Details of the Researcher

PHOTO

Fuminobu Takahashi
Section
Graduate School of Science
Job title
Professor
Degree

Professional Memberships 1

  • 日本物理学会

Research Interests 6

  • Early Universe Theory

  • axion

  • バリオン非対称性

  • インフレーション

  • ダークマター

  • particle cosmology

Research Areas 1

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

Awards 4

  1. Yukawa-Kimura prize

    2024/09　Particle Cosmology and Early Universe

  2. 素粒子メダル奨励賞

    2013　素粒子論グループ

  3. 第五回井上リサーチアウォード

    2013　井上科学振興財団

  4. Award for the Encouragement of Young Physicists

    2011

Papers 74

  1. Kilobyte Cosmic Birefringence from ALP domain walls Peer-reviewed

    Fuminobu Takahashi, Wen Yin

    Journal of Cosmology and Astroparticle Physics　2021　(4)　2021/04

    DOI： 10.1088/1475-7516/2021/04/007 　

    eISSN： 1475-7516

  2. XENON1T Excess from Anomaly-Free Axionlike Dark Matter and Its Implications for Stellar Cooling Anomaly Peer-reviewed

    Fuminobu Takahashi, Masaki Yamada, Wen Yin

    PHYSICAL REVIEW LETTERS　125　(16)　2020/10

    DOI： 10.1103/PhysRevLett.125.161801 　

    ISSN： 0031-9007

    eISSN： 1079-7114

  3. Relic abundance of dark photon dark matter Peer-reviewed

    Prateek Agrawal, Naoya Kitajima, Matthew Reece, Toyokazu Sekiguchi, Fuminobu Takahashi

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics　801　2020/02/10

    DOI： 10.1016/j.physletb.2019.135136 　

    ISSN： 0370-2693

  4. Resolving the QCD axion domain wall problem with a light axion

    Junseok Lee, Kai Murai, Fuminobu Takahashi, Wen Yin

    Journal of High Energy Physics　2026/01/19

    DOI： 10.1007/JHEP01(2026)124 　

  5. Primordial black hole formation via inverted bubble collapse Peer-reviewed

    Kai Murai, Kodai Sakurai, Fuminobu Takahashi

    Journal of High Energy Physics　2025/07/03

    DOI： 10.1007/JHEP07(2025)065 　

  6. Stability of domain walls with inflationary fluctuations under potential bias, and gravitational wave signatures

    Naoya Kitajima, Junseok Lee, Fuminobu Takahashi, Wen Yin

    Journal of Cosmology and Astroparticle Physics　2025/07/01

    DOI： 10.1088/1475-7516/2025/07/053 　

  7. Thermal production of axions from heavy Higgs bosons

    Kodai Sakurai, Fuminobu Takahashi

    Journal of High Energy Physics　2025/04/24

    DOI： 10.1007/JHEP04(2025)187 　

  8. QCD axion dark matter from level crossing with refined adiabatic condition

    Kai Murai, Yuma Narita, Fuminobu Takahashi, Wen Yin

    Journal of High Energy Physics　2025/04/16

    DOI： 10.1007/JHEP04(2025)124 　

  9. More is different: multi-axion dynamics changes topological defect evolution

    Junseok Lee, Kai Murai, Fuminobu Takahashi, Wen Yin

    Journal of Cosmology and Astroparticle Physics　2025/04/01

    DOI： 10.1088/1475-7516/2025/04/002 　

  10. Induced domain walls of QCD axion, and gravitational waves

    Junseok Lee, Kai Murai, Fuminobu Takahashi, Wen Yin

    Journal of Cosmology and Astroparticle Physics　2024　(10)　038-038　2024/10/01

    Publisher: IOP Publishing

    DOI： 10.1088/1475-7516/2024/10/038 　

    eISSN： 1475-7516

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    Abstract We show that heavy axion domain walls induce domain walls of the QCD axion through a mixing between the heavy axion and the QCD axion, even when the pre-inflationary initial condition is assumed for the QCD axion. The induced domain walls arise because the effective θ parameter changes across the heavy axion domain walls, shifting the potential minimum of the QCD axion. When the heavy axion domain walls collapse, the induced QCD axion domain walls collapse as well. This novel mechanism for producing the QCD axions can explain dark matter even with the axion decay constant as small as 𝒪(109) GeV. In particular, this scenario requires domain wall collapse near the QCD crossover, potentially accounting for the stochastic gravitational wave background suggested by recent pulsar timing array observations, including NANOGrav. Using this mechanism, it is also possible to easily create induced domain walls for string axions or axions with a large decay constant, which would otherwise be challenging. We also comment on the implications for cosmic birefringence using induced axion domain walls.

