# gst: apropos of packing regimes, understanding the dynamics of evaporation-driven colloidal self-assembly.

<< ️Complex colloidal cluster morphologies are desirable for the fabrication of advanced materials, such as photonic crystals and meta-materials, and can be formed through evaporation-driven packing. By coupling lattice Boltzmann and discrete element methods, here (AA) elucidate the rich interplay between fluid and particle dynamics during evaporation-driven self-assembly of spherical colloidal particles. >>

<< ️(They) construct a regime diagram for a wide range of evaporation rates, interparticle friction coefficients, and particle numbers, identifying parameter regimes for open, closed, and minimal moment of inertia cluster configurations. >>

<< ️Analyzing the competition between capillary, hydrodynamic, normal, and friction forces, (They) show that interparticle friction can exert a disproportionately strong influence on the final packing outcome despite being considerably smaller in magnitude than other forces at play. (Their) simulation results further highlight the potential for tuning colloidal cluster configurations via their dynamic trajectories. >>

Junyu Yang, Abhinav Naga, Xitong Zhang, et al. Understanding the Dynamics of Evaporation-Driven Colloidal Self-Assembly. arXiv: 2605.04878v1 [cond-mat.soft]. May 6, 2026.

https://arxiv.org/abs/2605.04878

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

Keywords: gst, particle, self-assembly, evaporation, spherical colloidal particles, complex colloidal clusters, evaporation-driven packing, evaporation-driven self-assembly, interparticle friction coefficients, minimal moment of inertia, tuning colloidal cluster configurations.

# gst: critical parameters of an oval billiard with an elliptical component.

<< ️(AA) explore the critical parameters responsible for the transition from integrability to chaos in a family of billiards combining elliptical and oval deformations. Unlike standard oval billiards, where a known critical parameter governs the destruction of the last invariant curve, the introduction of an integrable elliptic component yields a second deformation axis. >>

<< (They) derive an analytical expression for the critical parameter in this combined system and validate it numerically using Slater's theorem, showing that increasing the elliptical component lowers the critical threshold for global chaos. >>

<< ️Moreover, (They) uncover a previously unexplored regime: when the two deformation components are in phase, the elliptic contribution progressively suppresses chaos, leading to the restoration of invariant curves and periodic orbits. A first-order analytical approximation confirms this behavior, supported by numerical validation. >>

<< ️(Their) results reveal how the interplay between distinct boundary deformations enriches phase-space organization and offers enhanced controllability of chaotic dynamics in billiard systems. >>

Anne Kétri P. da Fonseca, Joelson D. V. Hermes, Edson D. Leonel. Critical parameters of an oval billiard with an elliptical component. arXiv: 2605.00145v1 [nlin.CD]. Apr 30, 2026. 

https://arxiv.org/abs/2605.00145

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

Keywords: gst, billiard, transition, chaos, criticality, elliptical and oval deformations. 

# gst: topological defects in spiral wave chimera states.

<< ️Chimera states, characterized by the coexistence of coherent and incoherent domains, represent a paradigm of self-organization in complex systems. In this study, (AA) introduce a topological analysis method based on winding numbers to characterize the dynamics of spiral wave chimeras in a two-dimensional phase oscillator network. >>

<< ️(Their) investigation reveals distinct scaling laws governing the system's evolution across the phase lag 𝛼. Perturbation analysis in the limit 𝛼→0 demonstrates that the incoherent core radius scales linearly with 𝛼. In contrast, within the stable chimera regime, the average total positive winding number 𝜇 follows a clear exponential growth law 𝜇=𝑎⁢𝑒^(𝑏⁢𝛼). This scaling disparity signals a physical crossover from a regime dominated by geometric core expansion to one driven by active topological excitation. >> 

<< ️Furthermore, (They) identify a statistical transition in the defect distribution from binomial-like to Poisson-like behavior at a critical threshold 𝛼*. These results demonstrate that topological defects possess intrinsic statistical order, establishing 𝜇 as a robust macrovariable for analyzing the structural complexity of chimera states. >>

Lintao Liu, Nariya Uchida. Topological defects in spiral wave chimera states. Phys. Rev. E 113, 054207. May 8, 2026.

https://journals.aps.org/pre/abstract/10.1103/yhbq-ztk8

arXiv: 2511.21058v2 [nlin.AO]. 5 Mar 2026.

https://arxiv.org/abs/2511.21058

Also: chimera, waves, self-assembly, transition, network, defect, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, chimera, waves, self-assembly, transition, network, defect, topology, spiral wave chimeras, two-dimensional phase oscillator network, active topological excitations, topological defects. 

# gst: apropos of smallest amplitude perturbations that trigger transition to turbulence, the minimal seeds in the Stokes boundary layer.

<< ️Minimal seeds, the smallest amplitude perturbations that trigger transition to turbulence, are presented in the Stokes boundary layer, the oscillating flow of a viscous fluid above a flat plate. The minimal seed trajectories are dominated by the Stokes boundary layer's large linear transient growth at early times, but only 73% of the initial energy is formed from the linearly optimal growing mode; the remainder ensures that nonlinear interaction transfers energy from spanwise- to streamwise- independent structures, and makes up for a timing mismatch between the end of linear transient growth and the production phase of the edge state (the saddle point separating laminar and turbulent basins of attraction). >>

Tom Eaves. Minimal seeds in the Stokes boundary layer. arXiv: 2604.23213v1 [physics.flu-dyn]. Apr 25, 2026.

https://arxiv.org/abs/2604.23213

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

Keywords: gst, turbulence, transitions, minimal seeds, laminar and turbulent basins of attraction.

# gst: capillary slinky; equilibrium and dynamics of a droplet in a soft spring.

<< ️Springs can be found in many applications and biological systems, and when these are soft, they easily deform. At small scales, capillarity can induce a force leading to spring deformations when the elastocapillary number is small. >>

<< ️ (AA) demonstrate through experiments the nontrivial equilibrium-shape liquid droplets adopt in these soft springs, which form an annulus, eruciform, and spherical shapes. When these droplets are set in motion, they display different flow regimes with significant dissipation generated by the internal rotational flow. >>

<< ️The static and dynamics of droplets in such a capillary slinky are also used to demonstrate how surface tension can actuate springs by stretching/compression, while providing a way for active flow control in soft springs. >>

Bidisha Bhatt, Andreas Carlson. Capillary slinky: Equilibrium and dynamics of a droplet in a soft spring. Phys. Rev. Fluids 11, 043607. Apr 29, 2026.

https://journals.aps.org/prfluids/abstract/10.1103/p9j4-hp5h

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

Keywords: gst, drops, droplets, droploids, capillarity, capillary slinky, spring deformations, annulus, eruciform, spherical shapes, rotational flows.

