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THE END OF PHYSICS. (1894) Albert Michelson + Edward Morley, whose famous experiment refuted the existence of the luminiferous ether, said “that the great principles had already been discovered, and that physics would henceforth be limited to finding truths in the sixth decimal place.” (Just before Einstein unveiled relativity!). https://lnkd.in/dq9jWpt View in LinkedIn

EXHAUSTING KNOWN GEOMETRY. “The classical growth of the black hole interior shown in figure 2 cannot go on forever: the black hole eventually runs out of linearly independent classical geometries, and a transition must occur from the complexity ramp to a complexity plateau.” https://lnkd.in/d3Fw6gf View in LinkedIn

STUCK IN WONDERLAND. “Classical GR governs the interior of an eternal AdS black hole for a tiny fraction of the time. The rare “classical” episodes last for a time ∼ eS and in between them the black hole exists in a vast doubly exponential sea of time, stuck in a state of complexity equilibrium. Very little is known about the geometry of the interior, if indeed it has a geometry, during these periods of equilibrium.” (GR = general relativity). https://lnkd.in/d3Fw6gf View in LinkedIn

THE PHYSICIST’S ANSWER. “The interesting fact is not that there are three different answers to three different questions for t > texp. What is remarkable is that for t < texp all three give the same answer; namely, there is a unique classical wormhole geometry whose length, volume, and action grow linearly with time in agreement with the classical Einstein equations. At exponential time the agreement breaks down and the three questions have different answers.” https://lnkd.in/d3Fw6gf 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

THE PHILOSOPHER’S KNOT. “The three possibilities are all correct but they answer different questions.” https://lnkd.in/d3Fw6gf 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

COMPLEX GEODESICS. “Geodesics in Complexity Geometry. If the geometry is defined by the usual inner product metric then the curve will be a geodesic for any H. Geodesics generated in this way are not homogeneous along their length.” https://lnkd.in/d3Fw6gf 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