# gst: vortex-pair dance and oscillation

       Fig. 4

This AA study << focuses on fundamental dynamics of vortex-pair fields, specifically known as vortex-pair beams (VPBs) in optics. VPBs have gained increasing attention due to their unique properties, including vortex attraction and repulsion. Here, (AA)  explore the dynamics of pure-phase VPBs (PPVPBs) and observe intriguing helical and intertwined behaviors of vortices, resembling a vortex-pair dance. >>

They << uncover the oscillation property of the intervortex distance for PPVPBs in free space. The observed dancing and oscillation phenomena are intricately tied to the initial intervortex distance and can be explained well in the hydrodynamic picture. Notably, the vortex dancing and oscillation alter the process of vortex-pair annihilation, extending the survival range for opposite vortices. >>

<< This discovery enhances our understanding of vortex interactions and sheds light on the intricate dynamics of both vortex-vortex and vortex-antivortex interactions. >>

Dadong Liu, Lai Chen, Li-Gang Wang. Observation of vortex-pair dance and oscillation. arXiv: 2412.06634v1 [physics.optics]. Dec 9, 2024.

https://arxiv.org/abs/2412.06634

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

Keywords: gst, vortex, dance 

# gst: self-organized chimera states in pulse-coupled oscillator systems.

<< Coupled oscillator systems can lead to states in which synchrony and chaos coexist. These states are called “chimera states.” >>

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AA << study a variation of a pulse-coupled oscillator (PCO) model that has been shown to produce chimera states, demonstrate that it reproduces several of the expected chimera properties, like the formation of multiple heads and the ability to control the natural drift that Kuramoto's chimera states experience in a ring, and explain how chimera states emerge. >>️

<< Three notable aspects of chimeras in our PCO networks (with time-discrete coupling) are the absence of firing events from the tail (which still almost synchronize their phases), the reliable onset of the phenomenon from virtually any initial configuration, and the lack of a superimposed structure (e.g., artificially splitting the population into subgroups) and thus the self-organized nature of the phenomenon. >>️

Arke Vogell, Udo Schilcher, et al. Chimera states in pulse-coupled oscillator systems. Phys. Rev. E 110, 054214. Nov 26, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.054214 

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

Keywords: gst, chimera, self-assembly, chaos, network 

# game: balance exploration and exploitation, making decisions cooperatively without sharing information.

<< Multiagent reinforcement learning (MARL) studies crucial principles that are applicable to a variety of fields, including wireless networking and autonomous driving. (AA) propose a photonic-based decision-making algorithm to address one of the most fundamental problems in MARL, called the competitive multiarmed bandit (CMAB) problem. >>

AA << demonstrate that chaotic oscillations and cluster synchronization of optically coupled lasers, along with (their) proposed decentralized coupling adjustment, efficiently balance exploration and exploitation while facilitating cooperative decision making without explicitly sharing information among agents. >>

AA << study demonstrates how decentralized reinforcement learning can be achieved by exploiting complex physical processes controlled by simple algorithms. >>

Shun Kotoku, Takatomo Mihana, et al. Decentralized multiagent reinforcement learning algorithm using a cluster-synchronized laser network. Phys. Rev. E 110, 064212. Dec 11, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.110.064212

Img: https://x.com/PhysRevE/status/1866889144657465632

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

Keywords: game, cooperation, chaos, exploration, exploitation, ai, artificial intelligence, MARL, CMAB.

# gst: turbulence in viscous binary fluid mixtures induced by interfacial fluctuations.

AA << demonstrate the existence of interface-induced turbulence, an emergent nonequilibrium statistically steady state with spatiotemporal chaos, which is induced by interfacial fluctuations in low-Reynolds-number binary-fluid mixtures. >>️

<< Furthermore (they) demonstrate diffusive behavior at long times, a hallmark of strong mixing in turbulent flows. >>️

Nadia Bihari Padhan, Dario Vincenzi, Rahul Pandit. Interface-induced turbulence in viscous binary fluid mixtures. Phys. Rev. Fluids 9, L122401. Dec 3, 2024. 

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.L122401

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

Keywords: gst, fluctuations, turbulence, transition 

# life: POTUS race, an extreme RAG-time revisited, they moved from Mr. Bernie to Mr. Donald.

<< In the final New York Times/Siena College national poll in late October, nearly two-thirds of voters said the government was “mostly working to benefit itself and the elites,” rather than “the people and the country.” Eighty-two percent of Trump voters said so, twice as many as Kamala Harris voters. >>

<< The idea resonated in particular with men and younger voters, the poll found — groups that Mr. Trump especially courted in this election and that Mr. Sanders did well with in his Democratic primary campaigns in 2016 and 2020. >>

Claire Cain Miller. How Some Voters Moved From Bernie Sanders to Donald Trump. Dec. 9, 2024. 

https://www.nytimes.com/2024/12/09/upshot/voters-trump-bernie-sanders.html

Also: RAG-time revisited. Notes (quasi-stochastic poetry). Feb 18, 2008. 

(RAG: Ralph, Al, George)

https://inkpi.blogspot.com/2008/02/2152-rag-time-revisited.html

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

Keywords: life, RAG-time, Mr. Donald, POTUS

# gst: apropos of puddles, how to design and stabilize a Leidenfrost puddle

<< Leidenfrost puddles exhibit erratic bubble bursts that release vapor trapped beneath the liquid, becoming amorphous and unstable. (AA) report a method to stabilize and design a Leidenfrost puddle. >>

<< When a thin hydrophilic layer with a suitable design is placed over the liquid, the puddle adopts the layer shape due to adhesive forces and becomes stable. (AA) show a variety of puddle designs with the required layer dimensions to avoid vapor accumulation, as well as wetting and buoyancy conditions. >>

<< With the layer, the puddle evaporation rate increases significantly and can be modified by varying the layer dimensions. Finally, an illustrative use of this method in a cooling process is presented. >>️

F. Pacheco-Vázquez, M. Aguilar-González, L. Victoria-García. Designing Leidenfrost Puddles. Phys. Rev. Lett. 133, 234001. Dec 4, 2024. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.234001 

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

Keywords: gst, drops, bubbles, instability, transition

# gst: anomalous oscillation modes of (superfluid) pendant droplets; horizontal translation on a flat surface, bouncing off at the corner and vertical oscillations at the edge.

<< Droplets should exhibit various dynamical phenomena when adhered to a surface; not all of them are realized in classical fluids. Visualization of superfluid  4^He (helium-4) pendant droplets revealed that the droplets were horizontally translated on a flat surface, bouncing off at the corner, known as the Noether mode that reflects the translation symmetry. >>️

<< The droplets exhibited another mode in vertical oscillations with high amplitude that included oscillation of the droplet edge. The oscillation period remained constant even as the droplets grew, exhibiting an anomalously weak size dependence. The high mobility of the droplet edges owing to the superfluidity was a crucial factor for the appearance of these anomalous modes. >>️

Keita Onodera, Ryuma Nagatomo, et al. Anomalous Oscillation Modes of Superfluid Pendant Droplets. Phys. Rev. Lett. 133, 216001. Nov 19, 2024.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.216001

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

Keywords: gst, drop, droplet, droploid, transition