# gst: apropos of unsteady two-dimensional flows, the Lagrangian rotating contracting structures.

<< ️(AA) identify materially defined regions in unsteady two-dimensional flows that combine finite-time contraction with elevated accumulated intrinsic rotation along trajectories, which (They) term Lagrangian rotating contracting structures (LRCS). These regions are detected using existing objective diagnostics—the Lagrangian-averaged vorticity deviation (LAVD) together with direct tests of material contraction—without relying on the geometry of LAVD level sets. >>

<< ️In strongly deforming flows, LAVD maxima need not correspond to vortical regions or be enclosed by regular level sets, rendering geometry-based identification unreliable. Nevertheless, regions exhibiting inward spiraling motion and contraction can be extracted by combining LAVD with a contraction criterion. >>

<< ️Applications to atmospheric and oceanic flows show that such behavior arises both in twisted LAVD fields generated at submesoscales and in mesoscale flows where it is enhanced by inertial effects, with finite-time contraction providing the dynamical constraint that isolates materially organized regions with elevated intrinsic rotation. >>

F.J. Beron-Vera. Lagrangian Rotating Contracting Structures. arXiv: 2604.25036v1 [nlin.CD]. Apr 27, 2026.

https://arxiv.org/abs/2604.25036

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

Keywords: gst, vortex, instability, finite-time contraction, accumulated intrinsic rotation, Lagrangian rotating contracting 

structures, inward spiraling motion.

# gst: chaotic billiard lasers.

<< ️This chapter provides an overview of chaotic billiard lasers as a prominent branch of quantum chaos. These lasers offer an ideal experimental platform for demonstrating the principles of quantum chaos within a physical system. >>

<< ️(AA) begin by introducing the fundamental principles of chaotic ray dynamics in optical microcavities, where the transition from regular to fully chaotic dynamics fundamentally alters the underlying wavefunctions and lasing properties. A central focus is placed on "chaos-assisted light emission," which serves as a practical manifestation of "chaos-assisted tunneling" -- a hallmark phenomenon in the study of quantum chaos. >>

<< ️(They) discuss both theoretical frameworks and experimental validations, demonstrating how chaotic orbits facilitate the coupling between evanescently localized modes and far-field emission. >>

<<️ Furthermore, exploring how the presence of a gain medium influences established results from quantum chaos research remains a fundamental and intriguing problem in physics. To address this, (They) establish a rigorous and comprehensive derivation of the Maxwell-Bloch equations for two-dimensional microcavity lasers, specifically examining their application to fully chaotic, stadium-shaped billiard lasers. >>

<< ️By bridging the gap between nonlinear lasing processes and chaotic wavefunctions, this chapter highlights the unique potential of chaotic billiards for controlling light-matter interactions and shaping the next generation of unconventional coherent light sources. >>

Takahisa Harayama. Chaotic Billiard Lasers. arXiv: 2604.23614v1 [quant-ph]. 26 Apr 26, 2026.

https://arxiv.org/abs/2604.23614

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

Keywords: gst, billiard, billiard laser, waves, transitions, chaos, quantum chaos, chaotic billiard, chaos-assisted light emission, chaos-assisted tunneling. 

# gst: self-mediation of runaway electrons via self-excited wave-wave and wave-particle interactions.

<< ️Nonlinear dynamics of runaway electron induced wave instabilities can significantly modify the runaway distribution critical to tokamak operations. Here (AA) present a fully kinetic simulation of runaway-driven instabilities toward nonlinear saturation in a warm plasma where collisional damping is subdominant. >>

<< ️It is found that the slow-X modes grow an order of magnitude faster than the whistler modes, and they parametrically decay to produce whistlers much faster than those directly driven by runaways. These parent-daughter waves, as well as secondary and tertiary wave instabilities, initiate a chain of wave-particle resonances that strongly diffuse runaways to the backward direction. This reduces almost half of the current carried by high-energy runaways, over a time scale orders of magnitude faster than experimental shot duration. These results beyond quasilinear analysis may impact anisotropic energetic electrons broadly in laboratory, space, and astrophysics. >>

Qile Zhang, Yanzeng Zhang, Qi Tang, et al. Self-mediation of runaway electrons via self-excited wave-wave and wave-particle interactions. Phys. Rev. E 113, L043203. Apr 20, 2026.

https://journals.aps.org/pre/abstract/10.1103/k3bq-cvjs

arXiv: 2409.15830v2 [physics.plasm-ph]. Mar 7, 2026.

https://arxiv.org/abs/2409.15830

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

Keywords: gst, waves, whistler waves, instability, particles, collisional damping, wave-particle resonance

# brain: hippocampus can rewires itself even after a single experience.

<< ️Understanding how brains learn and remember remains among the most important challenges in science. Recent studies in the hippocampus implicate a new form of synaptic plasticity, named behavioral timescale synaptic plasticity (BTSP), in the generation of experience-based learning and memory. BTSP is a strong, bidirectional type of plasticity that affects synaptic weights over many seconds of time. It is induced by single dendritic plateau potentials, as opposed to many action potentials, and is thus capable of producing new place cells in one trial. Plateau potential initiation is controlled, at least in part, by local feedback inhibition and an instructive input from a higher-order brain region that potentially links the plasticity to current experience.  >>

<< ️The new credit assignment procedure in BTSP provides a nonstandard mechanism for memory storage and retrieval that could mitigate the need for widespread synapse stabilization. In addition, it may allow hippocampal networks both to form memories of specific behavioral episodes and to generalize on the basis of past episodes. Finally, recent BTSP investigations could provide a basis for future explorations into how brains learn and remember, ranging from the systems and cognitive levels down to the basic biochemical building blocks of learning and memory. >>

Jeffrey C. Magee. Behavioral timescale synaptic plasticity: properties, elements and functions. Nature Neurosci 29; 520–534. Feb 20, 2026.

https://www.nature.com/articles/s41593-026-02214-2

Antoine D. Madar, Aaron D. Milstein, Thomas J. O’Dell, et al. Behavioral Timescale Synaptic Plasticity: A Burst in the Field of Learning and Memory. J. Neurosci .45 (46) e1332252025. Nov 12,  2025.

https://www.jneurosci.org/content/45/46/e1332252025

Yasemin Saplakoglu. A New Type of Neuroplasticity Rewires the Brain After a Single Experience. quantamagazine.org. Apr 24, 2026.

https://www.quantamagazine.org/a-new-type-of-neuroplasticity-rewires-the-brain-after-a-single-experience-20260424/

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

Keywords: brain, dance,  hippocampus, synaptic plasticity, behavioral timescale synaptic plasticity (BTSP), learning, memory, single dendritic plateau potentials, local feedback inhibition.

# gst: twin satellites and ring bubbles from coalescing magnetically levitated air bubbles in water.

<< ️(AA) investigate the ejection of satellite bubbles during the coalescence of two air bubbles in water. Using magnetic levitation (They) suspend the bubbles, with diameters in the range 3–15 mm, in a stable, neutrally buoyant state, free from mechanical constraints. >>

<< ️(Their) experiments reveal the simultaneous ejection of twin satellite bubbles from the poles of the bubble formed from the coalescence of equal-sized precursors. More generally, (They) find that the number and size of the ejected satellites are dependent on the initial size ratio of the precursor bubble pair. Numerical simulations, which agree well with (Their) experiments, show that satellite production is governed by the combined effect of two distinct processes: the arrival of a capillary wave crest at a pole and the rapid retraction of that polar region. >>

<< ️(They) propose a timing model that successfully predicts the range of size ratios for which single, double, or no satellites are formed. (Their) analysis also offers insight into the absence of satellite ejection in similarly sized liquid drop coalescence. Furthermore, (They) report the experimental observation of toroidal bubble ejection from precursor bubbles with approximately 2:1 diameter ratios, and (They) show that the formation of these toroidal bubbles is also governed by (Their) timing model. >>

N. Sampara, G. Hunter-Brown, K. A. Baldwin, et al. Twin satellites and ring bubbles from coalescing magnetically levitated air bubbles in water. Phys. Rev. Fluids 11, 043605. Apr 22, 2026.

https://journals.aps.org/prfluids/abstract/10.1103/fr1q-m1j9

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

Keywords: gst, waves, capillary wave crest, drops, bubbles, twin satellite bubbles, toroidal bubbles, drop coalescence, satellite ejection.

