6 papers
Spectator Composes a Gravitational Canon: Spectator-field-triggered Phase Transition During Inflation and its Anisotropic Gravitational Wave Signals
Yunjia Bao, Keisuke Harigaya
We propose a general framework in which a phase transition is triggered during cosmic inflation by the slow-roll dynamics of a spectator field. The topological defects formed at th…
Enhanced Matter Power Spectrum from Axion Kination after Big Bang Nucleosynthesis
Raymond T. Co, Nicolas Fernandez, Akshay Ghalsasi +2
Despite stringent constraints from Big Bang Nucleosynthesis (BBN) and cosmic microwave background (CMB) observations, it is still possible for well-motivated particle physics model…
Anisotropic Gravitational Waves from Anisotropic Axion Rotation
Arushi Bodas, Keisuke Harigaya, Keisuke Inomata +2
Gravitational waves (GWs) provide a powerful probe of the early universe due to their ability to free-stream across cosmic history. We study GW production in a compelling scenario…
Universal lower bound on the axion decay constant from free streaming effects
Keisuke Harigaya, Wayne Hu, Rayne Liu +1
We show that enhancement of the axion relic abundance compared to the standard misalignment contribution generically leads to the production of nonzero momentum axion modes, result…
Acoustic Misalignment Mechanism for Axion Dark Matter
Arushi Bodas, Raymond T. Co, Akshay Ghalsasi +2
A rotation in the field space of a complex scalar field corresponds to a Bose-Einstein condensation of charges. We point out that fluctuations in this rotating condensate ex…
Dynamical Solution to the Eta Problem in Spectator Field Models
Sana Elgamal, Keisuke Harigaya
We study a class of spectator field models that addresses the eta problem while providing a natural explanation for the observed slight deviation of the spectrum of curvature pertu…