# gst: like fireflies or neurons, dynamics of pulsating swarmalators on a ring.

AA << study a simple one-dimensional model of swarmalators, a generalization of phase oscillators that swarm around in space as well as synchronize internal oscillations in time. Previous studies of the model focused on Kuramoto-type couplings, where the phase interactions are governed by phase differences. >>

 Here AA << consider Winfree-type coupling, where the interactions are multiplicative, determined by the product of a phase response function  and phase pulse function . This more general interaction (from which the Kuramoto phase differences emerge after averaging) produces rich physics: six long-term modes of organization are found, which we characterize numerically and analytically. >>

Samali Ghosh, Kevin O'Keeffe, et al. Dynamics of pulsating swarmalators on a ring. arXiv: 2504.14912v1 [nlin.AO]. Apr 21, 2025. 

https://arxiv.org/abs/2504.14912

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

Keywords: gst, swarm, swarmalators, instability

# gst: transitions of breakup regimes for viscous droplets in airflow.

In this AA study, << the transitions of breakup regimes for viscous droplets are investigated experimentally using high-speed imaging taken from a side view and a 45 view. Based on the morphology change in the middle of the droplet, the breakup regimes are classified into no-breakup, bag breakup, bag-stamen, low-order multimode, high-order multimode, and shear-stripping breakup. The droplet morphologies in different regimes and the corresponding transitions are discussed in detail. >>

<< The droplet viscosity dissipates the kinetic energy transferred by the airflow during the initial droplet flattening, and affects the development of the Rayleigh-Taylor instability wave after the flattening. Through the analysis of the droplet deformation and the Rayleigh-Taylor instability with the droplet viscosity taken into account, the transition conditions of different regimes are obtained in a regime map. By further considering the relative velocity loss between the droplet and the airflow, the ranges of the dual-bag breakup in the low-order multimode regime and the droplet retraction in the bag-stamen regime are determined. >>

Zhikun Xu, Tianyou Wang, Zhizhao Che. Transitions of breakup regimes for viscous droplets in airflow. arXiv: 2504.14149v1 [physics.flu-dyn]. Apr 19, 2025.

https://arxiv.org/abs/2504.14149

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

Keywords: gst, drops, droplets, droploids, viscous droplets, droplet breakup, transitions, instability, waves

# gst: period-doubling route to chaos in viscoelastic flows

<< Polymer solutions can develop chaotic flows, even at low inertia. This purely elastic turbulence is well studied, but little is known about the transition to chaos. In two-dimensional (2D) channel flow and parallel shear flow, traveling wave solutions involving coherent structures are present for sufficiently large fluid elasticity. >>

AA << numerically study 2D periodic parallel shear flow in viscoelastic fluids, and (They) show that these traveling waves become oscillatory and undergo a series of period-doubling bifurcations en-route to chaos. >>

Jeffrey Nichols, Robert D. Guy, Becca Thomases. Period-doubling route to chaos in viscoelastic Kolmogorov flow. Phys. Rev. Fluids 10, L041301. Apr 17, 2025.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.10.L041301

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

Keywords: gst, chaos, waves, traveling waves, elasticity, viscoelastic fluids, turbulence, elastic turbulence, period-doubling bifurcations, transitions

# gst: apropos of migrations, asymmetric simple exclusion process with concerted hopping.

<< An important mechanism enabling fast ion diffusion in solid electrolytes is considered to be the significant lowering of the activation barrier when two or more ion particles hop simultaneously between sites, i.e., concerted migration, compared to single-ion hopping. >>

In this study AA << incorporate a mechanism of simultaneous particle hopping into the asymmetric simple exclusion process, which is an archetypal model for many-particle transportation phenomena, and investigate its impact on particle transport properties. >>

In Their model, << reflecting ion dynamics, the hopping rates are controlled by the activation energy, inverse temperature, and strength of an external driving field. (AA) first construct an exact solution that describes the steady state of the proposed model. By using this solution, (They) find that concerted migration substantially increases the particle current and induces a shift of the peak in the fundamental diagram, i.e., the density-current relationship. >>

AA << also show the presence of a critical temperature that maximizes the current. Additionally, we discuss the implications within parameter regions corresponding to actual materials. >>

Takahiro Ezaki, Kai Kihara, et al. Asymmetric simple exclusion process with concerted hopping. Phys. Rev. Research 7, 023068. Apr 21, 2025.

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.7.023068

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

Keywords: gst, particles, migration, asymmetric exclusion process, hopping, hopping rates

# gst: homology for structural characterization in disordered systems

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

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

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

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

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

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

Keywords: gst, particle, disorder, homology

# life: trace the rise and fall of inequality in China (over 5,000 years)

<< The rise and fall of inequality in the west has been studied in detail by eminent economists such as Simon Kuznets and Thomas Piketty. But China offers a chance to go much further back in time, having maintained a unified identity and unique language for more than 5,000 years – as well as some extraordinarily detailed dynastic archives. >>

<< Using these, a team of economists including the author of (Their) latest Insights long read, Peng Zhou from Cardiff University, set out to trace the impact of technological advances – from the revolutionary iron plough to block printing and imperial exams – on inequality in China’s imperial dynasties spanning two millennia. >>

<< Their conclusions have some fascinating implications for today’s technological panic over the rise of AI. As we stand at the edge of this latest technological cliff, history whispers: “Calm down. You’ve been here before.” >>

Mike Herd. The Daily. theconversation.com. UK Edition. Apr 25, 2025.

https://theconversationuk.cmail20.com/t/r-e-thdttlkt-ukutudjrtl-r/

Peng Zhou. What 2,000 years of Chinese history reveals about today’s AI-driven technology panic – and the future of inequality. theconversation.com. Apr 24, 2025.

https://theconversation.com/what-2-000-years-of-chinese-history-reveals-about-todays-ai-driven-technology-panic-and-the-future-of-inequality-254505

Also: Are you ready for all this?  in https://www.inkgmr.net/kwrds.html 

Keywords: life, oops, are you ready for all this

# gst: how noise affects memory in linear recurrent networks

<< The effects of noise on memory in a linear recurrent network are theoretically investigated. Memory is characterized by its ability to store previous inputs in its instantaneous state of network, which receives a correlated or uncorrelated noise. >>

<< Two major properties are revealed: First, the memory reduced by noise is uniquely determined by the noise's power spectral density (PSD). Second, the memory will not decrease regardless of noise intensity if the PSD is in a certain class of distribution (including power law). >>

JingChuan Guan, Tomoyuki Kubota, et al. How noise affects memory in linear recurrent networks. Phys. Rev. Research 7, 023049. Apr 14, 2025.

