10 papers
The Challenge of Detecting Quantum Nature of Gravitational Waves
Yu Miyauchi, Hidetoshi Omiya, Atsuhisa Ota +2
We investigate whether squeezing can provide an observable signature of quantum gravitational waves. Because a realistic detector couples only to a particular wave-packet mode, squ…
CMB Spectral Distortion Anisotropies from Acoustic Damping with primordial non-Gaussianity
Jens Chluba, Atsuhisa Ota, Nicola Bartolo
In this paper, we evaluate the precise distortion source and transfer functions caused by mixing of blackbodies of different temperatures using the recently developed frequency hie…
Ultraviolet Structure of Real-time Gravitational Wave Linear Response in a Resonant Scalar Field
Han Lai, Atsuhisa Ota
We study the real-time linear response of gravitational waves in a time-dependent resonant scalar field in a Minkowski background. In the Schwinger-Keldysh formalism, we develop an…
Real-time Gravitational Wave Response in Thermal Spinning fields
Atsuhisa Ota, Hui-Yu Zhu, Yuhang Zhu
We study how the spin content of the thermal plasmas affects the propagation of gravitational waves in a radiation-dominated universe. As a simple but representative setup, we cons…
Collective Properties of Gravitational Perturbations in Thermal Environments on a Dynamical Background
Atsuhisa Ota
A thermal plasma dresses soft gauge fields, turning them into collective modes with a plasmon gap and Landau damping. In this paper, we ask whether a thermal radiation plasma does…
Graviton stimulated emission in squeezed vacuum states
Atsuhisa Ota, Yuhang Zhu
We study the dynamics of gravitons in a squeezed vacuum state under a thermal radiation background. Unlike traditional treatments that rely on the Boltzmann equation, we employ the…
Cosmological stimulated emission
Atsuhisa Ota
We study stimulated emission and absorption of gravitons in a squeezed vacuum state immersed in a thermal radiation bath. Employing one-loop interaction-picture perturbation theory…
Mode analysis of Nambu-Goldstone modes in U(1) charged first-order relativistic viscous hydrodynamics
Atsuhisa Ota
We conduct a mode analysis of a general -charged first-order relativistic hydrodynamics within the framework of effective field theory for dissipative fluids in flat Minkowsk…
Fluctuation-dissipation relation in cosmic microwave background
Atsuhisa Ota
We study the fluctuation-dissipation relation for sound waves in the cosmic microwave background (CMB), employing effective field theory (EFT) for fluctuating hydrodynamics. Treati…
One-loop thermal radiation exchange in gravitational wave power spectrum
Atsuhisa Ota, Misao Sasaki, Yi Wang
The radiation-dominated universe is a key ingredient of the standard Big Bang cosmology. Radiation comprises numerous quantum elementary particles, and the macroscopic behavior of…