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martedì 20 settembre 2022
# gst: multiple external fields can modulate confined active particles
venerdì 23 febbraio 2024
# gst: soft and stiff modes in colloidal particle networks
mercoledì 30 marzo 2022
# gst: solitary wave billiards
giovedì 15 aprile 2021
# phys: apropos of transitions, even a tiny wobble may reshape theoretical views of the universe
lunedì 24 aprile 2023
# gst: emergent organization and polarization due to active fluctuations.
lunedì 8 aprile 2024
# gst: apropos of evaporation, puncturing of active drops
venerdì 19 novembre 2021
# gst: apropos of oscillations, viscous streaming around an immersed microfeature (e.g. a bubble)
venerdì 18 agosto 2023
# gst: emergence of self-organizing zigzag patterns among (magnetic) particles suspended in a liquid
mercoledì 12 luglio 2017
# s-phys: more about retrocausality
<< In a new paper (..) [AA] have lent new theoretical support for the argument that, if certain reasonable-sounding assumptions are made, then quantum theory must be retrocausal >>
<< retrocausality means that, when an experimenter chooses the measurement setting with which to measure a particle, that decision can influence the properties of that particle (or another particle) in the past, even before the experimenter made their choice. In other words, a decision made in the present can influence something in the past >>
<< "Speculatively, if there is retrocausality in the universe, then it might be the case that there are certain eras, perhaps near the big bang, in which there is not a definite arrow of causality. You might imagine that a signature of such an era might show up in cosmological data, such as the cosmic microwave background. However, this is very speculative, and I have no idea what signatures we might expect yet." >> Matthew S. Leifer.
<< The physicists don't have any experiments lined up to test retrocausality—but as the idea is more an interpretation of observations rather than making new observations, what's needed most may not be a test but more theoretical support >>
Lisa Zyga. Pysicists provide support for retrocausal quantum theory, in which the future influences the past. July 5, 2017.
https://m.phys.org/news/2017-07-physicists-retrocausal-quantum-theory-future.html
Matthew S. Leifer, Matthew F. Pusey. Is a time symmetric interpretation of quantum theory possible without retrocausality? Proc. Royal Soc. A. June 2017 Volume 473, issue 2202 doi: 10.1098/rspa.2016.0607 Publ. Jun. 21, 2017.
http://rspa.royalsocietypublishing.org/content/473/2202/20160607
venerdì 6 settembre 2019
# gst: apropos of swirling granular media, a geometric frustration; will these entities turn left or right?
<< Granular material in a swirled container exhibits a curious transition as the number of particles is increased: At low densities, the particle cluster rotates in the same direction as the swirling motion of the container, while at high densities it rotates in the opposite direction. >>
AA << show that the transition to counterrotation is friction dependent. At high particle densities, frictional effects result in geometric frustration, which prevents particles from cooperatively rolling and spinning. Consequently, the particle cluster rolls like a rigid body with no-slip conditions on the container wall, which necessarily counterrotates around its own axis. Numerical simulations verify that both wall-disk friction and disk-disk friction are critical for inducing counterrotation. >>
Lisa M. Lee, John Paul Ryan, et al. Geometric frustration induces the transition between rotation and counterrotation in swirled granular media. Phys. Rev. E 100, 012903. July 8, 2019. https://journals.aps.org/pre/abstract/10.1103/PhysRevE.100.012903
Leah Burrows. Solving the pancake problem. Harvard University. Aug 30, 2019. https://m.phys.org/news/2019-08-pancake-problem.html
sabato 29 ottobre 2022
# gst: two steady collective states in swarmalators with delayed interactions
lunedì 11 dicembre 2023
# gst: scanning inside a granular raft
lunedì 20 novembre 2023
# gst: collective patterns generated by capillary surfers.
martedì 16 aprile 2024
# gst: apropos of collective behaviors, a visual model to reproduces swarming, schooling, and milling.
martedì 21 giugno 2022
# gst: even tight-binding billiards could exhibit chaotic behaviors
giovedì 22 giugno 2023
# gst: the effects of order- disorder on a system of swarmalators that move on a one-dimensional ring.
sabato 26 settembre 2020
# gst: how small particles could reshape an asteroid
mercoledì 24 maggio 2023
# gst: intricate transitions in elastoactive structures.
martedì 20 dicembre 2022
# gst: slow dynamics of a interacting mobile impurity (in a bath of localized particles)
mercoledì 25 aprile 2018
# gst: the vacuum may not be empty, it may be full of bubbles.
<< In modern quantum mechanical theories, the vacuum is not empty. It is full of bubbles of so-called virtual particles, appearing and disappearing very quickly. Interactions between these virtual particles and a real particle, like the muon, can change how the real particle interacts with the magnetic field, affecting its g-factor >>
Savannah Mitchem, Argonne National Laboratory. Muons spin tales of undiscovered particles. Apr 19, 2018.
https://www.anl.gov/articles/muons-spin-tales-undiscovered-particles
https://m.phys.org/news/2018-04-muons-tales-undiscovered-particles.html