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.7.023049

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

Keywords: gst, noise, network, memory

# life: Trump-Musk, an evolution of the mjq model, one of the two attractors is a phantom entity

<< Elon Musk may be easing off his role at the Department of Government Efficiency (DOGE ), but President Donald Trump isn't easing off his praise. >>

<< On Wednesday, Trump praised Musk's smarts and patriotism during an executive order signing in the Oval Office, brushing off critics and defending the tech mogul’s work on federal reform. >>

<< "He’s an incredible… brilliant guy," Trump said. "He was a tremendous help both in the campaign, and in what he's done with DOGE." >>

<< DOGE, launched in 2025, has served as a hallmark of Trump’s second-term agenda to cut waste, streamline federal agencies, and apply private sector principles to federal operations. >>

Jasmine Baehr. Trump praises Elon Musk as ‘patriot, a brilliant guy, and a friend of mine’ amid DOGE exit. Foxnews.com. Apr23, 2025 10:43pm EDT.

https://www.foxnews.com/politics/trump-praises-elon-musk-patriot-brilliant-guy-friend-mine-amid-doge-exit

Also: mjq in Font https://flashontrack.blogspot.com/search?q=mjq 

mjq in Notes (quasi-stochastic poetry) attrattore cooperativo bipolare (nell' elastici spigoli). March 05, 2007.

https://inkpi.blogspot.com/2007/03/2124-attrattore-cooperativo-bipolare.html

Also: (Perpetual post-Donald, implemented in an artificial intelligence machine). Exponential post-Donald (without Donald), how AI could interfere (drive) next political elections. FonT. May 9, 2023.

https://flashontrack.blogspot.com/2023/05/life-exponential-post-donald-without.html

Also: Mr. Donald, artificial intell, jazz, in https://www.inkgmr.net/kwrds.html 

Keywords: life, mjq, jazz, Donald, ai, artificial intelligence

# gst: stochastic surfing turbulent vorticity.

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

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

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

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

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

https://arxiv.org/abs/2504.08346

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

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

# gst: statistical mechanics of frustrated assemblies and incompatible graphs

<< Geometrically frustrated assemblies where building blocks misfit have been shown to generate intriguing phenomena from self-limited growth, fiber formation, to structural complexity. >>  

AA << introduce a graph theory formulation of geometrically frustrated assemblies, capturing frustrated interactions through the concept of incompatible flows, providing a direct link between structural connectivity and frustration. This theory offers a minimal yet comprehensive framework for the fundamental statistical mechanics of frustrated assemblies, and connects it to tensor gauge theory formulations of amorphous solids. >>

<< Through numerical simulations, the theory reveals new characteristics of frustrated assemblies, including two distinct percolation transitions for structure and incompatible flows, a crossover between cumulative and noncumulative frustration controlled by disorder, and a divergent length scale in their response. >>

José M. Ortiz-Tavárez, Zhen Yang, et al. Statistical Mechanics of Frustrated Assemblies and Incompatible Graphs. Phys. Rev. Lett. 134, 147401. Apr 7, 2025. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.147401

arXiv: 2407.18210v1 [cond-mat.soft]. Thu, 25 Jul 2024.

https://arxiv.org/abs/2407.18210 

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

Keywords: gst, disorder, transitions, percolation transitions, frustration, frustrated assemblies 

# gst: strange attractors in complex networks

<< Disorder and noise in physical systems often disrupt spatial and temporal regularity, yet chaotic systems reveal how order can emerge from unpredictable behavior. Complex networks, spatial analogs of chaos, exhibit disordered, non-Euclidean architectures with hidden symmetries, hinting at spontaneous order. Finding low-dimensional embeddings that reveal network patterns and link them to dimensionality that governs universal behavior remains a fundamental open challenge, as it needs to bridge the gap between microscopic disorder and macroscopic regularities. >>

<< Here, the minimal space revealing key network properties is introduced, showing that non-integer dimensions produce chaotic-like attractors. >>

Pablo Villegas. Strange attractors in complex networks. Phys. Rev. E 111, L042301. Apr 15, 2025. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.L042301.  

arXiv: 2504.08629v1 [cond-mat.stat-mech] . Apr 11, 2025.

https://arxiv.org/abs/2504.08629

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

Keywords: gst, disorder, disorder & fluctuations, noise, networks, attractors, self-similarity, chaos 

# gst: weird quasiperiodic attractors

AA << consider a class of n-dimensional, n≥2, piecewise linear discontinuous maps that can exhibit a new type of attractor, called a weird quasiperiodic attractor. While the dynamics associated with these attractors may appear chaotic, (They)  prove that chaos cannot occur. The considered class of n-dimensional maps allows for any finite number of partitions, separated by various types of discontinuity sets. The key characteristic, beyond discontinuity, is that all functions defining the map have the same real fixed point. These maps cannot have hyperbolic cycles other than the fixed point itself. >>

Laura Gardini, Davide Radi, et al. Abundance of weird quasiperiodic attractors in piecewise linear discontinuous maps. arXiv: 2504.04778v1 [math.DS]. Apr 7, 2025.

https://arxiv.org/abs/2504.04778

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

Keywords: gst, attractors, weird attractors, chaos

# gst: elastic instability of wormlike micelle solution flow in serpentine channels

AA << investigated the flow behavior of a highly elastic, shear-thinning, semi-dilute (Wormlike micelle) WLM solution in serpentine channels at low Reynolds number and moderate Weissenberg numbers. >>

Their << flow visualization experiments revealed three key phenomena: >>

1. << At low Wi, the base flow is steady and laminar but exhibits spatial asymmetry with wall slip, reflecting the shear-thinning and shear banding properties of the WLM solution. Above a critical Wi (..) the flow undergoes an elastic instability and transitions to a 3D unsteady flow state characterized by pronounced spatiotemporal velocity fluctuations. (..). >>

2. << Alongside this unstable bulk flow, dead zones of stagnant fluid form in the downstream portion of halfloops—reflecting the ability of the WLM solution to support shear localization, complementing reports of dead zone formation for other types of complex fluids (..). Due to coupling to the velocity fluctuations in the bulk flow, these dead zones fluctuate in their size; however, they are bounded by a maximalsize that minimizes the fluid streamline curvature, and therefore the generation of elastic stresses. Dead zones also exhibit multistable behavior—forming and persisting in some half-loops, not forming in other half-loops, and randomly switching between these two states. (..). >>

3. << The unstable flow state also features intermittent, 3D “twisting” velocity inversion events amid the spatiotemporally-fluctuating bulk flow. These twisting events reduce the hydrodynamic tortuosity compared to the base flow state, and their geometric structure can also be rationalized as minimizing the fluid streamline curvature, and therefore the generation of elastic stresses. >>

Emily Y. Chen, Sujit S. Datta. Elastic instability of wormlike micelle solution flow in serpentine channels. arXiv: 2504.02951v1 [physics.flu-dyn]. 

https://arxiv.org/abs/2504.02951

Also: elastic, instability, disorder & fluctuations, transition, behav, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, elasticity, instability, disorder & fluctuations, transition, behavior, multistable behavior, randomly switch, twisting events, dead zone

