Particle Theory and Cosmology Group
Department of Physics
Tohoku University

Research Interest:
Particle physics (beyond the standard model), Particle cosmology (inflation, dark matter, baryogenesis, etc.)

- I would like to understand how the Universe was born and evolved into the present state, namely, how inflation occurred, how the universe was reheated after inflation, how the dark matter as well as the baryon asymmetry were created, whether there is large non-Gaussianity in the density perturbations or not. These issues cannot be answered without knowledge about the physics at very high energies. So I am also interested in physics beyond the standard model, and the interplay between the cosmology and particle physics.

Papers: inspire, arXiv

Recent ones:

Cosmological abundance of the QCD axion coupled to hidden photons
N. Kitajima, T. Sekiguchi, F. Takahashi

The ALP miracle revisited
R. Daido, F. Takahashi, W. Yin

Adiabatic suppression of the axion abundance and isocurvature due to coupling to hidden monopoles
M. Kawasaki, F. Takahashi, M. Yamada

[arXiv:1705.04796Phys.Lett. B773 (2017) 179-185
Neutrino CP phases from Sneutrino Chaotic Inflation
K. Nakayama, F. Takahashi, T. T. Yanagida

[arXiv:1704.00155Phys.Lett. B772 (2017) 127-129
The sign of the dipole–dipole potential by axion exchange
R. Daido, F. Takahashi

[arXiv:1702.03284JCAP 1705 (2017) 044
The ALP miracle: unified inflaton and dark matter
R. Daido, F. Takahashi, W. Yin

[arXiv:1610.00631Phys.Lett. B768 (2017) 30-37
Gauge Coupling Unification with Hidden Photon, and Minicharged Dark Matter
R. Daido, F. Takahashi, N. Yokozaki

[arXiv:1608.04092Phys.Lett. B765 (2017) 293-299
Dark Matter in Axion Landscape
R. Daido, T. Kobayashi, F. Takahashi

[arXiv:1607.04294JCAP 1608 (2016) 056
Cosmological Perturbations of Axion with a Dynamical Decay Constant
T. Kobayashi, F. Takahashi

[arXiv:1606.05552JHEP 1608 (2016) 044
Topological Defects and nano-Hz Gravitational Waves in Aligned Axion Models
T. Higaki, K. S. Jeong, N. Kitajima, T. Sekiguchi, F. Takahashi

[arXiv:1604.07145Phys.Lett. B760 (2016) 486-493
Diphoton excess from hidden U(1) gauge symmetry with large kinetic mixing
F. Takahashi, M. Yamada, N. Yokozaki

[arXiv:1603.07601Phys.Lett. B760 (2016) 329-334
Renormalization Group Improved Higgs Inflation with a Running Kinetic Term
F. Takahashi, R. Takahashi

[arXiv:1603.02090JHEP 1606 (2016) 150
Quality of the Peccei-Quinn symmetry in the Aligned QCD Axion and Cosmological Implications
T. Higaki, K. S. Jeong, N. Kitajima, F. Takahashi

[arXiv:1601.00192Phys.Lett. B757 (2016) 32-38
Viable Chaotic Inflation as a Source of Neutrino Masses and Leptogenesis
K. Nakayama, F. Takahashi, T. T. Yanagida

Awards :
Young Scientist Award of the Physical Society of Japan (2011)
Inoue Research Award (2012)
The 2013 Young Scientist award in theoretical particle physics

Career :
2005 Postdoc Fellow at ICRR, University of Tokyo
2005 - 2007: Postdoc Fellow at DESY Theory Group
2007 - 2011 January: Project Assistant professor at IPMU, University of Tokyo
2011 - 2017: Associate professor at Department of Physics, Tohoku University
2018 - Present: Professor at Department of Physics, Tohoku University

Recent Talks :

  • Japan Physical Society annual meeting at Osaka Univ. (in Japanese)

Lectures :
Relativistic quantum mechanics (2011-2013)
Cosmology (2011-2017)
QFT-I (2014-2017)
Summer school at Yoyogi Olympic Center 2017 (

Activities of our group:

Postal Address :
Particle Theory and Cosmology Group, Department of Physics, Tohoku University,
6-3, aza-Aoba, Aramaki, Aoba-ku,
Sendai 980-8578, Japan