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What does cosmology teach us about non-gravitational properties of dark matter?
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Relativistic bulk rheology: From neutron star mergers to viscous cosmology
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Displacement field analysis via optimal transport: Multitracer approach to cosmological reconstruction
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Superresolution emulation of large cosmological fields with a 3D conditional diffusion model
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Cosmological dynamics of string theory axion strings
The quantum chromodynamics (QCD) axion may solve the strong CP problem and explain the dark matter (DM) abundance of our Universe. The axion was originally proposed to arise as the pseudo-Nambu-Goldstone boson of global U(1) PQ Peccei-Quinn (PQ) symmetry breaking, but axions also arise generically in string theory as zero modes of higher-dimensional gauge fields. In this work we show that string theory axions behave fundamentally differently from field theory axions in the early Universe. Field theory axions may form axion strings if the PQ phase transition takes place after inflation. In contrast, we show that string theory axions do not generically form axion strings. In special inflationary paradigms, such as D-brane inflation, string theory axion strings may form; however, their tension is parametrically larger than that of field theory axion strings. We then show that such QCD axion strings overproduce the DM abundance for all allowed QCD axion masses and are thus ruled out, except in scenarios with large warping. A loop-hole to this conclusion arises in the axiverse, where an axion string could be composed of multiple different axion mass eigenstates; a heavier eigenstate could collapse the network earlier, allowing for the QCD axion to produce the correct DM abundance and also generating observable gravitational wave signals.
Improving convolutional neural networks for cosmological fields with random permutation
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Constraining cosmological parameters with needlet internal linear combination maps. I. Analytic power spectrum formalism
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Constraining cosmological parameters with needlet internal linear combination maps. II. Likelihood-free inference on needlet internal linear combination power spectra
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Reconstructing the recombination history by combining early and late cosmological probes
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Cosmology with varying fundamental constants from hyperlight, coupled scalars
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Optical cluster cosmology with SDSS redMaPPer clusters and HSC-Y3 lensing measurements
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Intermediate mass-range particles from small scales: Nonperturbative techniques for cosmological collider physics from large-scale structure surveys
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Cosmological parameters from the joint analysis of density split and second order statistics: An emulator based on the halo occupation distribution
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Ten-parameter simulation suite for cosmological emulation beyond Λ CDM
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Reconstructing f ( T ) gravity and exploring the torsion driven warm inflationary cosmology
The current paper reports an investigation of a warm inflationary scenario in the context of f(T) gravity for a spatially flat FLRW universe. In our model, inflation is driven purely by the torsional sector of f(T) gravity, without introducing any additional scalar fields. We focus on the high dissipative regime (R >> 1), reconstruct the Hubble parameter as a function of the e-folding number N, and derive the slow-roll parameters ε 1 (N) and ε 2 (N). The study has encapsulated the dynamics of inflation and its duration under strong dissipation. The dissipative coefficient Γ is modeled with a temperature-dependent power-law form, linking the inflationary dynamics to thermal corrections and the particle content of the early universe. The analysis has affirmed that the torsion-induced energy density ρ T successfully transitions to radiation energy density ρ rad , facilitating a graceful exit from inflation. Finally, we have validated our model by comparing the scalar spectral index and tensor-to-scalar ratio with Planck 2018 results, demonstrating consistency within observational bounds. Additionally, it is verified that the thermal domination condition T * /H > 1 and the torsion dominance condition ρ T /ρ rad > 1 are satisfied.
Status of the Dark Energy Spectroscopic Instrument (DESI) and Year 1 Cosmology results
The Dark Energy Spectroscopic Instrument (DESI) will measure the effect of dark energy on the expansion of the universe. It will obtain optical spectra for tens of millions of galaxies and quasars, constructing a 3D map spanning the nearby universe to 11 billion light years. The DESI Survey is being conducted on the Mayall 4-meter telescope at Kitt Peak National Observatory. DESI is supported by the Department of Energy Office of Science to perform this Stage IV dark energy measurement using baryon acoustic oscillations and other techniques that rely on spectroscopic measurements. I will discuss the status of the Dark Energy Spectroscopic Instrument (DESI) survey and present our Year 1 Baryon Acoustic Oscillation measurements.
Probing Reheating Cosmology with Dark-Sector Searches: Cosmic Millicharged Background
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