  11. Bubble misalignment mechanism for axions

    Junseok Lee, Kai Murai, Fuminobu Takahashi, Wen Yin

    Journal of Cosmology and Astroparticle Physics　2024　(05)　122-122　2024/05/01

    Publisher: IOP Publishing

    DOI： 10.1088/1475-7516/2024/05/122 　

    eISSN： 1475-7516

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    Abstract We study the dynamics of axions at first-order phase transitions in non-Abelian gauge theories. When the duration of the phase transition is short compared to the timescale of the axion oscillations, the axion dynamics is similar to the trapped misalignment mechanism. On the other hand, if this is not the case, the axions are initially expelled from the inside of the bubbles, generating axion waves on the outside. Analogous to the Fermi acceleration, these axions gain energy by repeatedly scattering off the bubble walls. Once they acquire enough energy, they can enter the bubbles. If the axion oscillations are relevant only inside the bubbles during the phase transition, the axion abundance is significantly enhanced compared to models where the axion mass is either constant or varies continuously as a function of temperature. The increase in axion abundance depends on the axion mass, the duration of the phase transition, and the bubble wall velocity. This mechanism results in a spatially inhomogeneous distribution of axions, which could lead to the formation of axion miniclusters. It has potential implications for the formation of oscillons/I-balls, axion warm dark matter, cosmic birefringence, and the production of dark photons.

  12. Primordial origin of supermassive black holes from axion bubbles

    Kentaro Kasai, Masahiro Kawasaki, Naoya Kitajima, Kai Murai, Shunsuke Neda, Fuminobu Takahashi

    Journal of Cosmology and Astroparticle Physics　2024　(05)　092-092　2024/05/01

    Publisher: IOP Publishing

    DOI： 10.1088/1475-7516/2024/05/092 　

    eISSN： 1475-7516

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    Abstract We study a modification of the primordial black hole (PBH) formation model from axion bubbles.We assume that the Peccei-Quinn scalar rolls down in the radial direction from a large field value to the potential minimum during inflation, which suppresses the axion fluctuations and weakens the clustering of PBHs on large scales.We find that the modified model can produce a sufficient number of PBHs that seed the supermassive black holes while avoiding the observational constraints from isocurvature perturbations and angular correlation of the high-redshift quasars.

  13. Gravitational waves from domain wall collapse, and application to nanohertz signals with QCD-coupled axions

    Naoya Kitajima, Junseok Lee, Kai Murai, Fuminobu Takahashi, Wen Yin

    Physics Letters B　851　138586-138586　2024/04

    Publisher: Elsevier BV

    DOI： 10.1016/j.physletb.2024.138586 　

    ISSN： 0370-2693

  14. Hadrophobic axion from a GUT

    Fuminobu Takahashi, Wen Yin

    Physical Review D　109　(3)　2024/02/28

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevd.109.035024 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  15. Dissipation of axion energy via the Schwinger and Witten effects Peer-reviewed

