activity
20072024
most citedDominance of gauge artifact in the consistency relation for the primordial bispectrum

126 citations · 1.4k across the 40 of their papers we have counts for

collaborators

40 papers

gr-qc2024

g formalism

Takahiro Tanaka, Yuko Urakawa

The formalism has been the major computational tool to study the superhorizon evolution of the scalar type perturbation sourced by scalar fields. Recently, this formalism was…

gr-qc2023★ 1 cited

Statistical anisotropy of primordial gravitational waves from generalized formalism

Takahiro Tanaka, Yuko Urakawa

In this letter, we demonstrate how to use the generalized formalism, which enables us to compute the evolution of all the large scale fluctuations, including gravitational wav…

astro-ph.CO2021★ 15 cited

New scenario of QCD axion clump formation I: Linear analysis

Naoya Kitajima, Kazuhiro Kogai, Yuko Urakawa

The QCD axion acquires the potential through the non-perturbative effect of the QCD matters around the QCD phase transition. During this period, the direct interaction between the…

astro-ph.CO2021★ 14 cited

Anisotropic separate universe and Weinberg's adiabatic mode

Takahiro Tanaka, Yuko Urakawa

In the separate universe approach, an inhomogeneous universe is rephrased as a set of glued numerous homogeneous local patches. This is the essence of the gradient expansion and th…

astro-ph.CO2020★ 38 cited

Nano-Hz gravitational wave signature from axion dark matter

Naoya Kitajima, Jiro Soda, Yuko Urakawa

We calculate the accurate spectrum of the stochastic gravitational wave background from U(1) gauge fields produced by axion dark matter. The explosive production of gauge fields so…

astro-ph.CO2020★ 48 cited

Galaxy imaging surveys as spin-sensitive detector for cosmological colliders

Kazuhiro Kogai, Kazuyuki Akitsu, Fabian Schmidt +1

Galaxy imaging surveys provide us with information on both the galaxy distribution and their shapes. In this paper, we systematically investigate the sensitivity of galaxy shapes t…