# gst: transient chaos and Rayleigh particle escape out of a time modulated optical trap.

<< ️(AA) consider Rayleigh particles in a periodically modulated optical trap formed by two counterpropagating Gaussian beams. It is shown that for certain values of the parameters the system exhibits transient chaos which manifests itself in particle acceleration and subsequent directional ejection out of the trap. The escape flights are terminated at a distance of hundreds of wavelengths from the trap center and the particles return to the trap under the action of the Stokes force. The particle escape is shown to be a threshold effect that can be potentially employed for particle sorting. >>

Evgeny N. Bulgakov, Konstantin N. Pichugin, Dmitrii N. Maksimov. Transient chaos and Rayleigh particle escape out of a time modulated optical trap. Phys. Rev. E 113, 044216. Apr 23, 2026.

https://journals.aps.org/pre/abstract/10.1103/fj7q-vm5b

arXiv:2512.03403v1 [nlin.CD]. Dec 3, 2025.

https://arxiv.org/abs/2512.03403

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

Keywords: gst, chaos, transitions, particle, escape, periodically modulated trap, threshold effect.

# gst: chaotic ghosts in systems with parameter drift; delay and control critical transitions.

<< ️In dynamical systems with a time-dependent parameter, i.e., parameter drift, after crossing a saddle-node bifurcation, the so-called ghost state formed by the disappeared equilibria or periodic orbit can influence transient dynamics, causing a delayed transition. >>

<< ️This phenomenon has been investigated previously. However, the effect of chaotic ghosts on the critical transition in drifting systems has been less studied. In this paper, (AA) explore how chaotic ghosts and drifting rates influence critical transitions from the perspective of the ensemble. >> 

<< ️The (AA) results reveal the mechanism of the delayed transition related to chaos and how trajectories on the initial ensemble composed of a chaotic attractor transition to a qualitatively different object during the drift. In addition, (They) quantify the delayed transition and further find that the delay follows a power-law scaling with respect to the drifting rate. Finally, (AA) show that the critical transition is fully avoided as long as the reversal rate of the parameter exceeds a certain critical rate, even though the bifurcation point has been crossed. >>

Han Su, Denghui Li, Jicheng Duan, et al. Chaotic ghosts in systems with parameter drift: Delay and control critical transitions. Phys. Rev. E 113, 044207. April 13, 2026.

https://journals.aps.org/pre/abstract/10.1103/bdf8-wkpm

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

Keywords: gst, chaos, attractor, transitions, chaotic attractor transition, chaotic ghosts, criticality, critical transitions, bifurcation point, saddle-node bifurcation, ghost state, transient dynamics, delay, delayed transition, drifting rate.

# gst: quantum kicked top; a paradigmatic model

<< ️The quantum kicked top (QKT) is one of the most widely studied models in quantum chaos, providing a minimal yet powerful framework for exploring the relationship between classical nonlinear dynamics and quantum behavior. Unlike many chaotic systems with infinite-dimensional Hilbert spaces, the QKT possesses a finite-dimensional Hilbert space, making it analytically and numerically controllable while still showing a rich dynamical phenomena. >>

<< ️(AA) present a comprehensive introduction to the QKT as a paradigmatic model of quantum chaos. Starting from the classical kicked top, (They) derive the discrete nonlinear map governing the dynamics on the unit sphere and analyze its phase space structure through fixed points, stability analysis, bifurcations and Lyapunov exponents. (They) then discuss the role of symmetries, including rotational and time-reversal symmetry, and how their breaking modifies the dynamics. >>

<< ️By linking classical phase space structures with quantum dynamical indicators, the QKT provides a clear setting to investigate the emergence of chaotic behavior in the semiclassical limit. The chapter, therefore, highlights the quantum kicked top as a bridge between nonlinear classical dynamics, quantum chaos and modern quantum information science. >>

Avadhut V. Purohit, Udaysinh T. Bhosale. Quantum Kicked Top: A Paradigmatic Model. arXiv: 2604.12345v1 [quant-ph]. Apr 14, 2026.

https://arxiv.org/abs/2604.12345

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

Keywords: gst, chaos, entropy, quantum kicked top, quantum chaos, bifurcations, rotational symmetry, time-reversal symmetry, entanglement, qubits, quantum information, entanglement entropy.

# gst: turbulent pair dispersion with stochastic generative diffusion models.

<< ️Recent advances in data-driven modeling have shown that diffusion models can successfully generate synthetic Lagrangian trajectories in turbulent flows. Building on this progress, (AA) extend the method to the joint generation of pairs of Lagrangian velocity trajectories, enabling a fully data-driven representation of turbulent pair dispersion, a long-standing fundamental problem with broad relevance in fluid dynamics. >>

<< ️(They) demonstrate that diffusion models accurately reproduce the evolution of particle-pair separation, including deviations from Richardson's classical scaling law, while simultaneously preserving all key single-particle statistical properties reported in previous studies. These findings underscore the potential of diffusion-based generative models to emulate high-dimensional, multi-scale turbulent dynamics, further establishing them as a powerful tool for scientific modeling and for future geophysical and astrophysical applications. >>

Pantera A., Biferale L., Buzzicotti M., et al. Turbulent pair dispersion with Stochastic Generative Diffusion Models. arXiv: 2604.12932v1 [physics.flu-dyn]. Apr 14, 2026.

https://arxiv.org/abs/2604.12932

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

Keywords: gst, turbulence, waves, diffusion models, turbulent flows, turbulent pair dispersion, stochastic generative diffusion models (DM), direct numerical simulation (DNS).

# gst: chaos and quantum tunneling.

<< ️In generic Hamiltonian systems that are neither completely integrable nor fully chaotic, phase space consists of a mixture of regular and chaotic components. In classical dynamics, transitions between different invariant sets in phase space are strictly forbidden, and these sets act as dynamical barriers to one another. In quantum mechanics, in contrast, wave effects allow transitions through such dynamical barriers. This process, known as dynamical tunneling, refers to penetration through dynamical barriers in phase space and was first recognized in the early 1980s. Since then, various aspects of dynamical tunneling have been elucidated, significantly advancing our understanding of such a novel quantum phenomenon. >>

<< ️In this article, (AA) provide an overview of several phenomenological perspectives of dynamical tunneling, including chaos-assisted and resonance-assisted tunneling, and also introduce approaches based on classical mechanics extended into the complex domain. In particular, (They) seek to clarify what is meant by the common claim that "chaos leads to an enhancement of the tunneling probability", which is often made when dynamical tunneling is dressed. (They) discuss what regime this refers to and, if such an enhancement occurs, what its likely origin is. >>

Akira Shudo. Chaos and Quantum Tunneling. arXiv: 2604.12926v1 [nlin.CD]. Apr 14, 2026.

https://arxiv.org/abs/2604.12926

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

Keywords: gst, waves, chaos, transitions, dynamical tunneling, chaos-assisted tunneling, resonance-assisted tunneling.