    Kwang Sik Jeong, Shota Nakagawa, Fuminobu Takahashi, Masaki Yamada

    Physical Review D　2024/01/16

    DOI： 10.1103/PhysRevD.109.015014 　

  16. QCD axion hybrid inflation

    Yuma Narita, Fuminobu Takahashi, Wen Yin

    Journal of Cosmology and Astroparticle Physics　2023　(12)　039-039　2023/12/01

    Publisher: IOP Publishing

    DOI： 10.1088/1475-7516/2023/12/039 　

    eISSN： 1475-7516

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    Abstract When the inflaton is coupled to the gluon Chern-Simons term for successful reheating, mixing between the inflaton and the QCD axion is generally expected given the solution of the strong CP problem by the QCD axion. This is particularly natural if the inflaton is a different, heavier axion.We propose a scenario in which the QCD axion plays the role of the inflaton by mixing with heavy axions. In particular, if the energy scale of inflation is lower than the QCD scale, a hybrid inflation is realized where the QCD axion plays the role of the inflaton in early stages. We perform detailed numerical calculations to take account of the mixing effects. Interestingly, the initial misalignment angle of the QCD axion, which is usually a free parameter, is determined by the inflaton dynamics. It is found to be close to π in simple models. This is the realization of the pi-shift inflation proposed in previous literature, and it shows that QCD axion dark matter and inflation can be closely related. The heavy axion may be probed by future accelerator experiments.

  17. Can baryon asymmetry be explained by a large initial value before inflation?

    Kai Murai, Fuminobu Takahashi, Masaki Yamada, Wen Yin

    Physical Review D　108　(8)　2023/10/18

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevd.108.083518 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  18. Clustering of primordial black holes from QCD axion bubbles

    Kentaro Kasai, Masahiro Kawasaki, Naoya Kitajima, Kai Murai, Shunsuke Neda, Fuminobu Takahashi

    Journal of Cosmology and Astroparticle Physics　2023　(10)　049-049　2023/10/01

    Publisher: IOP Publishing

    DOI： 10.1088/1475-7516/2023/10/049 　

    eISSN： 1475-7516

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    Abstract We study the clustering of primordial black holes (PBHs) and axion miniclusters produced in the model proposed to explain the LIGO/Virgo events or the seeds of the supermassive black holes (SMBHs) in ref. [1]. It is found that this model predicts large isocurvature perturbations due to the clustering of PBHs and axion miniclusters, from which we obtain stringent constraints on the model parameters. Specifically, for the axion decay constant  fa = 1016 GeV, which potentially accounts for the seeds of the SMBHs, the PBH fraction in dark matter should be fPBH ≲ 7 × 10-10. Assuming that the mass of PBHs increases by more than a factor of 𝒪(10) due to accretion, this is consistent with the observed abundance of SMBHs. On the other hand, for  fa = 1017 GeV required to produce PBHs of masses detected in the LIGO/Virgo, the PBH fraction should be fPBH ≲ 6 × 10-8, which may be too small to explain the LIGO/Virgo events, although there is a significant uncertainty in calculating the merger rate in the presence of clustering.

  19. QCD axion: A unique player in the axiverse with mixings

    Kai Murai, Fuminobu Takahashi, Wen Yin

    Physical Review D　108　(3)　2023/08/29

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevd.108.036020 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  20. Quantum decay of scalar and vector boson stars and oscillons into gravitons Peer-reviewed

    Kazunori Nakayama, Fuminobu Takahashi, Masaki Yamada

    Journal of Cosmology and Astroparticle Physics　2023/08/01

    DOI： 10.1088/1475-7516/2023/08/058 　

    ISSN： 1475-7516

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    <jats:title>Abstract</jats:title><jats:p>We point out that a soliton such as an oscillon or boson star inevitably decays into gravitons through gravitational interactions. These decay processes exist even if there are no apparent self-interactions of the constituent field, scalar or vector, since they are induced by gravitational interactions. Hence, our results provide a strict upper limit on the lifetime of oscillons and boson stars including the dilute axion star. We also calculate the spectrum of the graviton background from decay of solitons.</jats:p>

  21. Stability of domain wall network with initial inflationary fluctuations and its implications for cosmic birefringence

    Diego Gonzalez, Naoya Kitajima, Fuminobu Takahashi, Wen Yin

    Physics Letters B　843　137990-137990　2023/08

    Publisher: Elsevier BV

    DOI： 10.1016/j.physletb.2023.137990 　

    ISSN： 0370-2693

  22. Resonant production of dark photons from axions without a large coupling

    Naoya Kitajima, Fuminobu Takahashi

    Physical Review D　107　(12)　2023/06/15

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevd.107.123518 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  23. Axion dark matter from first-order phase transition, and very high energy photons from GRB 221009A

