# gst: apropos of reflex instabilities, the reflex motion of the central object drives at least seven instabilities in accretion discs.

<< This series of papers studies the stability of accretion discs to the reflex motion of the central object under the gravitational pull of the disc itself. In this second paper, (AA) use linear analysis to reproduce or discover seven distinct instabilities. >>

<< (AA) outline their defining characteristics and propose a classification. Of the four instabilities that had already been discovered, three are artificial: one does not survive the transition to modern surface density profiles such as power-laws, one is due to the location of the domain's boundaries, and one is due to the use of damping layers near the domain's boundaries. Only the SLING instability of Adams et al. (1989) and the three new 'cavity' instabilities seem capable of affecting accretion discs. >>

<< All four can be described to a high degree of precision by WKB methods. They may drive eccentricity growth, affect planet migration, create spiral and crescent substructures in the absence of any planet, and boost accretion onto the central object. The issue is that the three artificial instabilities are extremely hard to avoid in simulations, and would bias the same observables. >>

Nathan Magnan, Michel Tagger, Clément Baruteau, et al. Reflex instabilities II: The reflex motion of the central object drives at least seven instabilities in accretion discs. arXiv: 2610.08472v1 [astro-ph.EP]. Oct 6, 2026.

https://arxiv.org/abs/2610.08472

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

Keywords: gst, instability, waves, transition, astrophysics, accretion discs, reflex instability, damping layers, SLING instability, cavity instability. 

# life: timescale-induced synchronization of contrarians in adaptive dynamical networks.

<< ️From the firing of neurons to the formation of social consensus, the interplay between conformist and contrarian behaviors regulates collective dynamics. (AA) unravel how adaptation timescales induce distinct synchronization behaviors in mixed populations of conformists and contrarians. >>

<< While slow adaptation leaves contrarians in a persistent state of incoherence, fast adaptation traps them into a scaffold formed by conformists, stabilized by rapid feedback from the evolving network structure, leading to the emergence of synchronized clusters. Notably, contrarians are entrained only within an intermediate coupling window and require a conformist majority. >>

<< ️(AA) analytically reduce a low-dimensional description using a collective coordinate approach and demonstrate that a conformist majority and a threshold adaptation rate are necessary conditions for contrarians to synchronize in adaptive networks, which agrees well with numerical simulations. (Their) results highlight the critical role of adaptation timescales in reshaping collective behaviors in mixed populations, offering insights into consensus formation and polarization in adaptive social networks. >>

Akash Yadav, V.K. Chandrasekar, D.V. Senthilkumar. Timescale-induced synchronization of contrarians in adaptive dynamical networks. Phys. Rev. E 114, 044310. Oct 13, 2026.

https://journals.aps.org/pre/abstract/10.1103/v1vq-skr1

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

Keywords: behav, networks, collective dynamics, synchronization, synchronization transition, coupled oscillators, threshold adaptation rate.

# gst: vortex clusters and vortex-filled bubbles in a modified Abelian-Higgs model.

<< (AA) investigate a single-component Abelian-Higgs model with an eighth-order scalar potential whose vacuum manifold consists of two disconnected circles. The model supports two species of vortices and domain walls interpolating between the two vacuum components. (They) find type-1.5-like behavior characterized by nonmonotonic intervortex interactions and bound states of spatially separated vortices. >>

<< Inner-vacuum vortices form clusters through short-range repulsion and long-range attraction, whereas outer-vacuum vortices form vortex-filled bubbles in which a closed domain wall confines multiple inner-vacuum-vortex cores. >>

<< (AA) construct the domain wall analytically, derive the asymptotic vortex-wall interactions, and analyze the fluctuation spectra of coincident multivortices to identify their splitting instabilities. >>

D. Miguélez-Caballero, S. Navarro-Obregón, Muneto Nitta, et al. Vortex clusters and vortex-filled bubbles in a modified Abelian-Higgs model. arXiv: 2610.21930v1 [hep-th]. Oct 15, 2026.

https://arxiv.org/abs/2610.21930

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

Keywords: gst, vortex, bubbles, instability, transitions, short-range repulsion, long-range attraction.

# gst: chaotic Griffiths phase in neuron map networks.

<< ️Griffiths phases provide a mechanism for sustaining critical dynamics over extended parameter regions without fine-tuning to an isolated transition point. This behavior has been mainly associated with structural heterogeneity in complex networks. >>

<< ️Here (AA) show that quenched heterogeneity in local parameters can generate a chaotic Griffiths phase in a network of map-based neurons. (They) study globally coupled Chialvo maps with quenched disorder in a local neuronal parameter, thereby isolating intrinsic parameter disorder from topological disorder. >>

<< ️As the coupling strength is varied, a chaotic Griffiths phase emerges between desynchronized and coherent chaotic dynamics, characterized by intermittent formation and breakup of neuronal clusters and large fluctuations in the fraction of clustered neurons. Within this regime, cluster sizes exhibit power-law distributions with coupling-dependent exponents, providing evidence of critical behavior over a finite parameter interval. >> 

<< ️The chaotic Griffiths phase is absent in the homogeneous limit and broadens progressively as the degree of parameter heterogeneity increases. (AA) further introduce topological disorder through small-world connectivity and find that its combined action with local parameter heterogeneity substantially extends the chaotic Griffiths phase. In both globally coupled and small-world networks, the number of positive Lyapunov exponents displays anomalous scaling with system size. >> 

<< ️These results demonstrate that intrinsic dynamical heterogeneity constitutes an independent mechanism for generating chaotic Griffiths phases and that its interplay with structural disorder enhances extended criticality in neuronal networks. >>

Juan Velez-Rojas, M.G. Cosenza. Chaotic Griffiths phase in neuron map networks. arXiv: 2610.03344v1 [nlin.CD]. Oct 2, 2026.

https://arxiv.org/abs/2610.03344

Also: network, brain, neuro, intermittency,  fluctuations, disorder, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, networks, brain, neurons, intermittency, disorder, fluctuations, quenched heterogeneity, quenched disorder, structural disorder, chaotic Griffiths phase, criticality.

