Axions in Japan

Session

Parallel session - Gravity III

12 Nov 2025, 14:00

Lecture Hall (Kavli IPMU)

24. Domain walls induced by domain walls in a two axion system

Junseok Lee

12/11/2025, 14:00

We show that heavy axion domain walls induce domain walls of the QCD axion through a mixing between the heavy axion and the QCD axion, even when the pre-inflationary initial condition is assumed for the QCD axion. The induced domain walls arise because the effective θ parameter changes across the heavy axion domain walls, shifting the potential minimum of the QCD axion. When the heavy axion...

25. The Gravitational-Wave Symphony of Axion-like Particles

Pankaj Saha

12/11/2025, 14:20

The early Universe offers a unique window into fundamental physics far beyond the reach of terrestrial experiments. In this talk, I will discuss how ultra-light axionlike scalar fields—ubiquitous in extensions of the Standard Model---can leave observable imprints through stochastic gravitational waves (GWs) generated by parametric resonance in the post-inflationary era. Using lattice...

44. Constraints on extended axion structures from the lensing of fast radio bursts

Kuan-Yen Chou

12/11/2025, 14:40

Axions are hypothetical pseudoscalar particles that have been regarded as promising dark matter (DM) candidates. On the other hand, extended compact objects such as axion stars, which are supported by gravity and axion self interactions, may have also been formed in the early Universe and comprise part of DM. In this work, we consider the lensing of electromagnetic signals from distant sources...

43. Spinoptics in the presence of axion-like particles (cancelled)

Tomoki Takeuchi

In curved spacetime, the trajectory of a light ray is described by a geodesic under the geometric optics approximation.However, this approximation is valid only locally and is not justified int the all spacetime regions.If it breaks down, the polarization of light can affect its propagation.In this presentation, we consider light propagating through an axion field in spinoptics...