    Shota Nakagawa, Fuminobu Takahashi, Masaki Yamada, Wen Yin

    Physics Letters B　839　137824-137824　2023/04

    Publisher: Elsevier BV

    DOI： 10.1016/j.physletb.2023.137824 　

    ISSN： 0370-2693

  24. Early dark energy by a dark Higgs field and axion-induced nonthermal trapping

    Shota Nakagawa, Fuminobu Takahashi, Wen Yin

    Physical Review D　107　(6)　2023/03/14

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevd.107.063016 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  25. Power spectrum of domain-wall network, and its implications for isotropic and anisotropic cosmic birefringence Peer-reviewed

    Naoya Kitajima, Fumiaki Kozai, Fuminobu Takahashi, Wen Yin

    Journal of Cosmology and Astroparticle Physics　2022　(10)　043-043　2022/10/01

    Publisher: IOP Publishing

    DOI： 10.1088/1475-7516/2022/10/043 　

    eISSN： 1475-7516

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    Abstract Recently, based on a novel analysis of the Planck satellite data, a hint of a uniform rotation of the polarization of cosmic microwave background photons, called isotropic cosmic birefringence, has been reported. The suggested rotation angle of polarization of about 0.2–0.4 degrees is close to the fine-structure constant, α ≃ 1/137 rad ≃ 0.42 deg. Interestingly, this coincidence can be naturally explained over a very wide parameter range by the domain walls of axion-like particles. Furthermore, the axion-like particle domain walls predict not only isotropic cosmic birefringence but also anisotropic one that reflects the spatial distribution of the axion-like particle field on the last scattering surface. In this paper, we perform lattice simulations of the formation and evolution of domain walls in the expanding universe and obtain for the first time the two-point correlation function and power spectrum of the scalar field that constitutes the domain walls. We find that for initial fluctuations at subhorizon scales, the power spectrum is roughly consistent with analytical predictions based on random wall distributions. However, there is some excess at scales corresponding to the Hubble radius. Applying our results to the anisotropic cosmic birefringence, we predict the power spectrum of the rotation angles induced by the axion-like particle domain walls for the similar initial condition, and show that it is within reach of future observations of the cosmic microwave background.

  26. Gravitational production of dark photon dark matter with mass generated by the Higgs mechanism Peer-reviewed

    Takanori Sato, Fuminobu Takahashi, Masaki Yamada

    Journal of Cosmology and Astroparticle Physics　2022　(08)　022-022　2022/08/01

    Publisher: IOP Publishing

    DOI： 10.1088/1475-7516/2022/08/022 　

    eISSN： 1475-7516

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    Abstract We study the gravitational production of dark photon dark matter during inflation, when dark photons acquire mass by the Higgs mechanism. In the previous study, it was assumed that the dark photon has a Stückelberg mass, or a mass generated by the Higgs mechanism with a sufficiently heavy Higgs boson. In this paper we consider a case in which the Higgs boson is not fully decoupled; the Higgs field changes its vacuum expectation value after inflation. Then, the dark photon mass also changes with time after inflation, and the time evolution of the longitudinal mode is different from the case with a Stückelberg mass. Consequently, the spectrum of the dark photon energy density can have two peaks at an intermediate scale and a small scale. We show that the dark photon can explain the dark matter if its current mass is larger than 6 μeV × (HI/1014 GeV)-4 and smaller than 0.8 GeV × (HI/1014 GeV)-3/2, with HI being the Hubble parameter during inflation. A higher mass is required if one considers a larger gauge coupling constant. The result for the Stückelberg mass can be reproduced in the limit of a small gauge coupling constant. We also comment on the constraints set by various conjectures in quantum gravity theory.

