15 citations · 48 across the 10 of their papers we have counts for
11 papers · 1 filter
Axion Isocurvature Perturbations Survive the Scaling Evolution of Axion Domain Walls
Naoya Kitajima, Junseok Lee, Kai Murai +2
We revisit the evolution of axion domain walls seeded by inflationary fluctuations. In our previous work, we showed that such domain-wall networks retain superhorizon correlations…
Multi-field oscillons/I-balls in the Friedberg-Lee-Sirlin model
Kai Murai, Tatsuya Ogawa, Fuminobu Takahashi
We study oscillon/I-ball solutions in a real scalar version of the Friedberg-Lee-Sirlin (FLS) model. Using the multiple-scale analysis, we derive the conditions for oscillon soluti…
Sign-Flipping Axion Potentials via Kapitza-Type Modulation by Heavy Axions
Kai Murai, Fuminobu Takahashi, Kosei Tomiyama
We show that the potential of a light axion can flip sign, or even nearly vanish, as a result of coherent oscillations of a heavier axion with which it mixes. This phenomenon is an…
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…
Q-balls Under Spontaneously Broken U(1) Symmetry
Masahiro Kawasaki, Kai Murai, Fuminobu Takahashi
We study the evolution of Q-balls under a spontaneously broken global symmetry. Q-balls are stabilized by the conservation of charge, but when the symmetry is spontan…