# gst: apropos of drift-waves, their coherent puff and slugs in transitional turbulence.

<< The long-term development of the transitional regime of drift-wave turbulence is studied in a magnetized plasma column by means of the conditional-average technique. >>

<< In the transitional regime, small changes in the magnetic-field strength as control parameter lead to large changes in the correlation times, indicating the existence of a critical point of an underlying nonequilibrium continuous phase transition. >>

<< This and the spatiotemporal dynamics shows similarities to puff splitting, slug-gap splitting, and puff jamming. >>️

P. Manz, S. Knauer, et al. Coherent puff and slugs in transitional drift-wave turbulence. Phys. Rev. E 111, 045203. April 8, 2025.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.045203

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

Keywords: gst, waves, drift-waves, turbulence, jamming, transition, puff splitting, slug-gap splitting, puff jamming 

# gst: experimental investigation of turbulence modulation by deformable bubbles

<< In this work (AA) experimentally investigate the turbulence modulation in the wake of deforming bubbles in homogeneous and isotropic turbulence, in the regime where the turbulence fluctuation is stronger than or comparable to the bubble rising velocity. >>

<< In a quiescent or weak turbulence, the wake has a persistent direction due to the buoyancy. In turbulence, however, (Their) results suggest that the decorrelation time for the slip velocity roughly equals the bubble-sized eddy turn over time. It suggests that, when turbulence becomes intense enough, the slip velocity changes its direction and magnitude so frequently that a wake barely has time to develop. >>

<< As a result, both the intensity and length of the wake are significantly modified. Nevertheless, with sufficient bubble Reynolds number, the wake, albeit limited, can still modulate surrounding turbulence. >>

<< The results suggest that the local turbulence is augmented by the bubble wake, and the amount of augmentation depends heavily on the bubble Reynolds number, the orientation of the bubble semimajor axis relative to the slip velocity, and the bubble deformation. >>️

Xu Xu, Shiyong Tan, et al. Experimental investigation of turbulence modulation by deformable bubbles. Phys. Rev. Fluids 10, 033605. March 31, 2025.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.10.033605

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

Keywords: gst, bubble, deformable bubbles, bubble wake, bubble-bubble interaction, disorder & fluctuations, turbulence, turbulence modulation, surrounding turbulence, vortex, slip velocity, buoyancy

# gst: switching from active Brownian motion to stationary rotation of Janus particles in a viscoelastic fluid.

<< Swimming micro-objects exist in viscoelastic fluids. Elucidating the effect of viscoelasticity on the motion of these objects is important for understanding their behavior. >>

AA << examined the motion of Janus particles self-propelled by induced charge electrophoresis over a wide range of speeds in semidilute polymer solutions. In (Their) system, the motion of Janus particles changed from active Brownian motion to stationary rotation as the speed increased. The torque for stationary rotation originates from the difference between the direction of self-propulsion and that of the time-delayed restoring force from the polymer solution, which has been reported in another self-propelled particle system. The switch from active Brownian motion to stationary rotation at different polymer concentrations can be explained by the Weisenberg number, which is defined as the ratio of the relaxation time of the polymer network to the travel time of the Janus particle to its size. >>

Keita Saito, Ryunosuke Kawano, et al. Self-propelled motion of induced-charge electrophoretic Janus particles in viscoelastic fluids. Phys. Rev. E 111, 045409. Apr 10, 2025.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.045409

️

Also: Janus, transition, particle, in FonT:

Janus https://flashontrack.blogspot.com/search?q=janus 

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

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

Keywords: gst, Janus, transitions, particles, self-propelled particles

# gst: chaotic and time-periodic edge states in square duct flow.

AA << analyse the dynamics within the stability boundary between laminar and turbulent square duct flow with the aid of an edge-tracking algorithm. As for the circular pipe, the edge state turns out to be a chaotic attractor within the edge if the flow is not constrained to a symmetric subspace. The chaotic edge state dynamics is characterised by a sequence of alternating quiescent phases and regularly occurring bursting episodes. These latter reflect the different stages of the well-known streak-vortex interaction in near-wall turbulence: the edge states feature most of the time a single streak with a number of flanking quasi-streamwise vortices attached to one of the four surrounding walls. The initially straight streak undergoes the classical linear instability and eventually breaks in an intense bursting event due to the action of the quasi-streamwise vortices. At the same time, the vortices give rise to a new generation of low-speed streaks at one of the neighbouring walls, thereby causing the turbulent activity to `switch' from one wall to the other. >>

<< When restricting the edge dynamics to a single or twofold mirror-symmetric subspace, on the other hand, the outlined bursting and wall-switching episodes become self-recurrent in time. These edge states thus represent the first periodic orbits found in the square duct. In contrast to the chaotic edge states in the non-symmetric case, the imposed symmetries enforce analogue bursting cycles to simultaneously appear at two parallel opposing walls in a mirror-symmetric configuration. Both localisation of the turbulent activity to one or two walls and wall switching are shown to be a common phenomenon in low Reynolds number duct turbulence. (They) therefore argue that the marginally turbulent trajectories transiently visit the identified edge states during these episodes, so that the edge states become actively involved in the turbulent dynamics. >>️

Markus Scherer, Markus Uhlmann, Genta Kawahara. Chaotic and time-periodic edge states in square duct flow. arXiv: 2503.22519v1 [physics.flu-dyn]. Mar 28, 2025️. 

https://arxiv.org/abs/2503.22519

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

Keywords: gst, turbulence, duct turbulence, chaos, chaotic edge states, vortex, instability, wall-switching episodes, bursting cycles 

# gst: apropos of odd droplets; fluids with broken symmetries could self-control their mechanics.

<< Flows with deformable interfaces are commonly controlled by applying an external field or modifying the boundaries that interact with the fluid, (..) Here, (AA) demonstrate that fluids with broken symmetries can self-control their mechanics. (They) demonstrate that odd viscosity dramatically disrupts conventional symmetric spreading by inducing asymmetric deformations and chiral flow patterns. (Their) analysis reveals a variety of dynamic regimes, including leftward and rightward bouncing, as well as rolling, depending on the relative strength of the odd viscosity. >>️

Hugo França, Maziyar Jalaal. Odd Droplets: Fluids with Odd Viscosity and Highly Deformable Interfaces. arXiv: 2503.21649v1 [cond-mat.soft]. Mar 27, 2025.

https://arxiv.org/abs/2503.21649

Also: drop, droplet, droploid, chiral, bouncing, rolling, slipping, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, drop, droplet, droploid, chirality, bouncing, rolling, slipping, oddity, odd viscosity, self-control

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

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

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

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

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

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

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

Keywords: gst, particle, turbulence, disorder, fluctuations

# gst: conventional and anomalous mobility edges in a quasiperiodic chain.

<< Mobility edges (MEs) constitute the energies separating the localized states from the extended ones in disordered systems. Going beyond this conventional definition, recent proposal suggests for an ME which separates the localized and multifractal states in certain quasiperiodic systems - dubbed as the anomalous mobility edges (AMEs). >>

