4 papers
Dynamical Prevention of Topological Defect Formation
Junseok Lee, Kai Murai, Kazunori Nakayama +1
Topological defects can have significant cosmological consequences, so their production must be examined carefully. It is usually assumed that topological defects are produced if t…
Resolving the QCD Axion Domain Wall Problem with a Light Axion
Junseok Lee, Kai Murai, Fuminobu Takahashi +1
We propose two novel solutions to the domain wall problem of the QCD axion by introducing a massless or light axion that also couples to gluons. The first solution applies when the…
Isotropic cosmic birefringence from string axion domain walls without cosmic strings, and DESI results
Junseok Lee, Kai Murai, Fuminobu Takahashi +1
Recently, results from the Atacama Cosmology Telescope (ACT) DR6 have shown a preference for isotropic cosmic birefringence, consistent with previous analyses based on Planck and W…
More is Different: Multi-Axion Dynamics Changes Topological Defect Evolution
Junseok Lee, Kai Murai, Fuminobu Takahashi +1
We study topological defects in multi-axion models arising from multiple Peccei-Quinn (PQ) scalars. Using a simplified two-axion system, we reveal fundamental differences in the ev…