# 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

# gst: apropos of clogging and jamming, they are not really jammed, they move steadily, if slowly, downwards

<< The first study of the way logs become pinned in rivers reveals that those seemingly trapped in a logjam move steadily, if slowly, downriver. >>

<< One of the lesser-known consequences of forest fires is logjams—river channels clogged with wood. The mechanism is straightforward. Forest fires create vast areas of dead wood. During the winter, heavy snow leads to avalanches that push thousands of the burned logs to the bottom of river valleys, where they enter the water. When the logs stretch across the river, from bank to bank, the river can no longer flow. It is this formation that has long captured the public imagination: the word "logjam" has come to mean a situation in which movement, physical or otherwise, is impossible. >>

Logjams aren’t really jammed at all, say geoscientists. Tech Rev - Emerging Technology from the arXiv. Nov 19, 2019

https://www.technologyreview.com/s/614724/logjams-arent-really-jammed-at-all-say-geoscientists/

Nakul S. Deshpande, Benjamin T. Crosby. Logjams are not jammed: measurements of log motions in Big Creek, Idaho. arXiv:1911.01518v1 [physics.geo-ph]. Nov 4, 2019.

https://arxiv.org/abs/1911.01518

# gst: the dance of complex knots (in DNA), from mobile to jammed states

AA << show for the first time experimentally that knots can go from a mobile to a jammed state by varying an applied strain rate, and that this jamming is reversible >>

Alexander R. Klotz, Beatrice W. Soh, and Patrick S. Doyle. Motion of Knots in DNA Stretched by Elongational Fields.  Phys. Rev. Lett. 120, 188003. May 3, 2018.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.188003

Anne Trafton. Chemical engineers discover how to control knots that form in DNA molecules. Massachusetts Institute of Technology. May 3, 2018.

https://m.phys.org/news/2018-05-chemical-dna-molecules.html

# gst: like grains of sand in a sandcastle

<< Cells comprising a tissue can pack into disorderly geometries much as do grains of sand in a sandcastle. In doing so they can freeze into a fixed shape—as in a sandcastle—or flow like sand poured from a beach bucket >>

<< This finding makes a deep connection between the physics of inert granular matter such as sand and the geometry of multicellular living systems >> Lior Atia.

Harvard T.H. Chan School of Public Health. Sandcastles and surprising origins of basic cellular functions. Apr 2, 2018

https://m.phys.org/news/2018-04-sandcastles-basic-cellular-functions.html

Lior Atia, Dapeng Bi, et al. Geometric constraints during epithelial jamming. Nature Physics. doi: 10.1038/s41567-018-0089-9. Apr 2, 2018.

https://www.nature.com/articles/s41567-018-0089-9