A Z_N-symmetric multi-copy dark-QCD axion, broken by single-sector reheating, yields natural phantom-crossing dark energy with dark-pion DM in a viable parameter window.
Cosmology with Ultra-light Pseudo-Nambu-Goldstone Bosons
8 Pith papers cite this work. Polarity classification is still indexing.
abstract
We explore the cosmological implications of an ultra-light pseudo-Nambu-Goldstone boson. With global spontaneous symmetry breaking scale $f \simeq 10^{18}$ GeV and explicit breaking scale comparable to MSW neutrino masses, $M \sim 10^{-3}$ eV, such a field, which acquires a mass $m_\phi \sim M^2/f \sim H_0$, would have become dynamical at recent epochs and currently dominate the energy density of the universe. The field acts as an effective cosmological constant for several expansion times and then relaxes into a condensate of coherent non-relativistic bosons. Such a model can reconcile dynamical estimates of the density parameter, $\Omega_m \sim 0.2$, with a spatially flat universe, and can yield an expansion age $H_0 t_0 \simeq 1$ while remaining consistent with limits from gravitational lens statistics.
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Imaginary wormholes and the IDB imply that towers of BPS EFT instantons generate infinitely many superpotential terms that break non-invertible axion shift symmetries in N=1 axiverse models.
Full DES data from SN+BAO+3x2pt yields w0=-0.84, wa=-0.44 with 2.2σ deviation from ΛCDM; adding DESI+CMB reaches 3.0σ while 3x2pt improves figure of merit by ~10%.
An analytic bound on axion parameters in thawing quintessence is derived independently of initial conditions and used with cosmological observations plus quantum gravity constraints to exclude large regions of axion dark energy parameter space.
Photon-axion conversion near Kerr black holes produces dimming of photon spectral luminosity that increases with black hole spin, magnetic field strength, and photon-axion coupling, most efficiently at high frequencies.
Effective phantom dark energy is a background-level reconstruction that does not imply fundamental pathologies such as ghost instabilities or null energy condition violation by the underlying stress tensor.
A review of string-inspired dynamical dark energy models claiming compatibility with DESI's hints of evolving dark energy under swampland constraints.
A mini-review of axion phenomenology showing how light bosons can account for dark matter, drive cosmic acceleration, or contribute to relativistic backgrounds in the early and late Universe.
citing papers explorer
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Natural Phantom Dark Energy from a $\mathbb{Z}_N$--Axion
A Z_N-symmetric multi-copy dark-QCD axion, broken by single-sector reheating, yields natural phantom-crossing dark energy with dark-pion DM in a viable parameter window.
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Non-invertible symmetries in the axiverse, and the imaginary wormholes
Imaginary wormholes and the IDB imply that towers of BPS EFT instantons generate infinitely many superpotential terms that break non-invertible axion shift symmetries in N=1 axiverse models.
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Constraints on Dynamical Dark Energy from Multiple Probes in the Full Dark Energy Survey
Full DES data from SN+BAO+3x2pt yields w0=-0.84, wa=-0.44 with 2.2σ deviation from ΛCDM; adding DESI+CMB reaches 3.0σ while 3x2pt improves figure of merit by ~10%.
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Bounding axion dark energy
An analytic bound on axion parameters in thawing quintessence is derived independently of initial conditions and used with cosmological observations plus quantum gravity constraints to exclude large regions of axion dark energy parameter space.
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Dimming of Photon Ring due to Photon-Axion Conversion around Kerr Black Holes
Photon-axion conversion near Kerr black holes produces dimming of photon spectral luminosity that increases with black hole spin, magnetic field strength, and photon-axion coupling, most efficiently at high frequencies.
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Effective Phantom Dark Energy: What Cosmological Reconstruction Does and Does Not Imply
Effective phantom dark energy is a background-level reconstruction that does not imply fundamental pathologies such as ghost instabilities or null energy condition violation by the underlying stress tensor.
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Breaking Free from the Swampland of Impossible Universes through the DESI Portal
A review of string-inspired dynamical dark energy models claiming compatibility with DESI's hints of evolving dark energy under swampland constraints.
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Axions as Dark Matter, Dark Energy, and Dark Radiation
A mini-review of axion phenomenology showing how light bosons can account for dark matter, drive cosmic acceleration, or contribute to relativistic backgrounds in the early and late Universe.