# gst: quantum walk on a random comb.

<< ️(AA) study continuous time quantum walk on a random comb graph with infinite teeth. Due to localization effects along the spine, the walk cannot go to infinity in the spine direction, while it can escape to infinity along the teeth of the comb. Starting from an initial vertex the walk has a nonzero probability to stay trapped in a finite region. These results are obtained by studying the spectrum and eigenstates of the random Hamiltonian for the graph and analysing its properties. (They) use both analytic and numerical methods many of which come from the theory of Anderson localization in one dimension. >>

François David, Thordur Jonsson. Quantum walk on a random comb. arXiv: 2604.00908v1 [quant-ph]. Apr 1, 2026.

https://arxiv.org/abs/2604.00908

Also: Francois David, Thordur Jonsson (2021). Quantum walk on a comb with infinite teeth. 

https://arxiv.org/abs/2107.08866    Bergfinnur Durhuus, Thordur Jonsson, John Wheater (2005). Random walks on combs. 

https://arxiv.org/abs/hep-th/0509191

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

Keywords: gst, combs, walk, quantum walk, escape, randomness.

# jazz: black hole blues

<< Black Hole Blues is Quadrature’s debut album. The quartet grew out of the long-running Brooklyn Raga Massive jam sessions and effortlessly brings together a dazzling, charming and ingenious fusion of Indian raga, rock, jazz, psychedelia, and world music influences. >>

Tyler Bennet. Jazz, Raga, And Black Holes: Quadrature Plots Debut Black Hole Blues. World Music Central. Apr 5, 2026.

https://worldmusiccentral.org/jazz-raga-and-black-holes-quadrature-plots-debut-black-hole-blues/

https://youtu.be/yXIggbjLydo

Also: jazz, sound, music, jamming, black hole, dance, in https://www.inkgmr.net/kwrds.html 

Keywords: jazz, sound, music, jamming, black hole, dance

# gst: dispersive shock waves in periodic lattices.

<< ️(AA) introduce and systematically investigate the generation of dispersive shock waves, which arise naturally in physical settings such as optical waveguide arrays and superfluids confined within optical lattices. The underlying physically relevant model is a nonlinear Schrödinger (NLS) equation with a periodic potential. (They) consider the evolution of piecewise smooth initial data composed of two distinct nonlinear periodic eigenmodes. >>

<< ️️The resulting tight-binding approximation is shown to display higher-fidelity for deeper periodic potentials. This reduced (discrete) DNLS model effectively models the dynamics at the minima of the periodic potential of the original continuum NLS. >>

Su Yang, Sathyanarayanan Chandramouli, P. G. Kevrekidis. Dispersive shock waves in periodic lattices. arXiv: 2511.14549v3 [nlin.PS]. Apr 9,  2026.

https://arxiv.org/abs/2511.14549

Phys. Rev. E 113, 044204. Apr 10, 2026.

https://journals.aps.org/pre/abstract/10.1103/sppv-dr5c

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

Keywords: gst, waves, dispersive shock waves.

# gst: unidirectional flow from continuous broken symmetries.

<< ️Locally broken symmetries are used across fields to transport matter, particles and information in preferential directions. Beyond local mechanisms, spatially distributed nonlinearities in crystalline media have enabled non-reciprocal transport, a rectification mechanism that operates continuously across scales and frequencies. Here, (AA) show that this concept applies beyond condensed matter, to fluid transport in living organisms and artificial systems. >>

<< ️(They) take the example of the lymphatic vascular system, which transports interstitial fluid in mammals, and demonstrate that distributed leaflets act as continuous broken symmetries. (They) build an artificial model of a collecting lymphatic and investigate the naturally richer dynamics of unidirectional transport that arises from spatiotemporal excitations. (They) observe robust and scalable transport for any waveshape and external pressure gradients. (They) show experimentally and theoretically that the contraction wavelength, directionality, and pulsatility control the flow rate. In particular, (They) counterintuitively find waveshapes that maximize transport when propagating against the direction of the flow. >>

<< ️Overall, (Their) findings advance the understanding of unidirectional fluid transport in living systems and beyond, and reveal how coupling nonlinearities with spatiotemporal excitations can tune such transport across fields. >>

Aaron Winn, Justine Parmentier, Eleni Katifori, et al. Unidirectional flow from continuous broken symmetries. arXiv: 2603.27474v1 [cond-mat.soft]. Mar 29, 2026.

https://arxiv.org/abs/2603.27474

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

Keywords: gst, waves, particle, non-reciprocal transport, broken symmetries, spatiotemporal excitations, lymphatic vascular system.

# gst: extreme (rogue) waves; from theory to experiments.

<< ️In this Chapter, (AA) review key theoretical and experimental advances in the study of extreme nonlinear wave events, called rogue waves (RWs), in both single-component attractively interacting and two-component repulsive mixtures of ultracold quantum gases. Starting from the exact rational solutions of the integrable focusing nonlinear Schroedinger model, the hierarchy of RW solutions is exemplified. These range from the Peregrine soliton (PS) and, related to it, the destabilization into a multi-peak cascade of PSs dubbed "Christmas-tree", to the Akhmediev breather, and Kuznetsov-Ma soliton as well as higher-order RWs. Emphasis is placed on their controllable dynamical emergence and characteristics in non-integrable quantum many-body systems described by Gross-Pitaevskii models and extensions thereof through different protocols such as modulational instability, gradient catastrophe, and dam-break flows. >>

<< ️(They) further discuss how immiscible particle-imbalanced repulsive mixtures can be cast into effective attractive single-component environments capable of hosting RWs. Next, state-of-the-art experimental techniques are summarized within the ultracold realm that can be utilized to realize solitary waves, modulational instability, dispersive shock waves and RWs including the very recent first experimental observation of the PS, enabled through engineered effective focusing interactions and precise dynamical triggering. >>

<< ️Observations of these extreme events in water waves, nonlinear optics and beyond are also outlined, highlighting their broader relevance and potential of emergence in disparate physical settings. (Their) exposition aims at showcasing ultracold atomic gases as versatile platforms for controllably generating and probing extreme nonlinear events, among others, in the quantum realm across integrable and non-integrable settings. >>

A. Chabchoub, P. Engels, P. G. Kevrekidis, et al. Extreme (Rogue) Waves: From Theory to Experiments in Ultracold Gases and Beyond. arXiv: 2603.25908v1 [cond-mat.quant-gas]. Mar 26, 2026.

https://arxiv.org/abs/2603.25908

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

Keywords: gst, extreme events, rogue waves, solitary waves, dispersive shock waves, modulational instability, gradient catastrophe, dam-break flows, Peregrine soliton, PS Christmas-tree, Akhmediev breather, Kuznetsov-Ma soliton.

# gst: evolving fractal dimensions in iterative bicolored percolation.

<< ️Criticality is traditionally regarded as an unstable, fine-tuned fixed point of the renormalization group. (AA)  introduce an iterative bicolored percolation process in two dimensions and show that it can both preserve criticality and transform fractal dimensions. >>

<< ️Starting from critical configurations, such as the O⁡(𝑛) loop and fuzzy Potts models, successive coarse graining generates a hierarchy of distinct yet critical generations. Using the conformal loop ensemble, (They) derive exact, generation-dependent fractal dimensions, which are quantitatively confirmed by large-scale Monte Carlo simulations. The evolutionary trajectory depends not only on the universality class of the initial state but also on whether it possesses a two-state critical structure, leading to different critical exponents starting from site and bond percolation. >>

<< ️These results establish a general geometric mechanism for evolving fractal dimensions, in which scale invariance persists across generations. >>

Shuo Wei, Haoyu Liu, Xin Sun, et al. Evolving fractal dimensions in iterative bicolored percolation. Phys. Rev. E 113, L032102. Mar 23, 2026.

https://journals.aps.org/pre/abstract/10.1103/s2ql-zxz6#4eafda38-c97e-4656-8034-9a3682fa0218

arXiv: 2511.18462v2 [cond-mat.stat-mech]. Mar 24, 2026. 

https://arxiv.org/abs/2511.18462

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

Keywords: gst, order, disorder, fluctuations, percolation, fractal dimensions, criticality, coarse-graining transformations.

