Basic Information

Professional Memberships

• The Physical Society of Japan
• 理論天文学宇宙物理学懇談会
• Japan Gravitational-Wave Community B 会員
• 日本 Square Kilometre Array コンソーシアム
• International Society on General Relativity and Gravitation

Academic Degree

• Science(Kyoto University)
• Science(Kyoto University)

Research History

• From Apr. 2014, To Mar. 2017

  Department of Physics, Tokyo Institute of Technology, JSPS Research Fellowships for Young Scientists (PD)
• From Apr. 2012, To Mar. 2014

  Laboratoire APC, Université Paris Diderot, Researcher JSPS Postdoctoral Fellowship for Research Abroad

Language of Instruction

• Japanese

ID,URL

• J-Global ID

  201701019991852720

• External link

  http://db.tohoku.ac.jp/whois/e_detail/dad5f3b8858c3d60f56a6197d273eda4.html

researchmap URL

• https://researchmap.jp/7000020971

Research

Research Topics, Overview of the research

• Research Topics

  Cosmology and Gravitation

• Overview of the research

  After almost 100 years passed from the foundation of the general relativity by A.Einstein, it was finally reported in February 2016 that we have detected gravitational waves whose existences were first predicted by the general relativity. Gravitational waves are a sort of ripples in spacetime which is one of physical consequences in the general relativity where spacetime itself is dynamical. The observation of gravitational waves strongly support the existence of dynamics of spacetime and then the theory of gravity and related topics must be central focuses in the coming decades.
  
  On the other hand, many cosmological observations such as cosmic microwave background and type-Ia supernova indicate that the universe is acceleratedly expanding. However suppose that gravitational force is always attractive, the expansion speed of the universe will slow down since the gravitational force will attract the spacetime. Therefore the fact that the universe has experienced a stage of accelerated expansion would imply that gravitational force could be repulsive at least on cosmologically large scales, which in turn might be an indication that the theory of gravity is modified from that of the general relativity.
  
  To reveal the fundamental law of gravity in our universe and test it by means of various observations, we are developing non-linear and/or non-perturbative analytical methods beyond linear perturbation theory trying to find unknown theoretical predictions from theories of gravity by invoking those methods.

Research Interests

• Theory of gravity
• Cosmology

Research Areas

• Natural sciences, Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

Papers

• Nonlinear superhorizon perturbation and nonlinear gauge transformation

  Yuichi Takamizu; Atsushi Naruko; Misao Sasaki

  RESCEU Symposium on General Relativity and Gravitation, JGRG 22, 2012

  
• Beyond fin formalism

  Atsushi Naruko; Yu-Ichi Takamizu; Misao Sasaki

  Proceedings of the 21st Workshop on General Relativity and Gravitation in Japan, JGRG 2011, 2011

  
• Gradient expansion approach to multi-field ination

  Yuichi Takamizu; Atsushi Naruko; Misao Sasaki

  Proceedings of the 21st Workshop on General Relativity and Gravitation in Japan, JGRG 2011, 2011

  
• Gauge invariant second order boltzman equation

  Atsushi Naruko; Cyril Pitrou; Koyama Kazuya; Misao Sasaki

  Proceedings of the 20th Workshop on General Relativity and Gravitation in Japan, JGRG 2010, 2010

  
• Open inflation in string landscape

  Daisuke Yamauchi; Andrei Linde; Misao Sasaki; Takahiro Tanaka; Atsushi Naruko

  Proceedings of the 18th Workshop on General Relativity and Gravitation in Japan, JGRG 2008, 2008

  
• Axion cloud decay due to the axion-photon conversion with multi-pole background magnetic fields

  Yusuke Sakurai; Chul-Moon Yoo; Atsushi Naruko; Daisuke Yamauchi

  Journal of Cosmology and Astroparticle Physics, 01 Apr. 2024

  
• Resolving a spacetime singularity with field transformations

  Atsushi Naruko; Chul-Moon Yoo; Misao Sasaki

  Progress of Theoretical and Experimental Physics, 2021

  
• Could the black hole singularity be a field singularity?