<< In this study, (AA) propose an exactly solvable quasiperiodic system that hosts both the conventional and anomalous mobility edges under proper conditions. (They) show that with increase in quasiperiodic disorder strength, the system first undergoes a delocalization to localization transition through an ME of conventional type. >>

<< Surprisingly, with further increase in disorder, (They) obtain that a major fraction of the localized states at the middle of the spectrum turn multifractal in nature. Such unconventional behavior in the spectrum results in two AMEs, which continue to exist even for stronger quasiperiodic disorder. >>

AA << numerically obtain the signatures of the coexisting MEs complement it through analytical derivation using Avila's global theory. In the end (They) provide important signatures from the wavepacket dynamics. >>️

Sanchayan Banerjee, Soumya Ranjan Padhi, Tapan Mishra. Emergence of distinct exact mobility edges in a quasiperiodic chain. arXiv: 2503.19834v1 [cond-mat.quant-gas]. Mar 25, 2025.️

https://arxiv.org/abs/2503.19834

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

Keywords: gst, edge, order, disorder, waves, transition 

# gst: apropos of bubble rearrangements, transition from slip to scraping as critical-like behavior in foam dynamics.

<< Jamming systems, including colloids, emulsions, foams, and biological tissues, undergo significant deformation during processes like material scraping or wound self-healing. To adequately spread a foam or cream over a surface, external force must be applied to artificially scrape it. Notably, the transition from slip to scraping when foam is manipulated using a rigid plate remains poorly understood. >>

<< Systematic observations of the internal foam structure during scraping were conducted, and the scraping length was qualitatively analyzed by varying the scraping velocity. (AA) study reveals that the transition from slip to scraping is driven by the sequential propagation of bubble rearrangements. Furthermore, the scraping length diverges towards the transition point, with a critical exponent of approximately 0.61. >>

<< These findings align with directional percolation theory, underscoring the robustness of the theoretical framework. >>

Masaya Endo, Rei Kurita. Critical-like behavior in foam dynamics: Transition from slip to scraping. Phys. Rev. Research 7, 023013. Apr 3, 2025.

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.7.023013

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

Keywords: gst, bubble, bubble rearrangements, foam, jamming, transition, criticality, scraping,  percolation

# life: detecting hallucinations (in large language models) using semantic entropy.

<< Large language model (LLM) systems, such as ChatGPT or Gemini, can show impressive reasoning and question-answering capabilities but often ‘hallucinate’ false outputs and unsubstantiated answers. >>

<< Here (AA) develop new methods grounded in statistics, proposing entropy-based uncertainty estimators for LLMs to detect a subset of hallucinations— confabulations— which are arbitrary and incorrect generations. (Their) method addresses the fact that one idea can be expressed in many ways by computing uncertainty at the level of meaning rather than specific sequences of words. >>

Their method << works across datasets and tasks without a priori knowledge of the task, requires no task-specific data and robustly generalizes to new tasks not seen before. By detecting when a prompt is likely to produce a confabulation, helps users understand when they must take extra care with LLMs and opens up new possibilities for using LLMs that are otherwise prevented by their unreliability. >>️️

Sebastian Farquhar, Jannik Kossen, et al. Detecting hallucinations in large language models using semantic entropy. Nature 630, 625–630. Jun 19, 2024.

https://www.nature.com/articles/s41586-024-07421-0

Also: ai (artificial intell) (bot), entropy, in https://www.inkgmr.net/kwrds.html 

Keywords: life, artificial intelligence,  LLMs, confabulations, uncertainty, hallucinations, entropy, semantic entropy

# gst: asymptotic scaling in a one-dimensional billiard

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

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

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

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

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

https://arxiv.org/abs/2503.20476

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

Keywords: gst, billiard, randomness 

# gst: evolution of robust cell differentiation mechanisms under epigenetic feedback

<< In multi-cellular organisms, cells differentiate into multiple types as they divide. States of these cell types, as well as their numbers, are known to be robust to external perturbations; as conceptualized by Waddington's epigenetic landscape where cells embed themselves in valleys corresponding with final cell types. >>

<< How is such robustness achieved by developmental dynamics and evolution? To address this question, (AA) consider a model of cells with gene expression dynamics and epigenetic feedback, governed by a gene regulation network. By evolving the network to achieve more cell types, (They) identified three major differentiation mechanisms exhibiting different properties regarding their variance, attractors, stability, and robustness. >>

<< The first of these mechanisms, type A, exhibits chaos and long-lived oscillatory dynamics that slowly transition until reaching a steady state. The second, type B, follows a channeled annealing process where the epigenetic changes in combination with noise shift the stable landscape of the cells towards varying final cell states. Lastly, type C exhibits a quenching process where cell fate is quickly decided by falling into pre-existing fixed points while cell trajectories are separated through periodic attractors or saddle points. >>

AA << find types A and B to correspond well with Waddington's landscape while being robust. Finally, the dynamics of type B demonstrate a novel method through dimensional reduction of gene-expression states during differentiation. >>

Davey Plugers, Kunihiko Kaneko. Evolution of robust cell differentiation mechanisms under epigenetic feedback. arXiv: 2503.20651v1 [physics.bio-ph]. Mar 26, 2025. 

https://arxiv.org/abs/2503.20651

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

Keywords: gst, evolution, noise, epigenetics, epigenetic feedback, differentiation

# gst: when a phase transition could be controlled by a fixed point of infinite disorder

AA << apply a real-space block renormalization group approach to study the critical properties of the random transverse-field Ising spin chain with multispin interactions. First (They) recover the known properties of the traditional model with two-spin interactions by applying the renormalization approach for arbitrary size of the block. For the model with three-spin couplings (They) calculate the critical point and demonstrate that the phase transition is controlled by an infinite disorder fixed point. (AA) have determined the typical correlation-length critical exponent, which seems to be different from that of the random transverse Ising chain with nearest-neighbor couplings. Thus this model represents a new infinite disorder universality class. >>️

Ferenc Iglói, Yu-Cheng Lin. Random quantum Ising model with three-spin couplings. arXiv:2503.18690v1 [cond-mat.dis-nn]. Mar 24, 2025.

https://arxiv.org/abs/2503.18690

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

Keywords: gst, disorder, order, transition

# life: and so the short run matters, by John.

<<  Good Wednesday morning, and happy Liberation Day. This is Jack Blanchard, off to panic-buy Yorkshire Tea and Scotch whisky before the tariffs kick in.  >>️

<<  Fears on the Hill: In particular, the numerous free-traders in the GOP’s ranks on the Hill are feeling pretty darn uncomfortable about what’s coming. Sen. John Kennedy (R-La.) said he hopes the president’s plan is ultimately to use the threat of tariffs to force other nations to strip back their own. “In the long run, [it] will probably work,” he said. “The problem is that in the long run, we’re all dead. And so the short run matters.”  >>

