# gst: mitigate | eliminate side lobes from superoscillatory waves (to manipulate nanoparticles)

<< A sharp-edged aperture is a promising solution for eliminating side lobes from superoscillatory waves. >>

<< Optical superoscillation refers to a wave packet that can oscillate locally in a frequency exceeding its highest Fourier component. This intriguing phenomenon enables production of extremely localized waves that can break the optical diffraction barrier. >>

<< The trouble is that strong side lobes accompany the main lobes of superoscillatory waves, which limits the field of view and hinders application. >>️

<< A central microdisc with cylindrical diffraction gives rise to a superoscillatory light spot of a size within the optical diffraction limit. A pair of sharp-edged apertures ensures constructive interference with the high-spatial-frequency waves. That interference effectively eliminates side lobes along a symmetric cut that can be adjusted in the transverse plane by rotating the moonlike apertures. >>

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<< the cylindrical diffraction of the central microdisc produces superoscillatory waves with Bessel-like forms. These forms enable the delicate structures of the superoscillatory waves propagating in free space to travel much farther than the evanescent light waves. (..) this intriguing propagation effect of superoscillation holds promise for potential application in nanoparticle manipulation, as well as superresolution imaging. >>️

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Optical superoscillation without side waves. SPIE-International Society for Optics and Photonics. Jun 24, 2021.

https://www.sciencedaily.com/releases/2021/06/210624170837.htm

Yanwen Hu, Shiwang Wang, et al. Optical superoscillatory waves without side lobes along a symmetric cut. Advanced Photonics, 3(4), 045002 doi: 10.1117/ 1.AP.3.4.045002. Jun 23, 2021. 

https://www.spiedigitallibrary.org/journals/advanced-photonics/volume-3/issue-4/045002/Optical-superoscillatory-waves-without-side-lobes-along-a-symmetric-cut/10.1117/1.AP.3.4.045002.full

# gst: apropos of turbulence, self-similarity of turbulent flows with internal and external intermittency

<< Scientists have long used supercomputers to better understand how turbulent flows behave under a variety of conditions. Researchers have now include the complex but essential concept of 'intermittency' in turbulent flows. >>️

<< Despite its seemingly random, chaotic characteristics, researchers have identified some important properties that are universal, or at least very common, for turbulence under specific conditions. (..) Much of that important turbulent motion may stem from what happens in a thin area near the edge of the flame, where its chaotic motions collide with the smoother-flowing fluids around it. This area, the turbulent-non-turbulent interface (TNTI), has big implications for understanding turbulent mixing. >>️

<< Scientists distinguish between internal intermittency, which occurs at the smallest scales and is a characteristic feature of any fully developed turbulent flow, and external intermittency, which manifests itself at the edge of the flame and depends on the structure of the TNTI. >>️

<< For Bode and Gauding (Mathis Bode, Michael Gauding), understanding the small-scale turbulence happening at the thin boundary of the flame is the point. >>

<< Our simulations are highly resolved and are interested in these thin layers, (..) For production runs, the simulation resolution is significantly higher compared to similar DNS (direct numerical simulations ) to accurately resolve the strong bursts that are connected to intermittency. >> Mathis Bode. 

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Simulations of turbulence's smallest structures. Gauss Centre for Supercomputing. Jul 8, 2021. 

https://www.sciencedaily.com/releases/2021/07/210708103609.htm

<< In turbulent jet flows, the phenomenon of external intermittency originates from a sharp layer, known as the turbulent/ non-turbulent interface, that separates the turbulent core from the surrounding irrotational fluid. First, it is shown that low-order and higher-order structure functions in both the core and the shear layer of the jet satisfy complete self-preservation, which means that structure functions are invariant with time and collapse over the entire range of scales, regardless of the set of length and velocity scales used for normalization. Next, the impact of external intermittency on small-scale turbulence is studied along the cross-wise direction by the self-similarity of structure functions. It is shown that structure functions exhibit from the centre toward the edge of the flow a growing departure from self-similarity and the prediction of classical scaling theories. By analysing statistics conditioned on the turbulent portion of the jet, it is demonstrated that this departure is primarily due to external intermittency and the associated similarity-breaking effect. >>️