  Guillem Domènech; Atsushi Naruko; Misao Sasaki; Christof Wetterich

  International Journal of Modern Physics D, 01 Feb. 2020

  
• The effect of anisotropic stress and non-adiabatic pressure perturbations on the evolution of the comoving curvature perturbation

  Atsushi Naruko; Antonio Enea Romano; Misao Sasaki; Sergio Andrés Vallejo-Pena

  Classical and Quantum Gravity, 2020

  
• Progress of code development: 2nd-order Einstein-Boltzmann solver for CMB anisotropy

  Takashi Hiramatsu; Ryo Saito; Atsushi Naruko; Misao Sasaki

  JGRG 2014 - Proceedings of the 24th Workshop on General Relativity and Gravitation in Japan, 2014

  
• No smooth spacetime in Lorentzian quantum cosmology and trans-Planckian physics

  Hiroki Matsui; Shinji Mukohyama; Atsushi Naruko

  Physical Review D, 09 Feb. 2023

  
• Testing the non-circularity of the spacetime around Sagittarius A* with orbiting pulsars

  Yohsuke Takamori; Atsushi Naruko; Yusuke Sakurai; Keitaro Takahashi; Daisuke Yamauchi; Chul-Moon Yoo

  Publications of the Astronomical Society of Japan, 07 Mar. 2022, Peer-reviewed

  
• DeWitt boundary condition is consistent in Hořava-Lifshitz quantum gravity

  Hiroki Matsui; Shinji Mukohyama; Atsushi Naruko

  Physics Letters B, Jul. 2022

  Access this paper :

  
• 28aSL-2 Disformal invariance of nonlinear cosmological perturbations and its multi-field extension

  Watanabe Yuki; Naruko Atsushi; Sasaki Misao

  Meeting Abstracts of the Physical Society of Japan, 2015

  
• Unified approach to secondary effects on the CMB B-mode polarization

  Toshiya Namikawa; Atsushi Naruko; Ryo Saito; Atsushi Taruya; Daisuke Yamauchi

  Journal of Cosmology and Astroparticle Physics, 01 Oct. 2021

  
• On Lorentz-invariant spin-2 theories

  Atsushi Naruko; Rampei Kimura; Daisuke Yamauchi

  Physical Review D, Dec. 2018

  
• Stable cosmological solutions in degenerate theory of gravity

  Ryotaro Kase; Rampei Kimura; Atsushi Naruko; Daisuke Yoshida

  Physics Letters B, Aug. 2018, Peer-reviewed

  
• Extended vector-tensor theories

  Rampei Kimura; Atsushi Naruko; Daisuke Yoshida

  JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, Jan. 2017, Peer-reviewed

  
• Gravitational scalar-tensor theory

  Atsushi Naruko; Daisuke Yoshida; Shinji Mukohyama

  CLASSICAL AND QUANTUM GRAVITY, May 2016, Peer-reviewed

  
• Derivative-dependent metric transformation and physical degrees of freedom

  Guillem Domènech; Shinji Mukohyama; Ryo Namba; Atsushi Naruko; Rio Saitou; Yota Watanabe

  Physical Review D - Particles, Fields, Gravitation and Cosmology, 13 Oct. 2015, Peer-reviewed

  
• Derivative-dependent metric transformation and physical degrees of freedom

  Guillem Domenech; Shinji Mukohyama; Ryo Namba; Atsushi Naruko; Rio Saitou; Yota Watanabe

  PHYSICAL REVIEW D, Oct. 2015, Peer-reviewed

  
• Cosmological disformal invariance

  Guillem Domenech; Atsushi Naruko; Misao Sasaki

  JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, Oct. 2015, Peer-reviewed

  Access this paper :

  
• Multi-disformal invariance of non-linear primordial perturbations

  Yuki Watanabe; Atsushi Naruko; Misao Sasaki

  EPL, Aug. 2015, Peer-reviewed

  Access this paper :

  
• Probing small-scale non-Gaussianity from anisotropies in acoustic reheating

  Atsushi Naruko; Atsuhisa Ota; Masahide Yamaguchi

  JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, May 2015, Peer-reviewed

  
• Anisotropic inflation reexamined: upper bound on broken rotational invariance during inflation

  Atsushi Naruko; Eiichiro Komatsu; Masahide Yamaguchi

  JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, Apr. 2015, Peer-reviewed

  
• Geodesic curve-of-sight formulae for the cosmic microwave background: a unified treatment of redshift, time delay, and lensing

  Ryo Saito; Atsushi Naruko; Takashi Hiramatsu; Misao Sasaki

  JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, Oct. 2014, Peer-reviewed

  
• Cosmology in rotation-invariant massive gravity with non-trivial fiducial metric

