Axion Fragmentation on the Lattice

Abstract

We analyze the phenomenon of axion fragmentation when an axion field rolls over many oscillations of a periodic potential. This is particularly relevant for the case of relaxion, in which fragmentation provides the necessary energy dissipation to stop the field evolution. We compare the results of a linear analysis with the ones obtained from a classical lattice simulation, finding an agreement in the stopping time of the zero mode between the two within an $\mathcal{O}(1)$ difference. We finally speculate on the generation of bubbles with different VEVs of the axion field, and discuss their cosmological consequences.

27 pages + appendices

References in corpus (9)

• Ultralight scalars as cosmological dark matter
• Monodromy in the CMB: Gravity Waves and String Inflation
• The Powers of Monodromy
• F-term Axion Monodromy Inflation
• D7-Brane Chaotic Inflation
• Towards Universal Axion Inflation and Reheating in String Theory
• Relaxation from particle production
• Chiral Anomaly, Schwinger Effect, Euler-Heisenberg Lagrangian, and application to axion inflation
• Dynamics of Domain Walls for Split and Runaway Potentials