Jack Blanchard. A message to Musk. Politico. Playbook. Apr 02, 2025. 

https://www.politico.com/newsletters/playbook/2025/04/02/a-message-to-musk-00265583  

Also: Mr. Donald, Mr. Vlad, Mr. Chen, RAG-time, triptych, crack, in https://www.inkgmr.net/kwrds.html 

Keywords: life, Mr. Donald, Mr. Vlad, Mr. Chen, RAG-time, triptych, crack

# epidem: societal self-regulation appears to induce complex infection dynamics and chaos.

<< Classically, endemic infectious diseases are expected to display relatively stable, predictable infection dynamics. Accordingly, basic disease models such as the susceptible-infected-recovered-susceptible model display stable endemic states or recurrent seasonal waves. However, if the human population reacts to high infection numbers by mitigating the spread of the disease, then this delayed behavioral feedback loop can generate infection waves itself, driven by periodic mitigation and subsequent relaxation. >>

AA << show that such behavioral reactions, together with a seasonal effect of comparable impact, can cause complex and unpredictable infection dynamics, including Arnold tongues, coexisting attractors, and chaos. >>

<< Importantly, these arise in epidemiologically relevant parameter regions where the costs associated to infections and mitigation are jointly minimized. By comparing (Their) model to data, (AA) find signs that COVID-19 was mitigated in a way that favored complex infection dynamics. (AA)  results challenge the intuition that endemic disease dynamics necessarily implies predictability and seasonal waves and show the emergence of complex infection dynamics when humans optimize their reaction to increasing infection numbers. >>️

Joel Wagner, Simon Bauer, et al.  Societal self-regulation induces complex infection dynamics and chaos. Phys. Rev. Research 7, 013308. Mar 24, 2025.

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.7.013308

Also: virus, sars* covid* (aka 1or2achoos), waves, chaos, in https://www.inkgmr.net/kwrds.html 

Keywords: epidemiology, virus, sars, covid-19, chaos

# gst: synchronization and chaos in complex systems with delayed interactions.

<< Explaining the wide range of dynamics observed in ecological communities is challenging due to the large number of species involved, the complex network of interactions among them, and the influence of multiple environmental variables. >>

AA << consider a general framework to model the dynamics of species-rich communities under the effects of external environmental factors, showing that it naturally leads to delayed interactions between species, and analyze the impact of such memory effects on population dynamics. >>

<< Employing the generalized Lotka-Volterra equations with time delays and random interactions, (AA) characterize the resulting dynamical phases in terms of the statistical properties of community interactions. (Their) findings reveal that memory effects can generate persistent and synchronized oscillations in species abundances in sufficiently competitive communities. This provides an additional explanation for synchronization in large communities, complementing known mechanisms such as predator-prey cycles and environmental periodic variability. >>

<< Furthermore, (AA) show that when reciprocal interactions are negatively correlated, time delays alone can induce chaotic behavior. This suggests that ecological complexity is not a prerequisite for unpredictable population dynamics, as intrinsic memory effects are sufficient to generate long-term fluctuations in species abundances. >>

Francesco Ferraro, Christian Grilletta, et al. Synchronization and chaos in complex ecological communities with delayed interactions. arXiv: 2503.21551v1 [q-bio.PE]. Mar 27, 2025.

https://arxiv.org/abs/2503.21551

Also: pause, silence, random, chaos, network, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, pause, silence, random, chaos, chaotic behavior, network, delay, time delay, delayed interactions, random interactions, memory effect 

# gst: apropos of multiple delays, transitions to intermittent chaos in quorum sensing-inspired dynamics.

<< This study analyses the dynamical consequences of heterogeneous temporal delays within a quorum sensing-inspired (QS-inspired) system, specifically addressing the differential response kinetics of two subpopulations to signalling molecules. >>️

<< The analysis reveals the critical role of multiple, dissimilar delays in modulating system dynamics and inducing bifurcations. Numerical simulations, conducted in conjunction with analytical results, reveal the emergence of periodic self-sustained oscillations and intermittent chaotic behaviour. These observations emphasise the intricate relationship between temporal heterogeneity and the stability landscape of systems exhibiting QS-inspired dynamics. This interplay highlights the capacity for temporal variations to induce complex dynamical transitions within such systems. >>️

AA << findings show that the presence of multiple delays, particularly when characterised by significant disparities in magnitude, can dramatically alter the system’s stability features and promote the emergence of complex nonlinear oscillatory behaviour. >>️

<< Upon explicitly incorporating distinct delays for different state-components, (AA) have shown how temporal factors can dramatically influence system stability and give rise to a spectrum of complex dynamical behaviours, including intermittent chaos. >>

Anahí Flores, Marcos A. González, Víctor F. Breña-Medina. Transitions to Intermittent Chaos in Quorum Sensing Dynamics. arXiv: 2503.14363v2 [nlin.CD]. Mar 19, 2025.

https://arxiv.org/abs/2503.14363

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

Keywords: gst, intermittency, pause, silence, transitions, chaos 

# gst: noise as endogenous control

<< Systems biology faces the monumental task of synthesizing vast amounts of molecular facts into a cohesive whole. While it is recognized that stochasticity is ubiquitous in the cell, with noise playing a role in gene expression, differentiation, and switching (..), it is still commonly argued that the cell functions in spite of the noisy cellular environment. >>️

<< Stochastic systems have a control-theoretic interpretation in which noise plays the role of endogenous control. In the weak-noise limit, relevant at low temperatures or in large populations, control is optimal and an exact mathematical mapping from noise to control is described, where the maximizing the probability of a state becomes the control objective. >>

<< In Langevin dynamics noise is identified directly with control, while in general Markov jump processes, which include chemical reaction networks and electronic circuits, (AA) use the Doi-Zel'dovich-Grassberger-Goldenfeld-Peliti path integral to identify the `response' or `tilt' field π as control, which is proportional to the noise in the semiclassical limit. This solves the longstanding problem of interpreting π. >>

AA << illustrate the mapping on multistable chemical reaction networks and systems with unstable fixed points. The noise-control mapping builds intuition for otherwise puzzling phenomena of stochastic systems: why the probability is generically a non-smooth function of state out of thermal equilibrium; why biological mechanisms can work better in the presence of noise; and how agentic behavior emerges naturally without recourse to mysticism. >>

Eric De Giuli. Noise equals endogenous control. arXiv: 2503.15670v2 [q-bio.MN]. Mar 24, 2025.

https://arxiv.org/abs/2503.15670

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

Keywords: gst, noise, disorder, transition, ethno, crosstalk, gossip, misinformation, fake news, dance, jazz