# gst: using analogues to investigate error growth and predictability in turbulence.

<< ️In this study, (AA) revisit Lorenz's pioneering concept of analogues to investigate error growth and predictability in fully developed turbulence using experimental data. By applying the method to a 1D turbulent velocity time series, (They) successfully identify the three error growth regimes intuited by Lorenz and later formalized by turbulence theory: the chaotic exponential regime, the algebraic regime of spontaneous stochasticity, and the saturation regime. >>

<< (AA) analysis reveals that the Lyapunov exponent and the exponent of the algebraic regime depend on the initial error. (They) interpret this dependence as a statistical bias induced by the intermittency of turbulence, where rare events, characterized by lower Lyapunov exponents and more singular velocity increments, are preferentially sampled when considering larger initial errors. >>

<< ️These findings not only validate Lorenz's qualitative intuition but also provide new quantitative insights into the predictability of turbulent flows, paving the way for potential applications in the prediction of extreme events. >>

Carlos Granero-Belinchon, Mickaël Bourgoin, Bérengère Dubrulle. Using analogues to investigate error growth and predictability in turbulence. arXiv: 2610.11796v1 [physics.flu-dyn]. Oct 8, 2026.

https://arxiv.org/abs/2610.11796

Also: chaos, turbulence, error, analogy, intermittency, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, chaos, turbulence, error, analogy, intermittency, rare events, Lorenz's error growth regimes, chaotic exponential regime, algebraic regime of spontaneous stochasticity, saturation regime, transitions.

# life: scaling laws for the spread of defection in evolutionary games on networks.

<< ️(AA) study the spread of defection in evolutionary games on networks using deterministic replicator dynamics posed on graphs. Each node hosts a mixed population of cooperators and defectors interacting through a Prisoner's Dilemma payoff matrix, with nearest-neighbor coupling determined by the network adjacency matrix. >>

<< ️(AA) develop two complementary analytical approximations that quantify how network architecture influences the timescale over which cooperation collapses. In a weak-coupling regime, internode interactions act as a small perturbation, yielding explicit approximate solutions on general graphs. For networks with strongly heterogeneous degree distributions, (They) derive a quasisteady approximation based on the natural separation of timescales between high- and low-degree nodes. >>

<< ️Using these approximations, (AA) introduce a defection spreading-time metric and show that the collapse of cooperation exhibits robust power-law scaling with system size across a broad range of network topologies. Analytical predictions are validated numerically on lattices, star graphs, incrementally connected graphs, small-world networks, and scale-free networks. >>

<< ️The (AA) analysis shows that, to leading order, defection dynamics are controlled by local nodal degree, while network coupling and degree heterogeneity provide secondary corrections that influence the global collapse dynamics. (They) further show that increasing degree heterogeneity increases the average defection time, providing a complementary spectral interpretation through the principal eigenvalue of the adjacency matrix and related measures of graph irregularity. >>

<< ️These results quantify how network architecture controls the transient dynamics of evolutionary collapse and establish new connections between evolutionary game dynamics and spreading processes on networks. >>

M. Giles, P.K. Newton. Scaling laws for the spread of defection in evolutionary games on networks. Phys. Rev. E 114, 044301. Oct 1, 2026.

https://journals.aps.org/pre/abstract/10.1103/25qf-sfsw

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

Keywords: games, networks, collapse, transitions, Prisoner's Dilemma, defection, defection spreading-time, internode interactions, transient dynamics.

# life: 3-D microprinting anisotropic and deformable active matter.

<< ️Active colloidal particles are a versatile model system for exploring nonequilibrium physics in motile matter. To date, most experimental realizations have focused on spherical particles, largely due to fabrication constraints. However, theoretical and computational studies have long predicted that particle anisotropy and flexibility can dramatically enrich single-particle dynamics, interparticle interactions, and emergent collective behavior. >>

<< ️Here, (AA) highlight recent advances in the fabrication of anisotropic active particles and architectures enabled by the unprecedented design freedom of three-dimensional microprinting. (They) discuss how additive manufacturing is expanding the accessible parameter space of active soft matter, allowing precise control over shape, location of active forces, and functionality at the microscale. These advances enable the development of new model platforms for uncovering fundamental principles of active and soft matter, and simultaneously pave the way toward microrobotic systems with programmable dynamics and emergent functionalities. >>

Mengshi Wei, Daniela J. Kraft. Three-dimensional microprinting anisotropic and deformable active matter. Phys. Rev. E 114, 041001. Oct 2, 2026.

https://journals.aps.org/pre/abstract/10.1103/vvnp-l1sb

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

Keywords: gst, particles, motile matter, soft matter, active colloidal particles, three-dimensional microprinting, colloids, additive manufacturing.