  David Langlois; Shinji Mukohyama; Ryo Namba; Atsushi Naruko

  CLASSICAL AND QUANTUM GRAVITY, Sep. 2014, Peer-reviewed

  
• Bouncing cosmologies in massive gravity on de Sitter

  David Langlois; Atsushi Naruko

  Classical and Quantum Gravity, 01 Oct. 2013, Peer-reviewed

  
• Second-order Boltzmann equation: gauge dependence and gauge invariance

  Atsushi Naruko; Cyril Pitrou; Kazuya Koyama; Misao Sasaki

  CLASSICAL AND QUANTUM GRAVITY, Aug. 2013, Peer-reviewed

  
• Beyond δn formalism

  Atsushi Naruko; Yu-Ichi Takamizu; Misao Sasaki

  Progress of Theoretical and Experimental Physics, Apr. 2013, Peer-reviewed

  
• Cosmological solutions of massive gravity on de Sitter

  David Langlois; Atsushi Naruko

  CLASSICAL AND QUANTUM GRAVITY, Oct. 2012, Peer-reviewed

  
• A general proof of the equivalence between the delta N and covariant formalisms

  A. Naruko

  EPL, Jun. 2012, Peer-reviewed

  
• Evolutionary effects in one-bubble open inflation for string landscape

  D. Yamauchi; A. Linde; A. Naruko; M. Sasaki; T. Tanaka

  12th Marcel Grossmann Meeting on Recent Dev. in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories - Proc. of the MG 2009 Meeting on General Relativity, 2012, Peer-reviewed

  
• Open inflation in the landscape

  Daisuke Yamauchi; Andrei Linde; Atsushi Naruko; Misao Sasaki; Takahiro Tanaka

  PHYSICAL REVIEW D, Aug. 2011, Peer-reviewed

  
• Conservation of the nonlinear curvature perturbation in generic single-field inflation

  Atsushi Naruko; Misao Sasaki

  CLASSICAL AND QUANTUM GRAVITY, Apr. 2011, Peer-reviewed

  
• Skewness in CMB temperature fluctuations from curved cosmic (super-) strings

  Daisuke Yamauchi; Yuuiti Sendouda; Chul-Moon Yoo; Keitaro Takahashi; Atsushi Naruko; Misao Sasaki

  JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, May 2010, Peer-reviewed

  
• Non-Gaussianity in the Cosmic Microwave Background temperature fluctuations from cosmic (super-)strings

  Keitaro Takahashi; Atsushi Naruko; Yuuiti Sendouda; Daisuke Yamauchi; Chul-Moon Yoo; Misao Sasaki

  JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, Oct. 2009, Peer-reviewed

  
• Large Non-Gaussianity from Multi-Brid Inflation

  Atsushi Naruko; Misao Sasaki

  PROGRESS OF THEORETICAL PHYSICS, Jan. 2009, Peer-reviewed

  

Misc.

• Ostrogradsky mode in scalar-tensor theories with higher-order derivative couplings to matter

  Atsushi Naruko; Ryo Saito; Norihiro Tanahashi; Daisuke Yamauchi

  Sep. 2022

  
• 特集：「摂動論を考える」

  佐々木 節; 成子 篤

  数理科学, Sep. 2016

  