# gst: apropos of escape, Stochastic Web Map; survival probability and escape frequency.

<< ️(AA) study transport and escape in the Stochastic Web Map (SWM), an area-preserving system with phase-space structure controlled by a symmetry parameter q and nonlinearity K. By analyzing the survival probability P_S(n) and escape frequency P_E(lnn), (They) show that in the chaotic regime escape dynamics is governed by a single time scale n_(typ) ∝ K^(−2)h^(2); here h is the size of the escape horizon. Deviations at large K and small h indicate a breakdown of the quasilinear approximation. Then, upon rescaling the time by n_(typ), escape statistics becomes universal, independent of q. These results demonstrate that escape is controlled by global transport rather than symmetry. >>

K. B. Hidalgo-Castro, J. A. Méndez-Bermúdez, Edson D. Leonel. Stochastic Web Map: Survival probability and escape frequency. arXiv: 2603.20888v1 [nlin.CD]. Mar 21, 2026.

https://arxiv.org/abs/2603.20888

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

Keywords: gst, escape, escape horizon, chaos, global transport.

# gst: phase-space organization of the elastic pendulum; chaotic fraction, energy exchanges, and the order-chaos-order transition.

<< ️(AA) study the phase-space organization of the planar elastic pendulum as a function of its two dimensionless control parameters: the reduced energy R and the squared frequency ratio µ. By randomly sampling the isoenergetic volume to classify trajectories as oscillatory, rotational, or chaotic across the (µ,R) parameter plane, (They) obtain a global portrait of the coexistence and competition between dynamical regimes. >>

<< ️The chaotic fraction is not uniformly distributed across the parameter plane but concentrates in a well-defined central cloud whose ridge follows a linear relation in the (µ,R) plane and whose maximum does not exceed 70% of the available phase space. The order-chaos-order transition is not a global property of the parameter plane but occurs specifically in the central region surrounding this cloud: along paths that traverse it, oscillatory orbits progressively give way to chaotic trajectories, which in turn yield to rotational orbits as the energy grows, revealing a clear sequential mechanism underlying the transition. >> 

<< ️The onset of rotational motion is gradual rather than sharp, reflecting a strong dependence on initial conditions. By decomposing the total energy into spring-like, pendulum-like, and coupling contributions, (They) establish a direct correspondence between the coupling power and the abundance of chaotic trajectories, showing that enhanced inter-mode energy exchange is a reliable indicator of dynamical complexity. >>

Juan P. Tarigo, Cecilia Stari, Edson D. Leonel, et al. Phase-space organization of the elastic pendulum: chaotic fraction, energy exchanges, and the order-chaos-order transition. arXiv: 2604.01503v1 [nlin.CD]. Apr 2, 2026.

https://arxiv.org/abs/2604.01503

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

Keywords: gst, pendulum, planar elastic pendulum, rotation, rotational motion, chaos, transitions, order-chaos-order transition. 

# gst: entropy production rate in stochastically time-evolving asymmetric networks.

<< ️Fluctuations in parameters that are typically treated as fixed play a crucial role in the behavior of complex systems. However, to date, we lack a general non-equilibrium thermodynamic treatment of such a complex system. In this Letter, to address this problem, (AA) develop a framework in which fluctuating interactions between units of nonlinear network systems are modeled as uncorrelated colored noise (i.e., annealed disorder) with a correlation time. >>

<< ️This approach enables us to quantify how the entropy production rate (EPR) depends on both the characteristic time-scale and the strength of the disorder. Using dynamical mean field theory, (They) derive an exact expression for EPR at any transient time that is validated by simulations of the full non-linear dynamics. At stationarity, a relation between EPR and autocorrelation is established and then used to analytically study the particular case of linear systems. >>

Tuan Pham, Deepak Gupta. Entropy Production Rate in Stochastically Time-evolving Asymmetric Networks. arXiv: 2603.27658v1 [cond-mat.stat-mech]. Mar 29, 2026.

https://arxiv.org/abs/2603.27658

Also: network, noise, order, disorder, fluctuations, entropy, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, network, entropy, noise, order, disorder, fluctuations.

# gst: variational iterative rotation algorithm, combinatorial optimization with classical kicked tops.

<< ️(AA) investigate a classical formulation of the Quantum Approximate Optimization Algorithm (QAOA), realized as a Hamiltonian dynamical system of classical kicked tops, which (They) call the Variational Iterative Rotation Algorithm (VIRAL). The variational parameters are the transverse and longitudinal rotation angles at each of the p layers of the circuit. >>

<< ️(They) find that VIRAL outperforms QAOA on the canonical Sherrington-Kirkpatrick spin-glass benchmark at all circuit depths, with the energy density converging to the ground state value linearly in 1/p. For large circuit depths, the optimized dynamics follows a Floquet protocol in which a pitchfork bifurcation destabilizes the equatorial fixed point and drives the spins toward polar Ising configurations. >>

<< ️(Their) results demonstrate that the effectiveness of QAOA-like protocols derives primarily from their underlying iterative rotation structure, and that a classical implementation of it outperforms its quantum counterpart. (They) further elucidate its efficiency by reducing the many-body classical evolution to an effective Landau-Lifshitz dynamics for a single spin in a stochastic magnetic field. In this picture, the covariance matrix of the effective field reveals a nearly rank-one structure in which a single mode dominates the stochastic dynamics. In contrast, quantum fluctuations make the noise covariance of the effective quantum model of higher rank, hampering the control of the system. >>

Flaviano Morone, Andrew D. Kent, Dries Sels. Variational Iterative Rotation Algorithm: Combinatorial Optimization with Classical Kicked Tops. arXiv: 2604.01512v1 [cond-mat.dis-nn]. Apr 2, 2026.

https://arxiv.org/abs/2604.01512

Also: rotation, in FonT https://flashontrack.blogspot.com/search?q=rotation

Keywords: gst, kicked top, rotation, pitchfork bifurcation, quantum fluctuations. 