  27. Anomaly-free axion dark matter in three Higgs doublet model and its phenomenological implications

    Kodai Sakurai, Fuminobu Takahashi

    Journal of High Energy Physics　2022　(7)　2022/07/20

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/jhep07(2022)124 　

    eISSN： 1029-8479

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    Abstract We study phenomenological implications of an axion that arises as a pseudo Nambu-Goldstone boson due to the spontaneous breaking of anomaly-free global flavor symmetry. One interesting possibility for such anomaly-free axion to explain dark matter (DM) is when it has a mass of order keV and an intermediate scale decay constant, since it can be explored through direct search experiments, X-ray observations, various stellar cooling processes, and the misalignment mechanism naturally explains the DM abundance. As a concrete renormalizable model of such axion, we consider an extended Higgs sector with global flavor symmetry, which consists of three Higgs doublet fields and three singlet Higgs fields with U(1)B−L charges. We identify viable parameter regions that satisfy theoretical bounds on the Higgs potential and various experimental limits on this model, and evaluate the mass spectra of the axion and extra Higgs bosons. We find that even an anomaly-free axion can generally couple to photons through mixing with CP-odd Higgs, and that its strength depends on the vacuum expectation values of the Higgs doublets as well as the axion mass. As a result, the ratios of the vacuum expectation values of the Higgs doublets are tightly constrained to satisfy the X-ray constraints. We show the favored parameter region where axion DM explains the XENON1T excess. We also demonstrate that the axion-electron coupling is correlated with the extra Higgs boson masses and mixing angles for CP-even Higgs bosons. Thus, if the axion is detected in future observations, the extra Higgs boson masses and the coupling of the standard model-like Higgs boson with the weak gauge bosons are restricted. This is a good example of the synergy between searches for the axion DM and the BSM around the electroweak scale.

  28. Singlet extensions and W boson mass in light of the CDF II result Peer-reviewed

    Kodai Sakurai, Fuminobu Takahashi, Wen Yin

    Physics Letters B　137324-137324　2022/07

    Publisher: Elsevier BV

    DOI： 10.1016/j.physletb.2022.137324 　

    ISSN： 0370-2693

  29. Cosmological implications of n ≈ 1 in light of the Hubble tension Peer-reviewed

    Fuminobu Takahashi, Wen Yin

    Physics Letters B　830　137143-137143　2022/07

    Publisher: Elsevier BV

    DOI： 10.1016/j.physletb.2022.137143 　

    ISSN： 0370-2693

  30. Nonthermally trapped inflation by tachyonic dark photon production Peer-reviewed

    Naoya Kitajima, Shota Nakagawa, Fuminobu Takahashi

    Physical Review D　105　(10)　2022/05/11

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevd.105.103011 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  31. Cosmological effects of Peccei-Quinn symmetry breaking on QCD axion dark matter Peer-reviewed

    Kwang Sik Jeong, Kohei Matsukawa, Shota Nakagawa, Fuminobu Takahashi

    Journal of Cosmology and Astroparticle Physics　2022　(03)　026-026　2022/03/01

    Publisher: IOP Publishing

    DOI： 10.1088/1475-7516/2022/03/026 　

    eISSN： 1475-7516

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    Abstract We study cosmological effects of explicit Peccei-Quinn breaking on the QCD axion dark matter. We find that the axion abundance decreases or increases significantly depending on the initial position, even for a tiny Peccei-Quinn breaking that satisfies the experimental bound of the neutron electric dipole measurements. If the axion first starts to oscillate around a wrong vacuum and if it gets trapped there until the false vacuum disappears due to non-perturbative QCD effects, its abundance increases significantly and is independent of the decay constant  fa, as first pointed out in ref. [1]. Thus, the axion produced by the trapping mechanism can explain dark matter even when the decay constant is close to the lower limit due to stellar cooling arguments. On the other hand, if the axion starts to oscillate about a potential minimum close to the low-energy vacuum, its abundance is significantly reduced because of the adiabatic suppression mechanism. This relaxes the upper limit of the axion window to large values of fa. We also discuss how the axionic isocurvature perturbation is affected by the Peccei-Quinn breaking term, and show that it can be suppressed in both regimes. In particular, the isocurvature bound on the inflation scale is relaxed by many orders of magnitudes for fa ≳ 1011 GeV compared to the conventional scenario.