# gst: odd electrical circuits

<< Non-reciprocal interactions in elastic media give rise to rich non-equilibrium behaviors, but controllable experimental realizations of such odd elastic phenomena remain scarce. Building on recent breakthroughs in electrical analogs of non-Hermitian solid-state systems, (AA) design and analyze scalable odd electrical circuits (OECs) as exact analogs of an odd solid. >>

AA << show that electrical work can be extracted from OECs via cyclic excitations and trace the apparent energy gain back to active circuit elements. (They) show that OECs host oscillatory modes that resemble recent experimental observations in living chiral crystals and identify active resonances that reveal a perspective on odd elasticity as a mechanism for mechanical amplification. >>️

Harry Walden, Alexander Stegmaier, et al. Odd electrical circuits. arXiv: 2503.14383v1 [cond-mat.soft]. Mar 18, 2025.

https://arxiv.org/abs/2503.14383

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

Keywords: gst, chirality, chiral crystals, chiral oscillations, chiral waves, oddity, odd elastic materials

# gst: droplet bag formation in turbulent airflows.

AA << present numerical simulations investigating the evolution of liquid droplets into baglike structures in turbulent airflows. The droplet bag breakup problem is of significance for many multiphase processes in scientific and engineering applications. Turbulent fluctuations are introduced synthetically into a mean flow, and the droplet is inserted when the air-phase turbulence reaches a statistically stationary state. The morphological evolution of the droplet under different turbulence configurations is retrieved and analyzed in comparison with laminar aerobreakup results. While the detailed evolution history of individual droplets varies widely between different realizations of the turbulent flow, common dynamic and morphological evolution patterns are observed. >>

<< The presence of turbulence is found to enhance the drag coefficient of the droplet as it flattens. At late times, the droplet becomes tilted and increasingly corrugated under strong turbulence intensity. (AA) quantify these phenomena and discuss their possible governing mechanisms associated with turbulence intermittency. >>

<< Lastly, the influences of liquid-gas viscosity ratio are examined and the implications of air-phase turbulence on the later bag film breakup process are discussed. >>️

Kaitao Tang, Thomas A. A. Adcock, Wouter Mostert. Droplet bag formation in turbulent airflows. Phys. Rev. Fluids 10, 033604. March 19, 2025.

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.10.033604

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

Keywords: gst, drop, droplet, droploid, turbulence, fluctuations, intermittency

# gst: from alternating stripes to alternating labyrinths, the Belousov−Zhabotinsky transition

<< Alternating (temporally period-2) stripes and labyrinths have been observed in media of chemical and biochemical reactions; however, the mechanisms underlying the formation of these spatiotemporal patterns remain unclear. >>

AA << conduct computer simulation using a modified model of Belousov−Zhabotinsky reaction that incorporates a global feedback loop with a spatial strength profile of Gaussian distribution. The simulation results demonstrate that the transition from alternating stripes to alternating labyrinths occurs when the feedback is negative with a certain width of the Gaussian function. (AA) add the same Gaussian-weighted feedback loop to an amplitude equation to describe the amplitude dynamics of the period-2 oscillation and show that the pattern dynamics of the Belousov−Zhabotinsky reaction can be well captured by this amplitude equation. >>

<< Analyses of the amplitude equation demonstrate that the transition from stripes to labyrinths arises from the transverse instabilities of bistable fronts caused by the Gaussian-weighted negative global feedback. >>️

Chunli Huang, Zhen Song, Zhilin Qu. Transition from alternating stripes to alternating labyrinths in oscillatory media. Phys. Rev. E 111, L032201. Mar 13, 2025.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.L032201

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

Also: Orologio chimico. Notes (quasi-stochastic poetry). Apr 08, 2005.

https://inkpi.blogspot.com/2005/04/1558-orologio-chimico.html  

Keywords: gst, transitions, BZ reaction, labyrinths, alternating labyrinths

# gst: First-passage-time statistics of active Brownian particles: a perturbative approach.

AA << study the first-passage-time (FPT) properties of active Brownian particles to reach an absorbing wall in two dimensions. Employing a perturbation approach (They) obtain exact analytical predictions for the survival and FPT distributions for small Péclet numbers, measuring the importance of self-propulsion relative to diffusion. >>

<< While randomly oriented active agents reach the wall faster than their passive counterpart, their initial orientation plays a crucial role in the FPT statistics. Using the median as a metric, (AA) quantify this anisotropy and find that it becomes more pronounced at distances where persistent active motion starts to dominate diffusion. >>️

Yanis Baouche, Magali Le Goff, et al. First-passage-time statistics of active Brownian particles: a perturbative approach. arXiv: 2503.05401v1 [cond-mat.soft]. Mar 7, 2025.

https://arxiv.org/abs/2503.05401

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

Keywords: gst, particles, active particles, perturbation approach, randomness, stochasticity, stochastic resetting, rotational diffusion, anisotropy

# poe: onda di gioco

<<  

Nota a far mescole coll' endogeno docile avo melode /

declamando su traccia nevale di dondolio di geco /

l' evento d' onde nella forma di compressa logica ode /

che, se liberata, s' autoespande in frange d' agile eco.

>>

14.31 13/09/2004

'solebat quid esset litus ita definire: "qua fluctus eluderet"'. In: Cicerone. 'de natura deorum'.

https://inkpi.blogspot.com/2005/03/1782-onda-di-gioco.html  

Anche:  waves, in   

Notes (quasi-stochastic poetry)  https://inkpi.blogspot.com/search?q=onda 

FonT  https://flashontrack.blogspot.com/search?q=waves 

inkgmr.net  https://www.inkgmr.net/kwrds.html 

Anche: World Poetry Day, in

 https://en.m.wikipedia.org/wiki/World_Poetry_Day     https://nationaltoday.com/world-poetry-day

Keywords: poe, poetry, quasi-stochastic poetry, PoetryDay, WorldPoetryDay, InternationalPoetryDay, waves, rogue waves, shock waves, solitons, turbulence, instability

# aibot: I think, therefore I hallucinate: minds, machines, and the art of being wrong.

<< This theoretical work examines 'hallucinations' in both human cognition and large language models, comparing how each system can produce perceptions or outputs that deviate from reality. Drawing on neuroscience and machine learning research, (AA) highlight the predictive processes that underlie human and artificial thought. >>

<< In humans, complex neural mechanisms interpret sensory information under uncertainty, sometimes filling in gaps and creating false perceptions. This inference occurs hierarchically: higher cortical levels send top-down predictions to lower-level regions, while mismatches (prediction errors) propagate upward to refine the model. LLMs, in contrast, rely on auto-regressive modeling of text and can generate erroneous statements in the absence of robust grounding. >>