Michael Gauding, Mathis Bode, et al. Self-similarity of turbulent jet flows with internal and external intermittency. Journal of Fluid Mechanics.  919 , 25, A41. doi: 10.1017/ jfm.2021.399. Jun 1,  2021.

https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/abs/selfsimilarity-of-turbulent-jet-flows-with-internal-and-external-intermittency/170B9415870F47A94D041FEE7E904840

Michael Gauding, Mathis Bode, et al. On the combined effect of internal and external intermittency in turbulent non-premixed jet flames. Proceedings of the Combustion Institute. 38, (2): 2767-2774. doi: 10.1016/ j.proci.2020.08.022. Dec 9, 2020.

https://www.sciencedirect.com/science/article/abs/pii/S1540748920306064

keyword 'Intermittency' in ScienceDirect

https://www.sciencedirect.com/topics/engineering/intermittency

Also

1939 - stocastici accessi (di traslitteranti ludi). Notes. Jan 11, 2006. 

(quasi-stochastic poetry )

https://inkpi.blogspot.com/2006/01/1939-stocastici-accessi-di.html

2064 - on responses to deviant stimuli.

Notes. Sep 26, 2006. (quasi-stochastic poetry )

https://inkpi.blogspot.com/2006/09/2064-on-responses-to-deviant-stimuli.html

# gst: apropos of 'disordered interactions', localization and dissociation of bound states and mapping to chaotic billiards concerning two particles on a chain

AA << consider two particles hopping on a chain with a contact interaction between them. At strong interaction, there is a molecular bound state separated by a direct gap from a continuous band of atomic states. Introducing weak disorder in the interaction, the molecular state becomes Anderson localized (exponential localization of all energy eigenstates,). At stronger disorder, part of the molecular band delocalizes and dissociates due to its hybridization to the atomic band. (AA) characterize these different regimes by computing the density of states, the inverse participation ratio, the level-spacing statistics and the survival probability of an initially localized state.  >>️

<< The atomic band is best described as that of a rough billiard for a single particle on a square lattice that shows signatures of quantum chaos. In addition to typical ``chaotic states'', (AA) find states that are localized along only one direction. These ``separatrix states'' are more localized than chaotic states, and similar in this respect to scarred states, but their existence is due to the separatrix iso-energy line in the interaction-free dispersion relation, rather than to unstable periodic orbits. >> 

Hugo Perrin, Janos K. Asboth, et al.  Two particles on a chain with disordered interaction: Localization and dissociation of bound states and mapping to chaotic billiards. arXiv: 2106.09603v1. Jun 17, 2021. 

https://arxiv.org/abs/2106.09603

# gst: apropos of (multitudes) of transitional droplets, when a liquid film collapses in a foam ...

<< Foams have unique properties that distinguish them from ordinary liquids and gases, and are ubiquitously observed in nature, both in biological systems and industrial products. >>

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<< Once a crack appears near the border and a collapse front is formed, (AA) find that the curvature of the front reverses as it migrates, followed by the emergence and emission of droplets. (they) elucidate the origins of this behavior and discuss the stability of foams, establishing how the characteristic time scales of the process relate to each other. >>️

Naoya Yanagisawa, Marie Tani, Rei Kurita. Dynamics and mechanism of liquid film collapse in a foam. Soft Matter. 17, 1738-1745. Feb 17, 2021.

https://pubs.rsc.org/en/content/articlelanding/2021/SM/D0SM02153A#

Also

keyword 'foam' in FonT

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

keyword 'collapse' in FonT

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

keyword 'schiuma' in Notes

(quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=schiuma

# gst: emergence of the traveling chimera, imperfect-traveling, traveling multi-clusters, and alternating traveling chimera in a two-dimensional network

<< Neuronal synchronization being a phenomenon linked to several brain pathologies such as epilepsy, Parkinson diseases, Alzheimer, autism and schizophrenia, does not always appear in a singular way in neuronal networks. Its presence (state of coherence) accompanied simultaneously by an asynchronous state (state of incoherence) has been demonstrated (..) in the networks of identical oscillators not locally coupled. This phenomenon was later termed the chimera state. (..) Chimera states are analogously to the cerebral behaviors of certain aquatic mammals and migratory birds, which during their movements half part of their brains asleep while the rest are awake.  >>️