  32. Cosmic Birefringence Triggered by Dark Matter Domination Peer-reviewed

    Shota Nakagawa, Fuminobu Takahashi, Masaki Yamada

    Physical Review Letters　127　(18)　2021/10/28

    Publisher: American Physical Society (APS)

    DOI： 10.1103/physrevlett.127.181103 　

    ISSN： 0031-9007

    eISSN： 1079-7114

  33. Challenges for heavy QCD axion inflation Peer-reviewed

    Fuminobu Takahashi, Wen Yin

    Journal of Cosmology and Astroparticle Physics　2021　(10)　057-057　2021/10/01

    Publisher: IOP Publishing

    DOI： 10.1088/1475-7516/2021/10/057 　

    eISSN： 1475-7516

  34. Gravitational waves and dark radiation from dark phase transition: Connecting NANOGrav pulsar timing data and hubble tension Peer-reviewed

    Yuichiro Nakai, Motoo Suzuki, Fuminobu Takahashi, Masaki Yamada

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics　816　2021/05/10

    DOI： 10.1016/j.physletb.2021.136238 　

    ISSN： 0370-2693

  35. Trapping effect for QCD axion dark matter Peer-reviewed

    Shota Nakagawa, Fuminobu Takahashi, Masaki Yamada

    JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS　(5)　2021/05

    DOI： 10.1088/1475-7516/2021/05/062 　

    ISSN： 1475-7516

  36. What if ALP dark matter for the XENON1T excess is the inflaton Peer-reviewed

    Fuminobu Takahashi, Masaki Yamada, Wen Yin

    JOURNAL OF HIGH ENERGY PHYSICS　(1)　2021/01

    DOI： 10.1007/JHEP01(2021)152 　

    ISSN： 1029-8479

  37. Primordial black holes from QCD axion bubbles Peer-reviewed

    Naoya Kitajima, Fuminobu Takahashi

    Journal of Cosmology and Astroparticle Physics　2020　(11)　2020/11

    DOI： 10.1088/1475-7516/2020/11/060 　

    eISSN： 1475-7516

  38. QCD axion window and false vacuum Higgs inflation Peer-reviewed

    Hiroki Matsui, Fuminobu Takahashi, Wen Yin

    Journal of High Energy Physics　2020　(5)　2020/05/01

    DOI： 10.1007/JHEP05(2020)154 　

    ISSN： 1126-6708

    eISSN： 1029-8479

  39. Stochastic axion dark matter in axion landscape Peer-reviewed

    Shota Nakagawa, Fuminobu Takahashi, Wen Yin

    JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS　2020　(5)　004-004　2020/05

    DOI： 10.1088/1475-7516/2020/05/004 　

    ISSN： 1475-7516

    eISSN： 1475-7516

  40. Stochastic inflation with an extremely large number of e-folds Peer-reviewed

    Naoya Kitajima, Yuichiro Tada, Fuminobu Takahashi

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics　800　2020/01/10

    DOI： 10.1016/j.physletb.2019.135097 　

    ISSN： 0370-2693

  41. Hidden monopole dark matter via axion portal and its implications for direct detection searches, beam-dump experiments, and the H <inf>0</inf> tension Peer-reviewed

    Ryuji Daido, Shu Yu Ho, Fuminobu Takahashi

    Journal of High Energy Physics　2020　(1)　2020/01/01

    DOI： 10.1007/JHEP01(2020)185 　

    ISSN： 1126-6708

    eISSN： 1029-8479

  42. QCD axion on hilltop by a phase shift of π Peer-reviewed

    Fuminobu Takahashi, Wen Yin

    Journal of High Energy Physics　2019　(10)　2019/10/01

    DOI： 10.1007/JHEP10(2019)120 　

    ISSN： 1126-6708

    eISSN： 1029-8479

  43. QCD axion window and low-scale inflation Peer-reviewed

    Takahashi, Fuminobu, Yin, Wen, Guth, Alan H.

    Phys.Rev.D　98　(1)　015042-015042　2018/08/01

    DOI： 10.1103/PhysRevD.98.015042 　

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    We show that the upper bound of the classical QCD axion window can be significantly relaxed for low-scale inflation. If the Gibbons-Hawking temperature during inflation is lower than the QCD scale, the initial QCD axion misalignment angle follows the Bunch-Davies distribution. The distribution is peaked at the strong CP conserving minimum if there is no other light degree of freedom contributing to the strong CP phase. As a result, the axion overproduction problem is significantly relaxed even for an axion decay constant larger than $10^{12}$GeV. We also provide concrete hilltop inflation models where the Hubble parameter during inflation is comparable to or much smaller than the QCD scale, with successful reheating taking place via perturbative decays or dissipation processes.

