Table of Links

• Abstract and Intro
• Methods
• Phenomenology
• Discussion and Future Work
• Conclusion
• Acknowledgments and References

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.