Month: September 2022

BLACK HOLE MERGERS. “This first gravitational wave event, GW150914, appears to have been caused by the merger to two fairly massive (∼30 M⊙) black holes. Subsequent detections of a BBH mergers (GW151226 and GW170104) and a candidate BBH event (LVT151012) have allowed more robust estimates of the local BBH merger rate density and have confirmed the existence of black holes involved in these mergers with masses that range from 7.5 to 36  M⊙.” (BBH = binary black hole). https://lnkd.in/d8Jh7TB View in LinkedIn

SCALAR SUPERSYMMETRY. “Apart from curing the Higgs mass finetuning problem, supersymmetry leads to gauge coupling unification, provides candidates for Dark Matter, and sets the stage for gravity unification via superstrings.” All clear? https://lnkd.in/dfNrUJy View in LinkedIn

Blushing with modesty, this spring tulip is rediculous. A sport of nature. View in LinkedIn

FRAGMENT FROM NATURE for this and next weekend focuses in a remarkable essay authored by two MSc students and their advisors who made observations on the jamming of material like sand in a funnel, and derived conclusions about relativity and black holes from it. Johannes Kepler’s famous 1610 essay in the six sided snowflake similarly extrapolated from a snowflake to material packing. It is in the honored tradition of serious people making observations on things like peacock feathers, beetle casings and butterfly wing scales and deriving conclusions about optics from them. https://lnkd.in/duxTaRF View in LinkedIn

IT IS ASSUMED by most of us that the macro is a fractal reflection of sorts of the micro. But this ignores the phenomenon of emergence that occurs when simple elements aggregate to form complexity with unexpected properties that are not the sum of its parts. That said, this essay on coarse material jamming is a diamond in the rough, and the two professors were lucky to have such talented students. https://lnkd.in/dusKMKM View in LinkedIn

JAMMING. “Granular matter, and indeed many other athermal amorphous materials, exhibit an intriguing property known as jamming. The standard characterization of this phenomenon is in terms of strong stress heterogeneities occurring in the material, with and without an externally applied stress.” https://lnkd.in/dusKMKM View in LinkedIn

GRAIN ALIGNMENT. “Within this paradigm, spatial density fluctuations observed in a granular material like sand, are attributed to force chains - force-ordered alignments of grains which inhibit motion of test-grains along the alignment direction (friction).” https://lnkd.in/dusKMKM View in LinkedIn

DUAL STATES. “Thus, in each such alignment direction, these materials behave like a solid, while, in other directions, the material may indeed ‘flow’, akin to a fluid.” (Very quantum description in macroscopic material!) https://lnkd.in/dusKMKM View in LinkedIn

THE PROBLEM. “This dichotomic behaviour is at the heart of difficulties in the extensive ongoing and past assays in theoretical analyses of the laws that govern such materials.” https://lnkd.in/dusKMKM View in LinkedIn

CONFLICTING STATES. “The laws appear to have firm underpinnings in out-of-equilibrium, nonlinear physical interactions, even though jamming per se appears to be a steady state feature.” https://lnkd.in/dusKMKM View in LinkedIn