Comment by westurner | Hacker News Reader

Comment by westurner | Hacker News Reader

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The space changes, so GR and the speed of light are preserved.

"Slow and fast light in plasma using optical wave mixing" (2021) https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.12... .. https://scholar.google.com/scholar?cluster=94797501996846831... :

> We show the first experimental demonstration of slow and fast light in a plasma, measuring group velocities between 0.12⁢c and −0.34⁢c .

Also, photons can be FTL (relative to an outside observer) in dielectrics;

> LightSlinger antennae are FTL within the dielectric, but the EMR is not FTL; from https://news.ycombinator.com/item?id=37342016

Also, do these findings apply to this post-Fourier model of thermal spreading limits at material interfaces given phase ? From https://news.ycombinator.com/item?id=45921309 :

> ScholarlyArticle: "Time-domain theory of transient heat conduction in the local limit" (2025) https://journals.aps.org/prb/abstract/10.1103/p8wg-p1j3

> NewsArticle: "From engines to nanochips: Physicists redefine how heat really moves" (2025-10) https://phys.org/news/2025-10-nanochips-physicists-redefine....

But specifically on velocity in superfluids or superfluids aka BEC Bose-Einstein Condensates,

This model predicts the multi body gravitational motions of the planets including the perihelion of Mercury and also vortices in superfluids:

"Physical vacuum as a dilatant fluid yields exact solutions to Pioneer anomaly and Mercury’s perihelion precession" (2019) https://cdnsciencepub.com/doi/10.1139/cjp-2018-0744 .. https://news.ycombinator.com/item?id=45220585

This model derives gravity from the Standard Model of particle physics:

"Perihelion precession of planetary orbits solved from quantum field theory" (2025) https://arxiv.org/abs/2506.14447 .. https://news.ycombinator.com/item?id=45220460

And this model describes all in terms of consistency maximization

> "The Self-Consistent Coherence-Maximizing Universe: Complete Derivation of the Standard Model and General Relativity from Mathematical Self-Consistency" (2025) https://www.academia.edu/144466150/The_Self_Consistent_Coher... :

> Abstract: We derive the complete structure of fundamental physics from a single principle: Quantum coherence maximization under self-consistency constraints. [...]

And this model describes all terms in terms of Consistency Functional K; https://news.ycombinator.com/item?id=45909513 :

"The Consistency Functional K: Variational Unification of Quantum Mechanics, Thermodynamics, and General Relativity" (2025) https://doi.org/10.5281/zenodo.17405041

  \delta\mathcal{K}(\rho, g) = 0

And Wolfram has a unified theory, too

What are the limits to model unification?

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