# gst: comparative analysis of detonation and shock waves interacting with droplets.

<< ️The interaction mechanisms among detonation waves, shock waves, and liquid droplets play a critical role in advancing propulsion technologies such as rotating detonation engines. This (AA) study conducts a detailed comparison of wave dynamics, cavitation phenomena, and droplet deformation during the detonation wave and the shock-wave interactions with a water droplet, employing a high-resolution numerical model that integrates multicomponent compressible fluid dynamics, chemical reactions, and phase transition effects. >>

<< ️Numerical simulations reveal distinct characteristics between detonation and shock-induced phenomena. Unlike the shock wave, detonation-induced reflected shock waves exhibit significantly higher propagation velocities while maintaining nearly identical wave configurations, a phenomenon this (AA) study mechanistically explains by the unique postwave conditions. >> 

<< ️A fundamental distinction arises in cavitation dynamics between the detonation wave and the shock wave, with the detonation-wave triggering cavitation zone collapse at significantly higher rates compared with the shock wave. This difference is attributed to the shorter persistence of low-pressure regions behind the detonation front, where rapid attenuation of postwave pressure and flow velocity occurs. >>

<< ️Moreover, detonation-induced flow interactions create unique droplet fragmentation patterns. The rapid postwave velocity reduction prevents Rayleigh-Taylor instability-driven forward jet formation, instead causing leeward-side flattening of the droplet through the vortex in the recirculation zone. >>

Hanbing Zou, Xin Jin, Haotian Chen, et al. Comparative analysis of detonation  and shock waves interacting with droplets: Characteristics and mechanisms. Phys. Rev. Fluids 11, 034303. Mar 18, 2026.

https://journals.aps.org/prfluids/abstract/10.1103/mp9z-tlk3  

Also: waves, drop, droplet, droploid, bubble, collapse, vortex, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, waves, shock-waves, drop, droplet, droploid, bubble, collapse, vortex, transitions, phase transition, cavitation, detonation wave, detonation front, droplet fragmentation patterns. 

# gst: to tune to a damage, the damage spreading transition.

<< ️Deterministic classical cellular automata can be in two phases, depending on how irreversible the dynamical rules are. In the strongly irreversible phase, trajectories with different initial conditions coalesce quickly, while in the weakly irreversible phase, trajectories with different initial conditions can remain different for a time exponential in the system volume. The transition between these phases is referred to as the damage-spreading transition (the "damaged" sites are those that differ between the trajectories). >>

<< ️(AA) develop a theory for this transition. In the simplest and most generic setting, the transition is known to be related to directed percolation, one of the best-studied nonequilibrium phase transitions. However, (They) show that full theory of the damage-spreading critical point is richer than directed percolation, and contains an infinite hierarchy of sectors of local observables. >>

<< ️Directed percolation describes the first level of the hierarchy. The higher observables include "overlaps" for multiple trajectories, and may be labeled by set partitions. (These higher observables arise naturally if, for example, we consider decay of entropy under the irreversible dynamics.). The full hierarchy yields a hierarchy of nonequilibrium fixed points for reaction-diffusion-type processes, all of which contain directed percolation as a subsector, but which possess additional universal critical exponents. >>

Adam Nahum, Sthitadhi Roy. The damage spreading transition: a hierarchy of renormalization group fixed points. arXiv: 2603.22439v1 [cond-mat.stat-mech]. Mar 23, 2026.

https://arxiv.org/abs/2603.22439

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

Keywords: gst, transitions, damage, damage-spreading transition, directed percolation. 

# gst: early warning signals for primary and secondary bifurcation to oscillatory instabilities.

<< ️In several natural and engineering systems, changes in control parameters can trigger bifurcations that lead to sustained or growing periodic oscillations, indicating the onset of oscillatory instabilities. Such emergent behaviour often results from positive feedback between interacting subsystems, resulting in large-amplitude oscillations that can be detrimental. >>

<< ️Several precursors are available to provide early warning of an impending oscillatory instability. In reality, practical systems may exhibit different sequences of bifurcations, including a primary bifurcation to an oscillatory state that may be either continuous or abrupt, followed by an abrupt secondary bifurcation, and further transitions beyond the secondary bifurcation. Existing precursors for oscillatory instabilities typically forewarn the onset of the primary bifurcation to an oscillatory state and tend to saturate once the system enters the oscillatory regime. Notably, primary bifurcations often involve lower amplitudes compared to the more severe states after secondary bifurcation. >>

<< ️In this study, (AA) propose a methodology based on spectral visibility graphs to get forewarning for both primary and secondary bifurcations. The method inherently captures the evolution of the harmonic content of the signal relative to other frequency components. The approach employs tuning of a single sensitivity parameter to detect different sequences of bifurcation. (They) demonstrate the usefulness of (Their) method for thermo-acoustic and aero-acoustic instabilities in multiple engineering systems involving turbulent flow and reactions. (Their) methodology can help systems prepare in advance or even avoid undesirable transitions. Tuning the sensitivity parameter allows adaptive, risk-based warnings, ensuring high performance without tipping into undesirable regimes. >>

Rohit Radhakrishnan, Prasana Kumar, Induja Pavithran, et al. Early warning signals for primary and secondary bifurcation to oscillatory instabilities. arXiv: 2603.24068v1 [physics.flu-dyn]. Mar 25, 2026.

https://arxiv.org/abs/2603.24068

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

Keywords: gst, instability, turbulence, transitions, bifurcation, feedback.

# 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: apropos of different degrees of decimation, reduction of triadic interactions suppresses intermittency and anomalous dissipation in turbulence.

<< ️(AA) investigate how the defining statistical features of three-dimensional turbulence respond to systematic reductions of the Fourier-space triadic interaction network. Using direct numerical simulations of both fractally and homogeneously decimated Navier-Stokes dynamics, (They) show that progressive thinning of the set of active modes leads to a systematic suppression of intermittency and, most strikingly, to the vanishing of the mean dissipation rate in the large-Reynolds-number limit. >>

<< ️Structure-function exponents collapse onto their dimensional values, the multifractal singularity spectrum contracts, and the analyticity width extracted from the exponential spectral tail increases monotonically with decimation-each indicating a substantial regularization of the velocity field. >>

<< ️Together, these results provide direct evidence that anomalous dissipation in incompressible turbulence is not a generic property of the Navier-Stokes equations, but instead requires the full combinatorial richness of their triadic nonlinear interactions. >>

Anikat Kankaria, Ritwik Mukherjee, Sugan Durai Murugan, et al. Reduction of triadic interactions suppresses intermittency and anomalous dissipation in turbulence. arXiv: 2603.19180v1 [physics.flu-dyn]. Mar 19, 2026.

https://arxiv.org/abs/2603.19180

Also: turbulence, intermittency, dissipation, singularity, collapse, transition, network, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, turbulence, three-dimensional turbulence, incompressible turbulence, intermittency, dissipation, anomalous dissipation, singularity, multifractal singularity spectrum contracts, collapse, transitions, networks, triadic interactions, progressive thinning, decimation.

