Taruya, Atsushi, Nishimichi, Takahiro, Saito, Shun, Hiramatsu, Takashi
We study the non-linear evolution of baryon acoustic oscillations in the matter power spectrum and correlation function from the improved perturbation theory (PT). Based on the framework of...
Ando, Masaki, Kawamura, Seiji, Sato, Shuichi, Nakamura, Takashi, Tsubono, Kimio, Araya, Akito, ...
DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory), which is a future space gravitational wave antenna. DECIGO is expected...
Hiramatsu, Takashi, Taruya, Atsushi
We present a new numerical scheme to treat the non-linear evolution of cosmological power spectra. Governing equations for matter power spectra have been previously derived by a non-perturbative...
Non-linear Evolution of Matter Power Spectrum in Modified Theory of Gravity (2009)
Koyama, Kazuya, Taruya, Atsushi, Hiramatsu, Takashi
We present a formalism to calculate the non-linear matter power spectrum in modified gravity models that explain the late-time acceleration of the Universe without dark energy. Any successful...
Ando, Masaki, Kawamura, Seiji, Nakamura, Takashi, Tsubono, Kimio, Tanaka, Takahiro, Funaki, Ikkoh, ...
DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) which is a future space gravitational wave antenna. DECIGO is expected...
The Japanese space gravitational wave antenna; DECIGO (2008)
Kawamura, Seiji, Ando, Masaki, Nakamura, Takashi, Tsubono, Kimio, Tanaka, Takahiro, Funaki, Ikkoh, ...
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. DECIGO is expected to open a new window of observation for gravitational...
Sawamura, Kenji, Hiramatsu, Takashi, Ozaki, Katsuhiro, Ichinose, Ikuo, Matsui, Tetsuo
In this paper we study the lattice CP$^1$ model in (3+1) dimensions coupled with a dynamical compact U(1) gauge field. This model is an effective field theory of the $s={1 \over 2}$ antiferromagnetic...
A Closure Theory for Non-linear Evolution of Cosmological Power Spectra (2007)
Taruya, Atsushi, Hiramatsu, Takashi
We apply a non-linear statistical method in turbulence to the cosmological perturbation theory and derive a closed set of evolution equations for matter power spectra. The resultant closure equations...
Scalar perturbations in braneworld cosmology (2007)
Cardoso, Antonio, Hiramatsu, Takashi, Koyama, Kazuya, Seahra, Sanjeev S.
We study the behaviour of scalar perturbations in the radiation-dominated era of Randall-Sundrum braneworld cosmology by numerically solving the coupled bulk and brane master wave equations. We find...
Primordial perturbations from slow-roll inflation on a brane (2007)
Koyama, Kazuya, Mennim, Andrew, Rubakov, V. A., Wands, David, Hiramatsu, Takashi
In this paper we quantise scalar perturbations in a Randall-Sundrum-type model of inflation where the inflaton field is confined to a single brane embedded in five-dimensional anti-de Sitter...
Numerical study of curvature perturbations in a brane-world inflation at high-energies (2006)
Hiramatsu, Takashi, Koyama, Kazuya
We study the evolution of scalar curvature perturbations in a brane-world inflation model in a 5D Anti-de Sitter spacetime. The inflaton perturbations are confined to a 4D brane but they are coupled...
Himemoto, Yoshiaki, Taruya, Atsushi, Kudoh, Hideaki, Hiramatsu, Takashi
We discuss a robust data analysis method to detect a stochastic background of gravitational waves in the presence of non-Gaussian noise. In contrast to the standard cross-correlation (SCC) statistic...
Self-Reduction Rate of a Microtubule (2006)
Hiramatsu, Takashi, Matsui, Tetsuo, Sakakibara, Kazuhiko
We formulate and study a quantum field theory of a microtubule, a basic element of living cells. Following the quantum theory of consciousness by Hameroff and Penrose, we let the system to reduce to...
We discuss the cosmological evolution of the inflationary gravitational wave background (IGWB) in the Randall-Sundrum single-brane model. In the braneworld cosmology, in which three-dimensional...
Detecting a gravitational-wave background with next-generation space interferometers (2005)
Kudoh, Hideaki, Taruya, Atsushi, Hiramatsu, Takashi, Himemoto, Yoshiaki
Future missions of gravitational-wave astronomy will be operated by space-based interferometers, covering very wide range of frequency. Search for stochastic gravitational-wave backgrounds (GWBs) is...
Gravitational Wave Background from Neutrino-Driven Gamma-Ray Bursts (2005)
Hiramatsu, Takashi, Kotake, Kei, Kudoh, Hideaki, Taruya, Atsushi
We discuss the gravitational wave background (GWB) from a cosmological population of gamma-ray bursts (GRBs). Among various emission mechanisms for the gravitational waves (GWs), we pay a particular...
Evolution of gravitational waves in the high-energy regime of brane-world cosmology (2004)
Hiramatsu, Takashi, Koyama, Kazuya, Taruya, Atsushi
We discuss the cosmological evolution of gravitational waves (GWs) after inflation in a brane-world cosmology embedded in five-dimensional anti-de Sitter (AdS_5) bulk spacetime. In a brane-world...
Hiramatsu, Takashi, Koyama, Kazuya, Taruya, Atsushi
We study the evolution of gravitational waves(GWs) after inflation in a brane-world cosmology embedded in five-dimensional anti-de Sitter spacetime. Contrary to the standard four-dimensional results,...