<< Despite these different foundations - biological versus computational - the similarities in their predictive architectures help explain why hallucinations occur. (AA) propose that the propensity to generate incorrect or confabulated responses may be an inherent feature of advanced intelligence. In both humans and AI, adaptive predictive processes aim to make sense of incomplete information and anticipate future states, fostering creativity and flexibility, but also introducing the risk of errors. (Their) analysis illuminates how factors such as feedback, grounding, and error correction affect the likelihood of 'being wrong' in each system. (AA) suggest that mitigating AI hallucinations (e.g., through improved training, post-processing, or knowledge-grounding methods) may also shed light on human cognitive processes, revealing how error-prone predictions can be harnessed for innovation without compromising reliability. By exploring these converging and divergent mechanisms, the paper underscores the broader implications for advancing both AI reliability and scientific understanding of human thought. >>️

Sebastian Barros. I Think, Therefore I Hallucinate: Minds, Machines, and the Art of Being Wrong. arXiv: 2503.05806v1 [q-bio.NC]. 4 Mar 4, 2025.

https://arxiv.org/abs/2503.05806

Also: brain, curiosity, novelty, uncertainty, error, mistake, jazz, ai (artificial intell), in https://www.inkgmr.net/kwrds.html 

Keywords: brain, cognition, perceptions, curiosity, novelty, hallucinations, errors, prediction, prediction errors, error-prone predictions, AI, artificial intelligence, LLMs

# behav: the benefit of ignorance for traffic through a random congestible network.

<< When traffic is routed through a network that is susceptible to congestion, the self-interested decisions made by individual users do not, in general, produce the optimal flow. This discrepancy is quantified by the so-called "price of anarchy." >>

AA << consider whether the traffic produced by self-interested users is made better or worse when users have uncertain knowledge about the cost functions of the links in the network, and define a parallel concept that (They) call the "price of ignorance."  >>

AA << introduce a simple model in which fast, congestible links and slow, incongestible links are mixed randomly in a large network and users plan their routes with finite uncertainty about which of the two cost functions describes each link. >>

<< One of (Their) key findings is that a small level of user ignorance universally improves traffic, regardless of the network composition. Further, there is an optimal level of ignorance which, in (the) model, causes the self-interested user behavior to coincide with the optimum. Many features of (AA) model can be understood analytically, including the optimal level of user ignorance and the existence of critical scaling near the percolation threshold for fast links, where the potential benefit of user ignorance is greatest. >>️

Alican Saray, Calvin Pozderac, et al. The benefit of ignorance for traffic through a random congestible network. arXiv: 2503.09684v1 [cond-mat.dis-nn]. Mar 12, 2025.

https://arxiv.org/abs/2503.09684

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

Keywords: gst, networks, behavior,  randomness, uncertainty, price of anarchy, price of ignorance

# qubit: stability of classical shadows under gate-dependent noise

<< Expectation values of observables are routinely estimated using so-called classical shadows—the outcomes of randomized bases measurements on a repeatedly prepared quantum state. In order to trust the accuracy of shadow estimation in practice, it is crucial to understand the behavior of the estimators under realistic noise. >>

<< In this Letter, (AA) prove that any shadow estimation protocol involving Clifford unitaries is stable under gate-dependent noise for observables with bounded stabilizer norm—originally introduced in the context of simulating Clifford circuits. In contrast, (They) demonstrate with concrete examples that estimation of “magic” observables can lead to highly misleading results in the presence of miscalibration errors and a worst case bias scaling exponentially in the system size. >>

AA << further find that so-called robust shadows, aiming at mitigating noise, can introduce a large bias in the presence of gate-dependent noise compared to unmitigated classical shadows. Nevertheless, (AA) guarantee the functioning of robust shadows for a more general noise setting than in previous works. On a technical level, (They) identify average noise channels that affect shadow estimators and allow for a more fine-grained control of noise-induced biases. >>️

Raphael Brieger, Markus Heinrich, et al. Stability of Classical Shadows under Gate-Dependent Noise. Phys. Rev. Lett. 134, 090801. Mar 4, 2025. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.090801  arXiv: 2310.19947v3 [quant-ph]. Feb 19, 2025.   https://arxiv.org/abs/2310.19947

Also: qubit, in FonT  https://flashontrack.blogspot.com/search?q=qubit  noise, ai (artificial intell) (bot), in https://www.inkgmr.net/kwrds.html   

Keywords: qubit, noise, realistic noise, shadows, robust shadows

# gst: apropos of degeneration, the topological degeneracy induced by twisting.

<< In recent years, twisting has emerged as a new degree of freedom that plays an increasingly important role in Bloch bands of various physical systems. However, there is currently a lack of reports on the nontrivial physics of topological degeneracy in twisted systems. >>

AA << investigated the intrinsic physical correlation between twisting and topological degeneracy. (They) found that twisting not only breaks the symmetry of the system but also introduces topological degeneracy that does not exist under the original symmetric system without twisting. >>

<< Furthermore, the topological degeneracy can be easily tuned through twisting. This new twist-induced topological degeneracy gives rise to a unique polarization-degenerate birefringent medium, wherein the twist angle acts as a novel degree of freedom for dispersion and polarization management of interface states. >> 

<< Exhibiting fascinating properties and experimental feasibilities, (AA) Letter points to new possibilities in the research of various topological physics in twisted photonics. >>️

Han Peng, Qiang Wang, et al. Topological degeneracy induced by twisting. Phys. Rev. Lett. 134, 106601. Mar 11, 2025.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.106601   arXiv: 2503.09048v1 [physics.optics]. https://arxiv.org/abs/2503.09048  

Also: degeneration, in FonT https://flashontrack.blogspot.com/search?q=degeneration   twisting, twist, in FonT   https://flashontrack.blogspot.com/search?q=twisting    https://flashontrack.blogspot.com/search?q=twist 

Keywords: gst, degeneration, twisting 

# qubit: communication power of a noisy qubit.

<< A fundamental limitation of quantum communication is that a single qubit can carry at most one bit of classical information. For an important class of quantum communication channels, known as entanglement breaking, this limitation holds even if the sender and receiver share entangled particles. But does this mean that, for the purpose of communicating classical messages, a noisy entanglement-breaking qubit channel can be replaced by a noisy bit channel? >>

Here AA << answer the question in the negative. (They) introduce a game, similar to the Monty Hall problem in classical statistics, where a sender assists a receiver in finding a valuable item (the “prize”) hidden in one of four possible boxes, while avoiding a hazardous item (the “bomb”) hidden in one of the remaining three boxes. (AA) show that no classical strategy using a noisy bit channel can ensure that the bomb is avoided, even if the sender and receiver share arbitrary amounts of randomness. >>

<< In contrast, communication of a qubit through a class of noisy entanglement-breaking channels, which (They) call quantum not channels, allows the players to deterministically avoid the bomb and to find the prize with a guaranteed nonzero probability. >>

AA << findings show that the communication of classical messages through a noisy entanglement-breaking qubit channel assisted by quantum entanglement cannot, in general, be simulated by communication through a noisy bit channel assisted by classical correlations. >>️

