934 citations · 12.9k across the 205 of their papers we have counts for
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Efficient diagrammatic computation method for higher order correlation functions of local type primordial curvature perturbations
Shuichiro Yokoyama, Teruaki Suyama, Takahiro Tanaka
We present a new efficient method for computing the non-linearity parameters of the higher order correlation functions of local type curvature perturbations in inflation models hav…
Primordial Non-Gaussianity in Multi-Scalar Inflation
Shuichiro Yokoyama, Teruaki Suyama, Takahiro Tanaka
We give a concise formula for the non-Gaussianity of the primordial curvature perturbation generated on super-horizon scales in multi-scalar inflation model without assuming slow-r…
Primordial Non-Gaussianity in Multi-Scalar Slow-Roll Inflation
Shuichiro Yokoyama, Teruaki Suyama, Takahiro Tanaka
We analyze the non-Gaussianity for primordial curvature perturbations generated in multi-scalar slow-roll inflation model including the model with non-separable potential by making…
Wronskian Formulation of the Spectrum of Curvature Perturbations
Shuichiro Yokoyama, Takahiro Tanaka, Misao Sasaki +1
We present a new formulation for the evaluation of the primordial spectrum of curvature perturbations generated during inflation, using the fact that the Wronskian of the scalar fi…
Exact Wave Propagation in a Spacetime with a Cosmic String
Teruaki Suyama, Takahiro Tanaka, Ryuichi Takahashi
We present exact solutions of the massless Klein-Gordon equation in a spacetime in which an infinite straight cosmic string resides. The first solution represents a plane wave ente…
A New delta N Formalism for Multi-Component Inflation
Hyun-Chul Lee, Misao Sasaki, Ewan D. Stewart +2
The delta N formula that relates the final curvature perturbation on comoving slices to the inflaton perturbation on flat slices after horizon crossing is a powerful and intuitive…
Application of the Separate Universe Approach to Preheating
Takahiro Tanaka, Bruce Bassett
The dynamics of preheating after inflation has not been clearly understood yet.In particular, the issue of the generation of metric perturbations during preheating on super-horizon…
Stable Operation of a 300-m Laser Interferometer with Sufficient Sensitivity to Detect Gravitational-Wave Events within our Galaxy
Masaki Ando, the TAMA collaboration
TAMA300, an interferometric gravitational-wave detector with 300-m baseline length, has been developed and operated with sufficient sensitivity to detect gravitational-wave events…
A comment on trans-Planckian physics in inflationary universe
Takahiro Tanaka
There are several works searching for a clue of trans-Planckian physics on the primordial density perturbation spectrum. Here we would like to point out an important aspect which h…
Density Distribution and Shape of Galactic Dark Halo Can be Determined by Low Frequency Gravitational Waves ?
Kunihito Ioka, Takahiro Tanaka, Takashi Nakamura
Under the assumption that the Milky Way's dark halo consists of primordial black hole MACHOs (PBHMACHOs), the mass density of the halo can be measured by the low frequency gravitat…
CMB in Open Inflation
Andrei Linde, Misao Sasaki, Takahiro Tanaka
The possibility to have an infinite open inflationary universe inside a bubble of a finite size is one of the most interesting realizations extensively discussed in the literature.…
Spectrum of Cosmological Perturbations in the One-Bubble Open Universe
Jaume Garriga, Xavier Montes, Misao Sasaki +1
The spectrum of cosmological perturbations in the context of the one-bubble open inflation model is discussed, taking into account fluctuations of the metric. We find that, quite g…
Low frequency gravitational waves from black hole MACHO binaries
Kunihito Ioka, Takahiro Tanaka, Takashi Nakamura
The intensity of low frequency gravitational waves from black hole MACHO binaries is studied. First we estimate the gravitational wave background produced by black hole MACHO binar…
Black Hole Binary Formation in the Expanding Universe --- Three Body Problem Approximation ---
Kunihito Ioka, Takeshi Chiba, Takahiro Tanaka +1
We study black hole MACHO binary formation through three-body interactions in the early universe at s. The probability distribution functions of the eccentricity and…
Gravitational Waves from Coalescing Black Hole MACHO Binaries
Takashi Nakamura, Misao Sasaki, Takahiro Tanaka +1
If MACHOs are black holes of mass about 0.5 solar mass, they must have been formed in the early universe when the temperature was about 1 GeV. We estimate that in this case in our…
Wall fluctuation modes and tensor CMB anisotropy in open inflation models
Misao Sasaki, Takahiro Tanaka, Yoshihiro Yakushige
We calculate the spectrum of large angle cosmic microwave background (CMB) anisotropies due to quantum fluctuations of the gravitational wave modes in one-bubble open inflation mod…
The Spectrum of Gravitational Wave Perturbations in the One-Bubble Open Inflationary Universe
Takahiro Tanaka, Misao Sasaki
We give the initial spectrum of quantized gravitational waves in the context of the one-bubble open inflationary universe scenario. In determining the quantum state after the bubbl…
Quantum fluctuations and CMB anisotropies in one-bubble open inflation models
Kazuhiro Yamammoto, Misao Sasaki, Takahiro Tanaka
We first develop a method to calculate a complete set of mode functions which describe the quantum fluctuations generated in one-bubble open inflation models. We consider two class…
Large Angle CMB Anisotropy in an Open Universe in the One-Bubble Inflationary Scenario
Kazuhiro Yamamoto, Misao Sasaki, Takahiro Tanaka
We consider an alternative scenario of inflation which can account for a spatially open universe. It is similar to the old inflation in which the bubble nucleation occurs in the se…
Probability Distribution of Primordial Angular Momentum and Formation of Massive Black Holes
Hajime Susa, Misao Sasaki, Takahiro Tanaka
We consider the joint probability distribution function for the mass contrast and angular momentum of over-density regions on the proto- galactic scale and investigate the formatio…