https://arxiv.org/pdf/2309.12083.pdf "Varying fundamental constants meet Hubble" <https://arxiv.org/pdf/2309.12083.pdf> Abstract Fundamental physical constants need not be constant, neither spatially nor temporally. – This seeming simple statement has profound implications for a wide range of physical processes and interactions, and can be probed through a number of observations. In this chapter, we highlight how CMB measurements can constrain variations of the fine-structure constant and the electron rest mass during the cosmological recombination era. The sensitivity of the CMB anisotropies to these constants arises because they directly affect the cosmic ionization history and Thomson scattering rate, with a number of subtle atomic physics effects coming together. *Recent studies have revealed that variations of the electron rest mass can indeed alleviate the Hubble tension, as we explain here*. Future opportunities through measurements of the cosmological recombination radiation are briefly mentioned, highlighting how these could provide an exciting avenue towards uncovering the physical origin of the Hubble tension experimentally.
On Sun, Apr 7, 2024 at 7:53 PM James Bowery <jabow...@gmail.com> wrote: > Erratum: > replace CH₄ ≈(ε=0.5±0.002%) PlanckMass/ProtonMass = αGproton > with CH₄ ≈(ε=0.5±0.002%) PlanckMass^2/ProtonMass^2 = αGproton > > The square term arises due to the fact that gravitation arises in the > multiplicative interaction between two masses. > > On Sun, Apr 7, 2024 at 7:51 PM James Bowery <jabow...@gmail.com> wrote: > >> >> >> On Sat, Apr 6, 2024 at 2:29 PM Matt Mahoney <mattmahone...@gmail.com> >> wrote: >> >>> One problem with estimating the size of a proton from the size of the >>> universe is that it implies that the proton or one of the constants it is >>> derived from isn't constant. >>> >> >> And this same problem applies to 2ƛₑCH₄ ≈(ε=0.81±0.15%) H₀⁻¹c >> CH₄ = 2^(2^(2^(2^2-1)-1)-1)-1 (+3+7+127) >> CH₄ ≈ 2^(2^(2^(2^2-1)-1)-1)-1 >> (not methane of course) >> >> But not to: >> CH₄ ≈(ε=0.5±0.002%) PlanckMass/ProtonMass = αGproton >> >> ƛₑ² = "quantum metric" = Compton Area of the electron (see below abstract) >> >> Interestingly, the Planck Area is increasingly viewed as more fundamental >> than the Planck Length -- in large part due to its relationship to >> information theoretic concerns such as you point out in the problematic >> relationship to the "Age of the Universe". >> >> >>> Universal semiclassical equations based on the quantum metric for a >>> two-band system >>> <https://journals.aps.org/prb/abstract/10.1103/PhysRevB.104.134312>C. >>> Leblanc, G. Malpuech, and D. D. Solnyshkov >>> Phys. Rev. B 104, 134312 – Published 26 October 2021 >>> ABSTRACT >>> We derive semiclassical equations of motion for an accelerated wave >>> packet in a two-band system. We show that these equations can be formulated >>> in terms of the static band geometry described by the quantum metric. We >>> consider the specific cases of the Rashba Hamiltonian with and without a >>> Zeeman term. The semiclassical trajectories are in full agreement with the >>> ones found by solving the Schrödinger equation. This formalism successfully >>> describes the adiabatic limit and the anomalous Hall effect traditionally >>> attributed to Berry curvature. It also describes the opposite limit of >>> coherent band superposition, giving rise to a spatially oscillating >>> *Zitterbewegung* motion, and all intermediate cases. At k=0, such a >>> wave packet exhibits a circular trajectory in real space, with its radius >>> given by the *square root of the quantum metric*. This quantity appears >>> as a *universal length scale*, providing a geometrical origin of the >>> Compton wavelength. The quantum metric semiclassical approach could be >>> extended to an arbitrary number of bands. >> >> >> >> ------------------------------------------ Artificial General Intelligence List: AGI Permalink: https://agi.topicbox.com/groups/agi/Teaac2c1a9c4f4ce3-M12e2ecff3b6449c73574d2c5 Delivery options: https://agi.topicbox.com/groups/agi/subscription