# gst: apropos of flows of hyperpycnal river plumes

<< ️The flow of a hyperpycnal river plume into a lake with a sloping bed and without any lateral confinement is a common occurrence in nature. A characteristic example of such geophysical fluid flow system is the inflow of river Rhone in Llake Geneva. >>

<< ️In this work, (AA) study the near-field plunging dynamics of an unconfined hyperpycnal plume at laboratory scale, over an idealized bed, with a slope that is similar to the one of the natural system. The study is based on large-eddy simulation of the Navier-Stokes equations in the Boussinesq approximation. (They) focus on the effect of varying the inflow conditions and in particular the densimetric Froude number, Fr_𝑑, which is the nondimensional parameter describing the ratio between inertial and buoyancy forces acting on the plume. >>

<< ️Three simulations were performed at different values of Fr_𝑑, within the range encountered in the natural system. Similarly to previous works, (They) are able to identify lateral slumping as the main mechanism that leads to plunging of the dense river water and the formation of the characteristic triangular pattern at the lake surface. (They) are able to further identify the formation of a wake downstream of the vertex plunge point, due to the transport of mixed river-ambient water from the converging mixing layers across the plunge curve on both sides of the plume. >>

<< ️The extent of both the wake and the overall plunge region increases significantly with increase of Fr_𝑑. This mechanism can be associated to the changes of the surface patterns of the plume observed in the field. In addition, (AA) compute the total entrainment, 𝐸, of ambient lake water as the streamwise increase of volumetric flow rate downstream of the river mouth. 𝐸 is found to increase with distance from the mouth, as the plume continuously entrains ambient lake water. >> 

<< (They) find that for the same distance from the river mouth, 𝐸 is larger for lower Fr_𝑑. This increase of 𝐸 with decreasing Fr_𝑑 is attributed to two mechanisms. First, in the plunge region, lower Fr_𝑑 leads to greater lateral spread and therefore increased interface area between plume and ambient water. Second, in the underflow region, lower Fr_𝑑 results in higher mean streamwise plume velocity, enhancing entrainment intensity. >>

Georgios Giamagas, Cyrille Bonamy, Koen Blanckaert, et al. Plunging and entrainment dynamics of an unconfined hyperpycnal plume over a sloping bed. Phys. Rev. Fluids 11, 033801. Mar 5, 2026.

https://journals.aps.org/prfluids/abstract/10.1103/41p1-sn3p

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

Keywords: gst, vortex, vortices, transitions, unconfined hyperpycnal plume, lateral confinements, near-field plunging dynamics, inertial and buoyancy forces, lateral slumping, wake downstream of the vertex plunge point, lateral spread, streamwise plume velocity.

# gst: geometric dynamics of turbulence; a minimal oscillator structure from non-local closure

<< ️Turbulence remains one of the central open problems in classical physics, largely due to the absence of a closed dynamical description of the Reynolds stress. Existing approaches typically rely either on local constitutive assumptions or on high-dimensional statistical representations, without identifying a minimal set of dynamical variables governing the cascade response. >>

<< ️Here (AA) show that the non-local stress response implied by the Navier-Stokes equations admits a systematic reduction onto a low-dimensional anisotropic sector of the turbulent cascade. This reduction leads to a minimal dynamical system with the structure of a damped oscillator, arising from the coupling between the leading angular mode and its nonlinear transfer to higher-order sectors. >>

<< ️Within this framework, classical turbulent behaviors -- including inertial-range scaling, shear-driven transport, and wall-bounded logarithmic profiles -- emerge as different realizations of the same underlying dynamical structure. Universal quantities such as the Kolmogorov constant and the von Kármán constant appear as leading-order consequences of internal consistency conditions applied across homogeneous and shear-driven regimes. >>

<< ️These results suggest that turbulence admits a minimal dynamical backbone governed by non-local cascade response, providing a unified perspective that connects spectral transfer, anisotropy, and mean-flow interaction within a single reduced framework. >>

Alejandro Sevilla. Geometric Dynamics of Turbulence: A Minimal Oscillator Structure from Non-local Closure. arXiv: 2603.18913v3 [physics.flu-dyn]. Mar 24, 2026. 

https://arxiv.org/abs/2603.18913

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

Keywords: gst, turbulence, cascade response, non-local stress response, damped oscillators, inertial-range scaling, shear-driven transport, wall-bounded log profiles, spectral transfer, anisotropy, mean-flow interaction.

# brain: entraining chimeras, the effect of driving with regular, irregular, and real-world phases.

<< ️Chimera states in coupled oscillator networks are paradigmatic examples of partial synchronization in nonlinear systems, with direct relevance to real-world network dynamics, such as neuronal dynamics. Since real-world networks are not isolated, but embedded in larger interacting systems, chimeras have also been studied under the influence of other networks and external signals. In particular, most prior work has treated periodic forcing of chimeras in the thermodynamic limit. >>

<< ️As a consequence, it remains unclear how chimera states respond to external driving in finite-size networks, where they can spontaneously collapse into full synchronization. It is also largely unknown how realistic noisy drivers, rather than periodic signals, affect driver-response synchronization. >>

<< ️To address these open questions, (AA) drive a finite-size oscillator network that exhibits a chimera state with constant-angular-frequency phases and with the same phases superimposed with noise. (They) find that, for a specific range of angular-frequency mismatch and driving strength, (They) can entrain chimeras without causing them to collapse into full synchronization. Adding noise, in turn, reduces entrainment and facilitates collapses. >>

<< ️As a real-world application of the driven chimera state framework, (AA) also drive chimeras with phases from focal and nonfocal electroencephalography (EEG) signals recorded during seizure-free periods in patients with epilepsy. (They) observe that focal signals yield higher entrainment power, within-network coherence, and collapse power than nonfocal signals when the driver EEG's dominant frequency is close to the chimera's mean angular frequency. Away from this regime, nonfocal signals yield higher values of all three measures. The observed differences not only characterize focal and nonfocal signals, but may also provide additional insight into the seizure-free brain dynamics of epilepsy patients. >>

<< ️In conclusion, beyond quantifying how external driving signals, with or without noise, affect the dynamics of chimera states that can collapse into full synchronization, this (AA) work further bridges the study of chimera states and epilepsy research. >>

Jacopo Epifanio, Martin Brešar, Ralph G. Andrzejak. Entraining chimeras: The effect of driving with regular, irregular, and real-world phases. Phys. Rev. E 113, 034214. Mar 13, 2026.

https://journals.aps.org/pre/abstract/10.1103/vczh-r59d

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

Keywords: gst, brain, chimeras, noise, transitions, collapse, networks, coupled oscillator networks, epilepsy, synchronization, driver-response synchronization. 

# 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: apropos of ab.normal criticalities, a hypothetical scenario of non-normal route to chaos.

<< ️Deterministic chaos is commonly associated with spectral criticality: exponential sensitivity is expected when Jacobian eigenvalues exceed unity in parts of the attractor, producing the local expansion that offsets contraction elsewhere. (AA) show that this paradigm is incomplete in dimensions d>1.  >>

<< ️(They) construct a bounded 3D dynamical system whose Jacobian is pointwise spectrally contracting, namely all instantaneous eigenvalues remain strictly inside the stability region, yet the system develops a positive maximal Lyapunov exponent and undergoes a transition to chaos as a non-normality index increases at fixed spectral radius. The mechanism relies on the repeated regeneration of transient non-normal amplification through endogenous switching that reinjects trajectories into amplifying non-orthogonal directions. >>

<< ️Although demonstrated here for a discrete-time map, the mechanism is geometric and applies more broadly to deterministic dynamical systems. These results show that chaos can emerge without spectral criticality and identify non-normality as an independent route to deterministic chaos. >>

D. Sornette, V.R. Saiprasad, V. Troude. Non-Normal Route to Chaos. arXiv: 2603.08191v1 [nlin.CD]. Mar 9, 2026.

https://arxiv.org/abs/2603.08191

Also:  Virgile Troude, Sandro Claudio Lera, Ke Wu, Didier Sornette. Illusions of Criticality: Crises Without Tipping Points. arXiv: 2412.01833v5 [nlin.CD]. Oct 3, 2025. https://arxiv.org/abs/2412.01833

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

Keywords: gst, chaos, criticality, transitions, non-normality, transient non-normality, reinjection via endogenous switch.