  44. Probing axion-photon coupling from the resonant conversion of QCD axion and ALP dark matter

    Shu-Yu Ho, Ken'Ichi Saikawa, Fuminobu Takahashi

    Proceedings of the 14th Patras Workshop on Axions, WIMPs and WISPs, PATRAS 2018　29-32　2018

    Publisher: Verlag Deutsches Elektronen-Synchrotron

    DOI： 10.3204/DESY-PROC-2018-03/Ho_Shu-Yu 　

  45. Space Gravitational Wave Antenna DECIGO and B-DECIGO

    Kawamura, Seiji, Nakamura, Takashi, Ando, Masaki, Seto, Naoki, Akutsu, Tomotada, Funaki, Ikkoh, Ioka, Kunihito, K, a, Nobuyuki, Kawano, Isao, Musha, Mitsuru, Nakazawa, Kazuhiro, Sato, Shuichi, Takashima, Takeshi, Tanaka, Takahiro, Tsubono, Kimio, Yokoyama, Jun'ichi, Agatsuma, Kazuhiro, Aoyanagi, Koh-suke, Arai, Koji, Araya, Akito, Aritomi, Naoki, Asada, Hideki, Aso, Yoichi, Chen, Dan, Chiba, Takeshi, Ebisuzaki, Toshikazu, Eguchi, Satoshi, Ejiri, Yumiko, Enoki, Motohiro, Eriguchi, Yoshiharu, Fujimoto, Masa-Katsu, Fujita, Ryuichi, Fukushima, Mitsuhiro, Futamase, Toshifumi, Gondo, Rina, Harada, Tomohiro, Hashimoto, Tatsuaki, Hayama, Kazuhiro, Hikida, Wataru, Himemoto, Yoshiaki, Hirabayashi, Hisashi, Hiramatsu, Takashi, Hong, Feng-Lei, Horisawa, Hideyuki, Hosokawa, Mizuhiko, Ichiki, Kiyotomo, Ikegami, Takeshi, Inoue, Kaiki T, Ishihara, Hideki, Ishikawa, Takehiko, Ishizaki, Hideharu, Ito, Hiroyuki, Itoh, Yousuke, Izumi, Kiwamu, Kanemura, Shinya, Kawashima, Nobuki, Kawazoe, Fumiko, Kishimoto, Naoko, Kiuchi, Kenta, Kobayashi, Shiho, Kohri, Kazunori, Koizumi, Hiroyuki, Kojima, Yasufumi, Kokeyama, Keiko, Kokuyama, Wataru, Kotake, Kei, Kozai, Yoshihide, Kunimori, Hiroo, Kuninaka, Hitoshi, Kuroda, Kazuaki, Kuroyanagi, Sachiko, Maeda, Kei-ichi, Matsuhara, Hideo, Matsumoto, Nobuyuki, Michimura, Yuta, Miyakawa, Osamu, Miyamoto, Umpei, Miyoki, Shinji, Morimoto, Mutsuko Y, Morisawa, Toshiyuki, Moriwaki, Shigenori, Mukohyama, Shinji, Nagano, Shigeo, Nakamura, Kouji, Nakano, Hiroyuki, Nakao, Kenichi, Nakasuka, Shinichi, Nakayama, Yoshinori, Nishida, Erina, Nishizawa, Atsushi, Niwa, Yoshito, Noumi, Taiga, Obuchi, Yoshiyuki, Ohishi, Naoko, Ohkawa, Masashi, Okada, Kenshi, Okada, Norio, Okutomi, Koki, Oohara, Kenichi, Sago, Norichika, Saijo, Motoyuki, Saito, Ryo, Sakagami, Masaaki, Sakai, Shin-ichiro, Sakata, Shihori, Sasaki, Misao, Sato, Takashi, Shibata, Masaru, Shibata, Kazunori, Shimo-oku, Ayumi, Shinkai, Hisaaki, Shoda, Ayaka, Somiya, Kentaro, Sotani, Hajime, Suemasa, Aru, Sugiyama, Naoshi, Suwa, Yudai, Suzuki, Rieko, Tagoshi, Hideyuki, Takahashi, Fuminobu, Takahashi, Kakeru, Takahashi, Keitaro, Takahashi, Ryutaro, Takahashi, Ryuichi, Takahashi, Hirotaka, Akiteru, Takamori, Takano, Tadashi, Tanaka, Nobuyuki, Taniguchi, Keisuke, Taruya, Atsushi, Tashiro, Hiroyuki, Torii, Yasuo, Toyoshima, Morio, Tsujikawa, Shinji, Ueda, Akitoshi, Ueda, Ken-ichi, Ushiba, Takafumi, Utashima, Masayoshi, Wakabayashi, Yaka, Yagi, Kent, Yamamoto, Kazuhiro, Yamazaki, Toshitaka, Yoo, Chul-Moon, Yoshida, Shijun, Yoshino, Taizoh

