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Extreme Axions Unveiled: Conclusionby@cosmological
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Extreme Axions Unveiled: Conclusion

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In this paper, researchers introduce extreme axions, exploring their impact on small-scale structure in cosmology, particularly in Ly-α forest measurements.
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This paper is available on arxiv under CC 4.0 license.

Authors:

(1) HARRISON WINCH, Department of Astronomy & Astrophysics, University of Toronto and Dunlap Institute for Astronomy and Astrophysics, University of Toronto;

(2) RENEE´ HLOZEK, Department of Astronomy & Astrophysics, University of Toronto and Dunlap Institute for Astronomy and Astrophysics, University of Toronto;

(3) DAVID J. E. MARSH, Theoretical Particle Physics and Cosmology, King’s College London;

(4) DANIEL GRIN, Haverford College;

(5) KEIR K. ROGERS, Dunlap Institute for Astronomy and Astrophysics, University of Toronto.

5. CONCLUSIONS

Extreme axions represent an interesting class of dark matter models, possessing both interesting theoretical justifications from string theory, as well as concrete cosmological observables. Previously, their one major drawback was the high computational cost of modeling the rapid field oscillations. In this work, we have introduced a new extension to the existing axionCAMB software, allowing it to compute MPS and CMB observables for extreme axion models in ∼ 7 seconds, where previous models have taken multiple days. These observables can be computed for a range of values for the axion mass, axion DM density fraction, and extreme axion starting angle, as well as a range of ordinary cosmological parameters. We achieved this rapid modeling of the extreme axions by using a modified version of axionCAMB’s fluid approximation, reconfiguring the initial conditions to allow for finely tuned starting angles, modifying the effective fluid sound speed to reflect the tachyonic growth during the oscillatory phase, and implementing an efficient lookup table of the axion background fluid variables to allow for rapid computation.