Giulio Chiribella, Saptarshi Roy, et al. Communication Power of a Noisy Qubit. Phys. Rev. Lett. 134, 080803. Feb 28, 2025. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.080803     arXiv: 2405.17946v2 [quant-ph]. https://arxiv.org/abs/2405.17946  

Also: qubit, in https://flashontrack.blogspot.com/search?q=qubit  game, in  https://flashontrack.blogspot.com/search?q=game  noise, in  https://flashontrack.blogspot.com/search?q=noise 

Keywords: qubit, games, noise

# gst: dynamics of fluid-driven fractures across material heterogeneities.

<< Fracture propagation is highly sensitive to the conditions at the crack tip. In heterogeneous materials, microscale obstacles can cause propagation instabilities. Macroscopic heterogeneities modify the stress field over scales larger than the tip region. >>

 Here AA << experimentally investigate the propagation of fluid-driven fractures through multilayered materials. (They) focus on analyzing fracture profiles formed upon injection of a low-viscosity fluid into a two-layer hydrogel block. >>

<< Experimental observations highlight the influence of the originating layer on fracture dynamics. Fractures that form in the softer layer are confined, with no penetration in the stiffer layer. Conversely, fractures initiated within the stiffer layer experience rapid fluid transfer into the softer layer when reaching the interface. >>

AA << report the propagation dynamics and show that it is controlled by the toughness contrast between neighboring layers, which drives fluid flow. (They) model the coupling between elastic deformation, material toughness, and volume conservation. After a short transient regime, scaling arguments capture the dependence of the fracture geometry on material properties, injection parameters, and time. These results show that stiffness contrast can modify fracture propagation over large length scales and demonstrate the importance of macroscopic scale heterogeneities on fracture dynamics. >>

Sri Savya Tanikella, Marie C. Sigallon, Emilie Dressaire. Dynamics of fluid-driven fractures across material heterogeneities. Phys. Rev. E 111, 025504. Feb 28, 2025.   https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.025504     arXiv: 2407.10298v1 [physics.flu-dyn]. Jul 14, 2024.  https://arxiv.org/abs/2407.10298

Also: fracture, crack, elastic, 

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

Keywords: gst, fracture, crack, elasticity, instability, disorder, transitions

# gst: tandem droplets accelerated by continuous uniform airflow.

<< In a dense droplet environment, droplets influence each other's motion, deformation, and breakup behavior. The tandem droplet is a particularly relevant case for the study of its unsteady dynamic behavior. >>

<< A three-dimensional numerical simulation study was conducted to investigate the deformation process of tandem droplets under different conditions. >>

<< The results of the research show that under conditions of high density ratio and a significant Reynolds number, the edge morphological characteristics of droplets are predominantly influenced by the Rayleigh-Taylor instability. In the case of low density ratios, the pressure drag force on the leeward side exerts a dominant influence on the accelerated motion of the leading droplet. The shape of the droplet is significantly influenced by the vortex ring present in the recirculation region. The perturbation of the liquid edge induces the vortex ring to split into secondary vortex rings, which act back on the droplet, thereby affecting its morphological characteristics. The trailing droplet is subject to a reduction in cross-flow radius, drag coefficient, minimum length, and expansion speed of the liquid bag due to the influence of the wake of the leading droplet. The decrease in Reynolds number and relative distance leads to a stronger suppression effect, while the decrease in density ratio shortens the length of the recirculation region, thereby weakening the suppression of trailing droplets. >>

Shuting Peng, Fuzhen Chen, et al. Three-dimensional numerical simulation of tandem droplets accelerated by continuous uniform airflow. Phys. Rev. Fluids 10, 024304. Feb 25, 2025. 

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.10.024304  

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

Keywords: gst, droplet, instability, vortex, behavior

# gst: emergent flocking in mixtures of antialigning self-propelled particles.

FIG. 4. (c) Mean field phase diagram with disorder (green triangles), polarized moving bands (blue circles), and polarized patches (orange squares).

AA << observe a flocking mechanism, the emergence of a state with global polar order, in mixed systems of self-propelled particles with purely antialigning interactions, i.e., the ground state for any pair of particles is to be opposedly oriented. In binary mixtures, (They) find that flocking can be realized by cross-species antialigning that is dominant compared to intraspecies antialignment. >>

<< While the key mechanism can be understood within a mean-field description, beyond mean-field (AA) develop an asymptotically exact Boltzmann-scattering theory from first principles.  This theory yields analytical predictions for the flocking transition and shows excellent quantitative agreement with simulations of dilute systems. For large systems, (They) find either microphase separation or static patterns with patches or stripes that carry different polarization orientations. >>️

Rüdiger Kürsten, Jakob Mihatsch, Thomas Ihle. Emergent flocking in mixtures of antialigning self-propelled particles. Phys. Rev. E 111, L023402. Feb 21, 2025.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.111.L023402

Also: particle, flock, flocking, swarm, order, disorder, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, self-propelled particles, flock, flocking, swarm, order, disorder, transitions

# gst: 'jazzy' intermittency, its onset and multiscaling in active turbulence.

<< Recent results suggest that highly active, chaotic, nonequilibrium states of living fluids might share much in common with high Reynolds number, inertial turbulence. (AA) now show, by using a hydrodynamical model, the onset of intermittency and the consequent multiscaling of Eulerian and Lagrangian structure functions as a function of the bacterial activity. (Their) results bridge the worlds of low and high Reynolds number flows as well as open up intriguing possibilities of what makes flows intermittent. >>️

AA << believe that (Their) work significantly understands the dynamics of dense bacterial suspensions in ways which isolates the truly turbulent effects from those stemming from simpler chaotic motion. More intriguingly, and at a broader conceptual framework, this study yet again underlines that intermittency can be an emergent phenomena in flows where the nonlinearity does not, trivially, dominate the viscous damping. Indeed, there is increasing evidence of intermittency emerging in systems which are not turbulent in the classical sense. Examples include flows with modest Reynolds number of∼O(10e2) showing intermittent behaviour characteristic of high Reynolds turbulence, self-propelling active droplets with intermittent fluctuations, active matter systems of self-propelled particles, which undergo a glass transition, with an intermittent phase before dynamical arrest, and perhaps most pertinently, in elastic turbulence. Thus, (AA) believe, (Their) work will contribute further to understanding what causes flows to turn intermittent. Answers to such questions will also help in understanding fundamental questions in high Reynolds number turbulence. >>️

Kolluru Venkata Kiran, Kunal Kumar, et al. Onset of Intermittency and Multiscaling in Active Turbulence. Phys. Rev. Lett. 134, 088302. Feb 28, 2025. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.088302  arXiv: 2408.06950v2 [cond-mat.soft].  https://arxiv.org/abs/2408.06950

Also: intermittency, transition, fluctuations, drop, droplet, droploid, elastic, turbulence, chaos, jazz, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, intermittency, transitions, fluctuations, drops, droplets, droploids, elasticity, turbulence, chaos, jazz