Presentations

• On Lorentz-invariant massive spin-2 theories

  NARUKO Atsushi

  Winter Mini Workshop on Gravity and Cosmology, Jan. 2019, Invited

  
• 縮退理論と計量の変換と宇宙論

  成子 篤

  新学術領域「加速宇宙」合同コアミーティング, Dec. 2018

  
• ベクトル場とベクトル型ゆらぎと宇宙論

  成子 篤

  第七回観測的宇宙論ワークショップ, Nov. 2018, Invited

  
• Degenerate theory and its applications to cosmology

  NARUKO Atsushi

  JCAP-CGRRA 2018, Jun. 2018, Invited

  
• New massive spin-2 theories

  NARUKO Atsushi

  Essential next steps for gravity and cosmology, Jun. 2018

  
• 最近の観測結果を考慮した暗黒エネルギーモデル

  成子 篤

  日本物理学会第 73 回年次大会, Mar. 2018

  
• Stable cosmological solutions in extended vector-tensor theory

  成子 篤

  重力・宇宙論研究会 2018, Mar. 2018

  
• Extended vector-tensor theory

  34th Pacific Coast Gravity Meeting, Mar. 2018

  
• Long-wavelength perturbations around homogeneous but anisotropic spacetime

  YKIS2018a Symposium, Feb. 2018

  
• Stable cosmological solutions in extended vector-tensor theory

  Kasoku symposium 2018, Feb. 2018

  
• GW 170817 以降の重力理論の現状

  成子 篤

  日本SKAパルサー・突発天体研究会, Jan. 2018

  
• vGW = 1 の修正重力理論

  成子 篤

  新学術「重力波物理学・天文学:創世記」A班合宿研究会, Dec. 2017

  
• Dark energy model after detection of gravitational waves

  Issues on Large Scale Perturbations from Inflation, Oct. 2017

  
• 修正重力関連

  成子 篤

  新学術領域「加速宇宙」合同コアミーティング, Sep. 2017

  
• 宇宙論的ニ次摂動における渦度

  成子 篤

  日本物理学会 2017 年秋季大会, Sep. 2017

  
• Extended Vector-Tensor theories

  COSMO 17, Aug. 2017

  
• Extended Vector-Tensor theories

  ICGAC-XIII and IK15, Jul. 2017

  
• Dark Energy & Modified Gravity

  Rencontres du Vietnam: Cosmology 2017, Jul. 2017

  
• 一般的なスカラー・テンソル理論とその宇宙論への応用

  成子 篤

  日本物理学会第 72 回年次大会, Mar. 2017

  
• Extended Vector-Tensor theories

  新学術領域「加速宇宙」シンポジウム, Mar. 2017

  
• Extended Vector-Tensor theories

  Workshop on gravity and cosmology, Mar. 2017

  
• Extended Vector-Tensor theories

  New perspectives on cosmology, Feb. 2017

  
• Extended Vector-Tensor theories

  JGRG 26, Oct. 2016

  
• Some thoughts on Horndeski's hair

  Workshop on Particle Physics, Cosmology, and Gravitation, Sep. 2016

  
• Gravitational scalar-tensor theory

  GR 21, Jul. 2016

  
• Geodesic curve-of-sight formulae for the cosmic microwave background

  New perspective on theory and observation of large-scale structure, Jun. 2016

  
• On Horndeski’s hair

  Relativistic cosmology, May 2016

  
• Gravitational scalar-tensor theory

  New perspectives on cosmology, Jan. 2016

  
• Gravitational scalar-tensor theory

  JGRG 25, Dec. 2015

  
• Gravitational scalar-tensor theory

  2nd mini-workshop on gravity and cosmology, Oct. 2015

  
• Towards testing gravity theory with a pulsar-BH system

  パルサー・突発天体に関するミニワーク ショップ, 神戸市教育会館, Sep. 2015

  
• CMB beyond linear order

  Miniworkshop on cosmology, Dec. 2014

  
• Cosmology in rotation-invariant massive gravity with non-trivial fiducial metric

  JGRG 24, Nov. 2014

  
• Geodesic curve-of-sight formulae for the cosmic microwave background

  Relativistic Cosmology, Sep. 2014

  
• Primordial perturbations from anisotropic inflation revisited

  Mini-Workshop on Gravitation and Cosmology, Feb. 2014

  
• New conformal symmetry for gauge field

  APC mini-seminars, Nov. 2013

  
• Gauge (observer) dependence of CMB temperature anisotropies at second order

  Present and future of 2nd order CMB, Nov. 2013

  
• Second order Boltzmann equation : gauge dependence and gauge invariance

  Nishinomiya Yukawa Symposium : New Waves in Gravity and Cosmology, Dec. 2012

  
• 2nd order Boltzmann equation - gauge dependence and invariance

  Gravity and Cosmology 2012, Dec. 2012

  
• Beyond δN formalism

  Critical tests of Inflation using Non-Gaussianity, Nov. 2012

  
• Beyond δN formalism

  Japan in Paris, Oct. 2012

  
• On the equivalence between the δN and covariant formalisms

  Asia Pacific School/Workshop on Cosmology and Gravitation, Mar. 2012

  
• Beyond δN formalism

  Informal Workshop on Theoretical Cosmology, Sep. 2011

  
• Beyond δN formalism

  JGRG 21, Sep. 2011

  
• Conservation of the non-linear curvature perturbation in generic single-field inflation

  COSMO 11, Aug. 2011

  
• Conservation of the non-linear curvature perturbation in generic single-field inflation

