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Updated: Sep 21, 2025

The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry
Published on: August 12, 2013
Symmetry of Cosmological Observables, a Mirror World Dark Sector, and the Hubble Constant
Francis-Yan Cyr-Racine1, Fei Ge2, Lloyd Knox2
1Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87106, USA.
Abstract:
We find that a uniform scaling of the gravitational free-fall rates and photon-electron scattering rate leaves most dimensionless cosmological observables nearly invariant. This result opens up a new approach to reconciling cosmic microwave background and large-scale structure observations with high values of the Hubble constant H_{0}: Find a cosmological model in which the scaling transformation can be realized without violating any measurements of quantities not protected by the symmetry. A "mirror world" dark sector allows for effective scaling of the gravitational free-fall rates while respecting the measured mean photon density today. Further model building might bring consistency with the two constraints not yet satisfied: the inferred primordial abundances of deuterium and helium.
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