# gst: geometry of contraction-induced flows.

<< ️Peristalsis is the driving mechanism behind a broad array of biological and engineered flows. In peristaltic pumping, a wavelike contraction of the tube wall produces local changes in volume which induce flow. Net flow arises due to geometric nonlinearities in the momentum equation, which must be properly captured to compute the flow accurately. >>

<< ️While most previous models focus on radius-imposed peristalsis, they often neglect longitudinal length changes—a natural consequence of radial contraction in elastic materials. In this paper, to capture a more accurate picture of peristaltic pumping, (AA) calculate the flow in an elastic vessel undergoing contractions in the transverse and longitudinal directions simultaneously, keeping the geometric nonlinearities arising in the strain. >>

<< ️(They) demonstrate that transverse and longitudinal contractions induce instantaneous flows at the same order in wall strain but in opposite directions. (They) investigate the influence of the wall's Poisson ratio on the flow profile. Incompressible walls suppress flow by minimizing local volume changes, whereas auxetic walls enhance flow. For radius-imposed peristaltic waves, wall incompressibility reduces both reflux and particle trapping. In contrast, length-imposed waves typically generate backflow, although trapping can still occur at large amplitudes for some Poisson ratios. >>

Aaron Winn, Eleni Katifori. Geometry of contraction-induced flows. Phys. Rev. Fluids 11, 033101. Mar 12, 2026.

https://journals.aps.org/prfluids/abstract/10.1103/pw9s-vvf4

arXiv: 2510.24016v1 [physics.flu-dyn]. Oct 28, 2025.

https://arxiv.org/abs/2510.24016

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

Keywords: gst, waves, elasticity, networks, peristalsis, peristaltic pumping, peristaltic waves, wavelike contractions, transverse and longitudinal contractions, longitudinal length changes, instantaneous flows, auxetic walls, backflows.

# 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: prolate and oblate nematic shells under equal and hybrid alignments.

<< ️Using the Landau–de Gennes free-energy formalism with the fast inertial relaxation engine relaxation method, (AA) investigate the role of geometry and anchoring conditions in nematic liquid crystal shells. Both prolate and oblate geometries are explored for four distinct anchoring configurations: degenerate planar on both surfaces, homeotropic on both surfaces, and hybrid cases with planar-homeotropic and homeotropic-planar alignments. (Their) simulations reveal a rich variety of topological defect arrangements, including bipolar configurations with boojums; tetrahedral patterns featuring disclination lines, boojums, and hedgehogs; Saturn-ring structures; and twisted director fields in the equatorial plane. >>

<< ️Detailed energy analyses demonstrate that elastic distortions—splay, bend, and twist—are strongly influenced by parameters such as inner and outer radii, shell thickness, and aspect ratio, which in turn dictate the stabilization of specific defect structures. ️These findings provide insights into the curvature-driven mechanisms that control the formation of defects in nematic shells. >>

F. C. Cruz, E. K. Lenzi, Q. Li, et al. Prolate and oblate nematic shells under equal and hybrid alignments. Phys. Rev. E 113, 035403. Mar 4, 2026.

https://journals.aps.org/pre/abstract/10.1103/3ynk-2nsp

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

Keywords: gst, spheroids, elasticity, nematic liquid crystal shells, prolate and oblate geometries, topological defects, elastic distortions, curvature-driven mechanisms.

# gst: predicting oscillations in complex networks with delayed feedback.

<< ️Oscillatory dynamics are common features of complex networks, often playing essential roles in regulating function. Across scales from gene regulatory networks to ecosystems, delayed feedback mechanisms are key drivers of system-scale oscillations. >> 

<< ️The analysis and prediction of such dynamics are highly challenging, however, due to the combination of high-dimensionality, non-linearity and delay. Here, (AA) systematically investigate how structural complexity and delayed feedback jointly induce oscillatory dynamics in complex systems, and introduce an analytic framework comprising theoretical dimension reduction and data-driven prediction. >>

<< ️(They) reveal that oscillations emerge from the interplay of structural complexity and delay, with reduced models uncovering their critical thresholds and showing that greater connectivity lowers the delay required for their onset. (Their) theory is empirically tested in an experiment on a programmable electronic circuit, where oscillations are observed once structural complexity and feedback delay exceeded the critical thresholds predicted by our theory. >>

<< ️Finally, (They) deploy a reservoir computing pipeline to accurately predict the onset of oscillations directly from timeseries data. (AA) findings deepen understanding of oscillatory regulation and offer new avenues for predicting dynamics in complex networks. >>

Shijie Liu, Jinliang Han, Jianming Liu, et al. Predicting oscillations in complex networks with delayed feedback. arXiv: 2603.04251v2 [cond-mat.dis-nn]. Mar 4, 2026.

https://arxiv.org/abs/2603.04251

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

Keywords: gst, networks, oscillatory dynamics, oscillatory regulations, system-scale oscillations, delay, delayed feedback mechanisms, criticality, critical thresholds.

# gst: localization of information driven by stochastic resetting.

<< ️The dynamics of extended many-body systems are generically chaotic. Classically, a hallmark of chaos is the exponential sensitivity to initial conditions captured by positive Lyapunov exponents. Supplementing chaotic dynamics with stochastic resetting drives a sharp dynamical phase transition: (AA) show that the Lyapunov spectrum, i.e., the complete set of Lyapunov exponents, abruptly collapses to zero above a critical resetting rate. >>

<< ️At criticality, (They) find a sudden loss of analyticity of the velocity-dependent Lyapunov exponent, which (They) relate to the transition from ballistic scrambling of information to an arrested regime where information becomes exponentially localized over a characteristic length diverging at criticality with an exponent 𝜈=1/2 and a dynamical exponent 𝑧=2. (They) illustrate (Their) analytical results on generic chaotic dynamics by numerical simulations of coupled map lattices. >>

Camille Aron, Manas Kulkarni. Localization of information driven by stochastic resetting. Phys. Rev. E 113, L022101. Feb 23, 2026.

https://journals.aps.org/pre/abstract/10.1103/pkgb-mp8s

arXiv:2510.07394v2 [cond-mat.stat-mech]. Feb 24, 2026.

https://arxiv.org/abs/2510.07394

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

Keywords: gst, chaos, transition, collapse, randomness, stochasticity, stochastic resetting, phase transition, criticality, critical resetting rate, ballistic scrambling of information.

# sound: screeching sound of peeling tape.

<< ️The screeching of peeling tape is a familiar albeit annoying sound. However, despite decades of study, its source has remained elusive. Herein (AA) demonstrate that this sound is produced by a discrete train of weak shocks emanating from the fine fractures which travel supersonically with respect to the surrounding air, in the transverse direction within the detaching adhesive. >>

<< ️Each sound pulse is generated when a fracture tip reaches the edge of the tape. (They) verify this using two microphones synchronized with clips from two simultaneous high-speed video cameras, one observing the fracture motions in the adhesive through the transparent substrate, while the other captures schlieren imaging of the shock fronts in the air. >>

Er Qiang Li, Paul W. Riker, Sriram Rengarajan, et al. Screeching sound of peeling tape. Phys. Rev. E 113, 025508. Feb 24, 2026.

https://journals.aps.org/pre/abstract/10.1103/p19h-9ysx

Also: sound, noise, fracture, crack, jazz, in https://www.inkgmr.net/kwrds.html 

Keywords: sound, noise, fracture, crack, screeching, discrete train of weak shocks, jazz