activity
20242026
collaborators

6 papers

astro-ph.CO2026

Constraining the inflaton potential with gravitational waves from oscillons

Kaloian D. Lozanov, Misao Sasaki, Jan Tränkle

Under certain conditions, the oscillating inflaton condensate filling the Universe after inflation can fragment and form so-called oscillons. These long-lived soliton-like field co…

astro-ph.CO2025

Dark matter from inflationary quantum fluctuations

Mohammad Ali Gorji, Misao Sasaki, Teruaki Suyama

We explore a scenario in which dark matter is a massive bosonic field, arising solely from quantum fluctuations generated during inflation. In this framework, dark matter exhibits…

astro-ph.CO2025

Halo Formation from Yukawa Forces in the Very Early Universe

Guillem Domènech, Derek Inman, Alexander Kusenko +1

If long-range attractive forces exist and are stronger than gravity then cosmic halo formation can begin in the radiation-dominated era. We study a simple realization of this effec…

astro-ph.CO2025

Axion-like Universal Gravitational Wave Interpretation of Pulsar Timing Array Data

Kaloian D. Lozanov, Shi Pi, Misao Sasaki +2

Formation of cosmological solitons is generically accompanied by production of gravitational waves (GWs), with a universal GW background expected at frequency scales below that of…

astro-ph.CO2025

Universal Gravitational Wave Signatures of Cosmological Solitons

Kaloian D. Lozanov, Misao Sasaki, Volodymyr Takhistov

Cosmological solitonic objects such as monopoles, cosmic strings, domain walls, oscillons and Q-balls often appear in theories of the early Universe. We demonstrate that such scena…

gr-qc2024

Crunch from AdS bubble collapse in unbounded potentials

Kaloian D. Lozanov, Misao Sasaki

We consider a scalar field theory with a Minkowski false vacuum and an unbounded (or very deep) true vacuum. We show compelling evidence that an AdS bubble of vanishing total energ…