  Cosmological Perturbation and Cosmic Microwave Background, Mar. 2011

  
• Gauge invariance of Boltzmann equation with polarization

  JGRG 20, Sep. 2010

  
• Gauge invariance of Boltzmann equation with polarization

  COSMO/CosPA 2010, Sep. 2010

  
• Gauge invariance of Boltzmann equation at second order

  YKIS symposium 2010, Jun. 2010

  
• Gauge invariance of Boltzmann equation at second order

  Gravity and Cosmology 2010, Jun. 2010

  
• Non-Gaussianity in the CMB temperature fluctuations from Cosmic Strings

  JGRG 19, Dec. 2009

  
• Non-Gaussianity in the CMB temperature fluctuations from Cosmic Strings

  COSMO 9, Sep. 2009

  
• Non-Gaussianity in the CMB temperature fluctuations from Cosmic Strings

  Challenges in Theoretical Cosmology, Sep. 2009

  
• Large non-Gaussianity from multi-brid inflation

  JGRG 18, Nov. 2008

  
• Large non-Gaussianity from multi-brid inflation

  Cosmology and Particle Astrophysics, Oct. 2008

  

Books and Other Publications

• Delta N Formalism in Cosmological Perturbation Theory

  Ali Akbar Abolhasani; Hassan Firouzjahi; Atsushi Naruko; Misao Sasaki, Joint work

  World Scientific, Jan. 2019, Not refereed

  Find Kyoto University's collection of books :

  

Awards

• Jan. 2016

  Europhysics Letters, Highlight Articles 2015
• Aug. 2015

  Europhysics Letters, Editor's Choice Articles 2015
• Feb. 2014

  井上科学振興財団, 第30回井上研究奨励賞
• Nov. 2013

  Classical and Quantum Gravity, CQG Highlights of 2012 - 2013
• Oct. 2011

  Classical and Quantum Gravity, CQG Highlights of 2010 - 2011
• May 2011

  IOP publishing, IOP select

External funds: Kakenhi

• Multimesseger Study of Heavy Dark Matter

  Grant-in-Aid for Transformative Research Areas (A)

  Transformative Research Areas, Section (II)

  Kyoto University

  村瀬 孔大

  From 19 Nov. 2020, To 31 Mar. 2025, Granted

  素粒子(理論);宇宙線(理論);宇宙物理(理論);理論天文学;ダークマター;マルチメッセンジャー;ニュートリノ;ガンマ線;ダークマターハロー;超高エネルギー宇宙線

  https://kaken.nii.ac.jp/grant/KAKENHI-PLANNED-20H05852/
• Next-generation relativistic cosmology in the era of precision observations

  Grant-in-Aid for Scientific Research (B)

  Basic Section 15010:Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

  Kyoto University

  Atsushi Naruko

  From 01 Apr. 2019, To 31 Mar. 2022, Project Closed

  相対論的宇宙論;宇宙マイクロ波背景放射;宇宙大規模構造;重力波

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-19H01891/
• 新しい重力理論の探求と修正重力理論の観測的検証に関する理論研究

  Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

  Science and Engineering

  Tohoku University;Tokyo Institute of Technology

  成子 篤

  From 01 Apr. 2016, To 31 Mar. 2018, Project Closed

  暗黒エネルギー;縮退した運動項;ベクトル場;宇宙物理

  https://kaken.nii.ac.jp/grant/KAKENHI-PUBLICLY-16H01092/
• 超精密かつ多スケール・多粒子観測時代における相対論的宇宙論の確立と宇宙像の探求

  Grant-in-Aid for Scientific Research (B)

  Basic Section 15010:Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

  Kyoto University

  成子 篤

  From 01 Apr. 2023, To 31 Mar. 2027, Granted

  相対論的宇宙論;初期宇宙論;宇宙マイクロ波背景放射;宇宙大規模構造;重力波

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-23H01171/
• 超精密かつ多スケール・多粒子観測時代における相対論的宇宙論の確立と宇宙像の探求

  Grant-in-Aid for Scientific Research (B)

  Basic Section 15010:Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

  Kyoto University

  成子 篤

  From 01 Apr. 2023, To 31 Mar. 2027, Granted

  相対論的宇宙論;初期宇宙論;宇宙マイクロ波背景放射;宇宙大規模構造;重力波

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-23K25868/

Administration

Faculty management (title, position)

• From 01 Apr. 2021

  談話会委員会委員