Tootfinder

from my link log —
Special Relativity Boot Camp: A geometry-first introduction to Special Relativity for advanced undergraduate and beginning graduate students.
https://www.acsu.buffalo.edu/~whkinney/SpecialRelativityBootCamp/
saved 2026-08-01

#blackholes

A Star Orbiting Our Galaxy's Supermassive Black Hole Tests the Limits of Relativity - Universe Today https://www.universetoday.com/articles/a-star-orbiting-our-galaxys-supermassive-black-hole-tests-the-limits-of-relativi…

my #geometryOnDrugs postings continue after a bit of a hiatus.
Today's entry: The first installment of my intro to hyperbolic geometry. This is basically going to parallel (pun intended) what I did with spherical geometry some years back, except this will inevitably be more weird (surprise).

Information--Theoretic Black Hole Entropy II: Infrared Gravity and Charged/Rotating Extensions
Alex Kehagias
https://arxiv.org/abs/2608.05801 https://arxiv.org/pdf/2608.05801 https://arxiv.org/html/2608.05801
arXiv:2608.05801v1 Announce Type: new
Abstract: We investigate gravitational and Kerr-Newman extensions of an information-theoretic black-hole entropy that satisfies the Nernst formulation of the third law of thermodynamics. The entropy is identified with the Kullback-Leibler divergence between a mass-dependent Bernoulli ensemble and an unbiased reference ensemble, and therefore measures relative information rather than the logarithm of the number of black-hole microstates. We show perturbatively that its temperature and entropy can be reproduced by an infrared deformation of General Relativity. To linear order in the deformation couplings, the surface-gravity temperature and the Wald entropy agree with the information-theoretic results. In an explicit realization, the matching generates a positive effective cosmological term whose smallness is related to the large microscopic parameter $N$. We also propose an extension to Kerr-Newman black holes based on the irreducible mass. This construction preserves the connection with the horizon area and the semiclassical limit, while distinguishing geometrical extremality from the universal statistical-freezing endpoint, which is independent of angular momentum and charge.
toXiv_bot_toot

Breakthrough Quantum Test Resolves a Major Cosmic Mystery https://www.404media.co/breakthrough-quantum-test-resolves-a-major-cosmic-mystery/

Isomorphic Emergence of Lorentz and Gauge Symmetries--A Constructive Interpretation Based on Continuum Mechanics
Ke-Xia Jiang
https://arxiv.org/abs/2608.06244 https://arxiv.org/pdf/2608.06244 https://arxiv.org/html/2608.06244
arXiv:2608.06244v1 Announce Type: new
Abstract: Lorentz symmetry and gauge symmetry constitute the mathematical cornerstones of modern physics, yet their ultimate physical origins remain elusive. From the standpoint of a constructive interpretation, this paper demonstrates that both symmetry structures can emerge isomorphically from a unified classical source: dynamical constraints on wave-packet excitations in a continuous elastic substrate medium (SM). Neither symmetry is posited as fundamental, nor does their emergence rely on quantization. Three core results are established. First, taking the transverse wave speed of a homogeneous, isotropic SM as the benchmark under a conventionalist synchronization scheme, Minkowski-type spacetime arises isomorphically, with Lorentz transformations as effective coordinate transformations between inertial frames. This reinterprets the Michelson--Morley null result: observers are composite wave-packet excitations, and medium-induced kinematic corrections are encoded in their measurement frameworks. Second, for wave packets endowed with $SU(N)$ intrinsic symmetry, the requirement of identity invariance drives the SM to spontaneously generate gauge fields. This requires invariant equivalence classes of intrinsic states under propagation, yielding gauge structures isomorphic to Yang-Mills theory. The gauge group $SU(N)$ is uniquely determined by the number of stable normal modes supported by the medium. Third, through the same conventionalist measurement protocols, inhomogeneous distributions of the SM emerge isomorphically as curved spacetime geometry, governed by Einstein-type field equations from variational extremization of the medium's deformation free energy. This paper advances a unified interpretive account of the physical origin underlying the mathematical structures of both Relativity and the Standard Model.
toXiv_bot_toot