Zobrazeno 1 - 10
of 75
pro vyhledávání: '"Ota, Atsuhisa"'
Autor:
Ota, Atsuhisa
We study the analogy between graviton emission in a thermal radiation environment and the laser mechanism, where photons of the same momentum and polarization are amplified. Using interaction picture perturbation theory, we analyze the time evolution
Externí odkaz:
http://arxiv.org/abs/2412.20474
Autor:
Ota, Atsuhisa
We conduct a mode analysis of a general U(1)-charged first-order relativistic hydrodynamics within the framework of the effective field theory of dissipative fluids in a Minkowski background. The most general quadratic action for collective excitatio
Externí odkaz:
http://arxiv.org/abs/2410.23837
Autor:
Ota, Atsuhisa
We study the fluctuation-dissipation relation for sound waves in the cosmic microwave background (CMB), employing effective field theory (EFT) for fluctuating hydrodynamics. Treating sound waves as the linear response to thermal radiation, we establi
Externí odkaz:
http://arxiv.org/abs/2402.07623
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 radiation is described by taking the quantum thermal average of its co
Externí odkaz:
http://arxiv.org/abs/2310.19071
We present a consistent one-loop calculation for the inflationary tensor power spectrum in the presence of an excited spectator scalar field using the in-in formalism. We find that the super-horizon primordial power spectrum of the tensor mode can be
Externí odkaz:
http://arxiv.org/abs/2211.12766
The late-time nonlinear Lagrangian displacement field is highly correlated with the initial field, so reconstructing it could enable us to extract primordial cosmological information. Our previous work [1] carefully studied the displacement field rec
Externí odkaz:
http://arxiv.org/abs/2211.07960
We find several missing one-loop-order contributions in previous considerations about secondary gravitational waves induced at nonlinear order in cosmological perturbations. We consider a consistent perturbative expansion to third-order in cosmologic
Externí odkaz:
http://arxiv.org/abs/2210.17176
The inflationary 1-loop tensor power spectrum from an excited spectator scalar field is calculated. Recent studies on primordial black holes suggest that the inflationary curvature perturbation may be huge on small scales. An enhanced curvature pertu
Externí odkaz:
http://arxiv.org/abs/2209.02272
Autor:
Chen, Chao, Ota, Atsuhisa
Scalar-induced gravitational waves (SIGWs) are attracting growing attention for probing extremely short-scale scalar perturbations via gravitational wave measurements. In this paper, we investigate the SIGWs from statistically anisotropic scalar pert
Externí odkaz:
http://arxiv.org/abs/2205.07810
Autor:
Ota, Atsuhisa
Cosmic microwave background (CMB) spectral distortion from Rayleigh scattering is calculated for the first time in rigorous second-order cosmological perturbation theory. The new spectral distortion is sensitive to acoustic dissipation at $10^{-2}
Externí odkaz:
http://arxiv.org/abs/2204.08177