# gst: exotic geometries, a Janus trefoil knot, which rotates as it swims forwards.

AA << present an asymptotic theory for solving the dynamics of slender autophoretic loops and knots. >>️

They << elucidate the behavior of many exotic active particle geometries, such as a bumpy uniformly active torus that spins and a Janus trefoil knot, which rotates as it swims forwards. >>️

Panayiota Katsamba, Matthew D. Butler, et al. Slender phoretic loops and knots. Phys. Rev. Fluids 9, 054201. May 10, 2024. 

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.054201

Also: keywords janus, knots, particle, in FonT

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

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

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

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

Keywords: janus, loops & knots, particles

# game: apropos of Parrondo's game, how a flexible parasite can outsmart its hosts for evolutionary dominance.

<< Antagonistic coevolution between hosts and parasites substantially impacts community structure, with parasites displaying fluctuating selection or arms race dynamics during coevolution. The traditional matching alleles (MA) and gene-for-gene (GFG) models have been used to describe the dynamics and interaction of host-parasite coevolution, with these models assuming that parasites adopt a single strategy when competing with other parasites. >>

AA << present a nonlinear dynamic population model that challenges this assumption, showing how a parasite that is disadvantaged under either the MA or the GFG model can win the competition by switching between the two losing strategies based on an external environmental cue, internal processes, or stochastic decision-making. >>

<< This counterintuitive outcome is analogous to Parrondo's paradox, a game-theoretic concept that shows how alternating between two losing strategies can result in a winning outcome. >>

Tao Wen, Eugene V. Koonin, Kang Hao Cheong. How flexible parasites can outsmart their hosts for evolutionary dominance. Phys. Rev. Research 6, 023104. Apr 30, 2024.

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.6.023104 

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

Keywords: game, Parrondo, evolution

FonT: from my point of view, if well modulated, the two paired strategies "Stochastic Tit-For-Tat" and "Parrondo" are deadly, regardless of the aims of the objectives (cooperative purposes, parasitism, etc)

# gst: relativistic chaotic scattering, scaling laws for trapped trajectories.

AA << study different types of phase space structures which appear in the context of relativistic chaotic scattering. By using the relativistic version of the Hénon-Heiles Hamiltonian, (They) numerically study the topology of different kind of exit basins and compare it with the case of low velocities in which the Newtonian version of the system is valid. >>

<< In all cases, fractal structures are present, and the escaping dynamics is characterized. In every case a scaling law is numerically obtained in which the percentage of the trapped trajectories as a function of the relativistic parameter β and the energy is obtained. >>

Their << work could be useful in the context of charged particles which eventually can be trapped in the magnetosphere, where the analysis of these structures can be relevant. >>️

Fernando Blesa, Juan D. Bernal, et al. Relativistic chaotic scattering: Unveiling scaling laws for trapped trajectories. Phys. Rev. E 109, 044204. Apr 5, 2024.

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.109.044204

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

Keywords: gst, chaos, chaotic, escape, escape trajectories

# gst: apropos of avoidance, packing of stiff rods on ellipsoids; the effects of self-avoidance

AA << study the effects of geometry and self-avoidance on the ordering of slender filaments inside nonisotropic containers, considering cortical microtubules in plant cells, and packing of genetic material inside viral capsids as concrete examples. >>

<< Within a mean-field approximation, (AA) show analytically how the shape of the container, together with self-avoidance, affects the ordering of the stiff rods. (They)  find that the strength of the self-avoiding interaction plays a significant role in the preferred packing orientation, leading to a first-order transition for oblate cells, where the preferred orientation changes from azimuthal, along the equator, to a polar one, when self-avoidance is strong enough. >>

<< While for prolate spheroids the ground state is always a polar-like order, strong self-avoidance results with a deep metastable state along the equator. >>

<< the critical behavior of this system is in fact related to the butterfly catastrophe model. >>

Doron Grossman, Eytan Katzav. Effects of self-avoidance on the packing of stiff rods on ellipsoids. Phys. Rev. E 109, 054111. May 9, 2024. 

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.109.054111

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

Keywords: gst, ellipsoids, spheroids,  oblate- prolate spheroids, avoidance, self-avoidance

# gst: quantum jamming on the macroscopic scale

 << In the presence of kinetic constraints, quasiparticles describing the behavior of an ordered arrangement of quantum spins can get “stuck” as their density increases. Because of its similarity to the formation of amorphous solids, this situation can be interpreted as the quantum analog of jamming. Jammed states are intrinsically unstable and small perturbations produce unusual nonequilibrium dynamics. >> 

 AA << show that quantum jamming is a mechanism to make microscopic phenomena visible at a macroscopic scale: A single impurity produces a permanent change in the state, and a few impurities leave an imprint of their scattering properties and bound states. >> 

Maurizio Fagotti. Quantum Jamming Brings Quantum Mechanics to Macroscopic Scales. Phys. Rev. X 14, 021015. Apr 23, 2024.

https://journals.aps.org/prx/abstract/10.1103/PhysRevX.14.021015

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

Keywords: gst, particle, jamming

# music: masters of noise, Frank Zappa plays bicycles

Frank Zappa teaches Steve Allen to play The Bicycle (aired March 3, 1963).

https://youtu.be/QF0PYQ8IOL4

<< This televisual gem inspired me follow along which got me into endless trouble at family picnics and barbecues for playing my own symphonic masterpieces which, for some strange reason, nobody else seemed to enjoy. I extended Frank's genius to my exploration of the vacuum cleaner, ping pong balls and paddles, (..)  The next time you're out in a forest I challenge you to explore the musical nature of nature for yourself. Trees make great drums and often ring with higher tones - not to mention the musical benefits of rocks and stones. >>️️

That Hairy Canadian. Jun 21, 2014. 

https://m.youtube.com/@ThatHairyCanadian

Also: music, jazz, noise, error, in https://www.inkgmr.net/kwrds.html 

Keywords: music, jazz, noise, error

# gst: bubble phases sliding over periodically modulated substrates

AA << analyze a bubble-forming system composed of particles with competing long-range repulsive and short-range attractive interactions driven over a quasi-one-dimensional periodic substrate. >>️

They << find various pinned and sliding phases as a function of substrate strength and drive amplitude. When the substrate is weak, a pinned bubble phase appears that depins elastically into a sliding bubble lattice. For stronger substrates, (AA) find anisotropic bubbles, disordered bubbles, and stripe phases. Plastic depinning occurs via the hopping of individual particles from one bubble to the next in a pinned bubble lattice, and as the drive increases, there is a transition to a state where all of the bubbles are moving but are continuously shedding and absorbing individual particles. This is followed at high drives by a moving bubble lattice in which the particles can no longer escape their individual bubbles. >>️

<< When the bubbles shrink due to an increase in the attractive interaction term, they fit better inside the pinning troughs and become more strongly pinned, leading to a reentrant pinning phase. For weaker attractive terms, the size of the bubbles becomes greater than the width of the pinning troughs and the depinning becomes elastic with a reduced depinning threshold. >>

️

C. Reichhardt, C.J.O. Reichhardt. Sliding dynamics for bubble phases on periodic modulated substrates. Phys. Rev. Research 6, 023116. May 2, 2024.

https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.6.023116

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

Keywords: gst, bubble, pinned bubble, elastic, transition