dec 19, 2025.

https://journals.aps.org/pre/abstract/10.1103/xgq1-nnqb

Also:  Vinesh Vijayan, et al. Noise reinstates collapsed populations; stochastic reversal of deterministic extinction. arXiv: 2507.03954v1 [q-bio.PE]. Jul 5, 2025. https://arxiv.org/abs/2507.03954   https://flashontrack.blogspot.com/2025/07/gst-noise-reinstates-collapsed.html

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

Keywords: gst, chaos, chaotic systems, noise, weakness, disorder,  fluctuations, tipping point, transitions, stochasticity, stochastic reversal, stochastic rescue. 

# gst: 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. (They) 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 (squareness, ellipticity, and hardness) via the computation of Poincaré surfaces of section and the Lyapunov exponent across the parameter space. (They) 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. Phys. Rev. E 112, 064213. Dec 22, 2025.

https://journals.aps.org/pre/abstract/10.1103/4xhm-r64f

arXiv: 2504.20270v2 [nlin.CD]. 28 Apr 2025

https://arxiv.org/abs/2504.20270

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

Keywords: gst, chaos, billiard, hard-wall billiards, soft billiards, particles, transitions.

# gst: ambiguous signals and efficient codes.

<< In many biological networks the responses of individual elements are ambiguous. (AA) consider a scenario in which many sensors respond to a shared signal, each with limited information capacity, and ask that the outputs together convey as much information as possible about an underlying relevant variable. In a low noise limit where can make analytic progress, (They) show that individually ambiguous responses optimize overall information transmission. >>

Marianne Bauer, William Bialek. Ambiguous signals and efficient codes. arXiv: 2512.23531v1 [physics.bio-ph]. Dec 29, 2025. 

https://arxiv.org/abs/2512.23531

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

Keywords: gst, networks, uncertainty, noise, ambiguity, ambiguous encodings, mixed selectivity, optimization, signal-to-noise ratio. 

#gst: intermittent motility of a synthetic active particle in changing environments.

<< ️(AA) experimentally investigate the dynamics of synthetic active particles composed of gravitationally bouncing, superwalking droplets confined within an annular fluid bath. >>

<< ️Driven by a topologically pumping dual-frequency waveform, the droplets exhibit alternating active (walking) and dormant (bouncing) phases, producing intermittent azimuthal motion. Tracking individual droplets reveals pseudolaminar chaotic dynamics in the time series of particle's angular position, characterized by laminar plateaus that are interrupted by short irregular bursts of activity. >>

<< ️Increasing the driving amplitude induces a qualitative change in the active particle's intermittent dynamics, arising from a symmetry-breaking transition in its Faraday-wave field environment: continuous SO(2)-symmetric "channelling" waves give way to discrete "trapping" patterns. >>

<< ️These findings demonstrate how environmental symmetry and spatiotemporal structure modulate motility and intermittency in synthetic active matter. >>

Rudra Sekhri, Rahil N. Valani, Tapio Simula. Intermittent Motility of a Synthetic Active Particle in Changing Environments. arXiv: 2512.16135v1 [physics.flu-dyn]. Dec 18, 2025.

https://arxiv.org/abs/2512.16135 

Also: drop, droplet, droploid, intermittency, behav, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, active matter, drops, droplets, droploids, intermittency, behavior, active walking phase, dormant bouncing phase,  trapping patterns.

# brain: abrupt over gradual learning in the differential reinforcement of response duration task.

<< ️Learning can occur in markedly different ways: in some cases, it unfolds as a gradual process, with behavior improving slowly toward an asymptotic level of performance; in others, it appears as an abrupt process that sharply separates behavior before and after a change point. Under-standing the behavioral and neural processes underlying these distinct acquisition patterns may be critical for elucidating the basic principles of learning. >>

<< ️(AA) investigated this question experimentally using naïve rats performing a differential reinforcement of response duration (DRRD) task, in which animals were required to remain inside a nosepoke for a minimum duration of 1.5 seconds to get a sugar pellet as a reward. All rats learned to wait longer in the nosepoke when comparing behavior at the beginning and at the end of the experiment. (They) tested several continuous models against a single change point (CP) model, in which behavior changes at a specific moment and remains stable thereafter. Instead of the traditional approach based on trial-segmented behavior, (AA) used the real time elapsed since the beginning of the experiment as a continuous, uncontrolled variable. (They) fitted all models to data from individual rats and compared model fit quality across alternatives. >>

<< ️(AA) results provide strong evidence in favor of an abrupt change, as captured by the CP model, over all other models. Moreover, the residuals of the CP model exhibited a Gaussian distribution, suggesting that no additional systematic dynamics remained unexplained and that the behavioral dynamics were fully captured by a single change point. >>

Mateus Gonzalez de Freitas Pinto, Alexei Magalhães Veneziani, Marcelo Bussotti Reyes. Evidence in favor of abrupt over gradual learning in the differential reinforcement of response duration (DRRD) task. bioRxiv. doi: 10.64898/ 2025.12.26.696617. Dec 27, 2025.

https://www.biorxiv.org/content/10.64898/2025.12.26.696617v1

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

Keywords: brain, behavior, cognition, learning, change point models, criticality.

# 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.