AA << study the emergence of the traveling chimera state in a two-dimensional network of (..) burst neurons with the mutual presence of local and non-local couplings. (AA) show that in the unique presence of the non-local chemical coupling modeled by a nonlinear function, the traveling chimera phenomenon occurs with a displacement in both directions of the plane of the grid. The introduction of local electrical coupling shows that the mutual influence of the two types of coupling can, for certain values, generate traveling chimera, imperfect-traveling, traveling multi-clusters, and alternating traveling chimera, ie the presence in the network under study, of patterns of coherent elements interspersed by other incoherent elements in movement and alternately changing their position over time. The confirmation of the states of coherence is done by introducing the parameter of instantaneous local order parameter in two dimensions. >>️

Gael R. Simo, Patrick Louodop, et al. Traveling chimera patterns in two-dimensional neuronal network. arXiv:2106.08400v1. Jun 9, 2021.

https://arxiv.org/abs/2106.08400

# life: Modern Jazz Quartet (MJQ) revisited (precarious attempt to revisit)

Even the impulsive epiphany of Mr. Grillo @beppe_grillo and Mr. Conte @GiuseppeConteIT reminded me of the intriguing story of MJQ ...

2124 - attrattore cooperativo bipolare (nell' elastici spigoli). Mar 05, 2007. (quasi-stochastic poetry)

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

The point is that MJQ were talented professionals in (conversational, cooperative, hacking-craking) chaotic phrasing ...

instead this just feels like unstructured chaos

Jason Horowitz. How Giuseppe Conte of Italy Went From Irrelevant to Irreplaceable. NYT. Aug. 29, 2019.

https://www.nytimes.com/2019/08/29/world/europe/italy-conte-government-salvini.html

Conte-Grillo, what are the points of conflict that split the M5S. June 27, 2021. 

https://www.italy24news.com/local/99913.html

PostNote

Apropos of the "ulteriore elemento di impredicibilità" (further element of unpredictability)   https://inkpi.blogspot.com/2007/03/2124-attrattore-cooperativo-bipolare.html   the inkling about the image of an acyclic bipolar avatar generated and controlled by an artificial intelligence - characterized by sufficient degrees of freedom and self-maintenance - could, hypothetically, create and modulate (unexpected) novelties, not necessarily at least in a first approximation, with  harmful-self-damaging outcomes. 

# gst: weird Nature; randomly arranged nanowire networks seem to behave, at the edge of chaos, like cortical neuronal cultures

<< an artificial network of nanowires can be tuned to respond in a brain-like way when electrically stimulated. >>️

<< If the signal stimulating the network was too low, then the pathways were too predictable and orderly and did not produce complex enough outputs to be useful. If the electrical signal overwhelmed the network, the output was completely chaotic and useless for problem solving. The optimal signal for producing a useful output was at the edge of this chaotic state. >>️

<< Some theories in neuroscience suggest the human mind could operate at this edge of chaos, or what is called the critical state, (..) Some neuroscientists think it is in this state where we achieve maximal brain performance. (..) What's so exciting about this result is that it suggests that these types of nanowire networks can be tuned into regimes with diverse, brain-like collective dynamics, which can be leveraged to optimize information processing. >> Zdenka Kuncic.️

<< In the nanowire network the junctions between the wires allow the system to incorporate memory and operations into a single system. This is unlike standard computers, which separate memory (RAM) and operations (CPUs). >>

<< These junctions act like computer transistors but with the additional property of remembering that signals have traveled that pathway before. As such, they are called 'memristors', >> Joel Hochstetter.

️

'Edge of chaos' opens pathway to artificial intelligence discoveries. University of Sydney. Jun 29, 2021.

https://phys.org/news/2021-06-edge-chaos-pathway-artificial-intelligence.html

Joel Hochstetter, Ruomin Zhu, et al. Avalanches and edge-of-chaos learning in neuromorphic nanowire networks. Nat Commun 12, 4008. doi: 10.1038/ s41467-021-24260-z. Jun 29, 2021.

https://www.nature.com/articles/s41467-021-24260-z