The 5th workshop on Symmetry and Structure of the Universe (SSU 2026 Busan)

Session

S8

26 Aug 2026, 13:30

Conveners

S8

• Kwang Sik Jeong (Pusan National University)

4. Isocurvature Induced Gravitational Waves at Pulsar Timing Arrays

Peizhi Du (University of Science and Technology of China)

26/08/2026, 13:30

The standard cosmological model (ΛCDM model) assumes adiabatic initial conditions for primordial density perturbations. However, many new physics scenarios can deviate from this assumption and generate isocurvature perturbations across a wide range of scales. In this talk, I will discuss how isocurvature can induce gravitational waves at second order in perturbation theory. Moreover, Pulsar...

9. Quest for a Consistent Phase Transition Explanation of the PTA Signal

Sudhakantha Girmohanta (Institute for Basic Science, CTPU-PTC, Korea)

26/08/2026, 14:10

The discovery of a nano-Hz stochastic gravitational wave background by Pulsar Timing Array (PTA) collaborations can be interpreted as arising from a strongly supercooled phase transition in a nearly conformal dark sector. I will present a concrete model for this phase transition, and show that the strong supercooling it requires generically dilutes any pre-existing baryon asymmetry and dark...