Anti-Gravitation · HackerPapers discussions

Anti-Gravitation — mentioned by raattgift

Sun, 06 Nov 2022 02:55:44 GMT

Unfortunately, different quantum spin orientations don't appear to evade the weak equivalence principle. Dropping Bose-Einstein condensates in vacuum drop towers is a popular experiment. An example, "Tests of the Universality of Free Fall with Atoms in Different Spin Orientations", 2016, <http://dx.doi.org/10.1103/PhysRevLett.117.023001> which is the published version of <https://arxiv.org/abs/1503.00433v1>. Likewise, one would not expect a ferromagnet and a ferroic glass to fall differently in a drop tower. Quantum spin is relevant in post-Newtonian (GR-compatible) gravitation, though. Rough…

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Anti-Gravitation — mentioned by raattgift

Sat, 03 Nov 2018 05:42:09 GMT

You asked an interesting question: If (arguendo) anti-matter anti-gravitates, then > Does it not then make sense that in-falling anti-matter would have an evaporating effect Yes, kinda. More precisely, it would depend on how anti-gravitation works exactly, i.e., how anti-matter couples to gravity differently from matter. So even more precisely, "we don't know but can model various remotely plausible ideas with current theory" [a concrete attempt to model below at [1]]. One approach to model anti-matter anti-gravitation is to have a second metric which anti-matter feels but matter doesn't.…

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Anti-Gravitation — mentioned by raattgift

Sat, 03 Mar 2018 19:02:29 GMT

Sabine Hossenfelder has a slightly tongue-in-cheek FAQ on anti-gravitation, and from time to time blogs about it. https://fias.uni-frankfurt.de/~hossi/Physics/anti-gravity.ht... You might find that interesting. The key constraints come from General Relativity; the successes of the Schwarzschild and Kerr(-Newman) metrics for physically plausible arrangements of matter need to be preserved if you try to add in a symmetry. If we use perturbation theory to capture deviations from the metric of a reasonable exact solution to the Einstein Field Equations, the structures can be represented as…

Paper and discussion history. A mention is not an endorsement.