    International Journal of Modern Physics D　0　(ja)　2018

    DOI： 10.1142/S0218271818450013 　

    ISSN： 0218-2718

  46. Domain wall formation from level crossing in the axiverse Peer-reviewed

    Ryuji Daido, Naoya Kitajima, Fuminobu Takahashi

    PHYSICAL REVIEW D　92　(6)　2015/09

    DOI： 10.1103/PhysRevD.92.063512 　

    ISSN： 1550-7998

    eISSN： 1550-2368

  47. Degenerate spectrum in the neutrino mass anarchy with Wishart matrices and implications for 0νββ and δcP Peer-reviewed

    Kwang Sik Jeong, Naoya Kitajima, Fuminobu Takahashi

    Physical Review D - Particles, Fields, Gravitation and Cosmology　91　(11)　2015/06/16

    Publisher: American Physical Society

    DOI： 10.1103/PhysRevD.91.113010 　

    ISSN： 1550-2368 1550-7998

  48. 26aSD-5 Domain Wall Formation from Level Crossing in the Axiverse

    Daido Ryuji, Kitajima Naoya, Takahashi Fuminobu

    Meeting Abstracts of the Physical Society of Japan　70　18-18　2015

    Publisher: The Physical Society of Japan (JPS)

    DOI： 10.11316/jpsgaiyo.70.2.0_18 　

    ISSN： 2189-079X

  49. Topological Higgs inflation: Origin of Standard Model criticality Peer-reviewed

    Yuta Hamada, Kin-ya Oda, Fuminobu Takahashi

    PHYSICAL REVIEW D　90　(9)　2014/11

    DOI： 10.1103/PhysRevD.90.097301 　

    ISSN： 1550-7998

    eISSN： 1550-2368

  50. Running spectral index from large-field inflation with modulations revisited Peer-reviewed

    Michael Czerny, Takeshi Kobayashi, Fuminobu Takahashi

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics　735　176-180　2014/07/30

    Publisher: Elsevier

    DOI： 10.1016/j.physletb.2014.06.018 　

    ISSN： 0370-2693

  51. Resonant conversions of QCD axions into hidden axions

    Naoya Kitajima, Fuminobu Takahashi

    JGRG 2014 - Proceedings of the 24th Workshop on General Relativity and Gravitation in Japan　1　49-62　2014

    Publisher: University of Tokyo, Kavli Institute for Physics and Mathematics of the Universe, KIPMU

  52. Testing the origin of primordial perturbation: Use of bi and tri-spectrum Peer-reviewed

    T. Suyama, K. Ichikawa, M. Kawasaki, K. Nakayama, T. Sekiguchi, F. Takahashi, T. Takahashi, T. Tanaka, Y. Watanabe, M. Yamaguchi, J. Yokoyama, S. Yokoyama

    RESCEU Symposium on General Relativity and Gravitation, JGRG 22　111303-　2012

  53. Adiabatic solution to the Polonyi/moduli problem Peer-reviewed

    Kazunori Nakayama, Fuminobu Takahashi, Tsutomu T. Yanagida

    Physical Review D - Particles, Fields, Gravitation and Cosmology　84　(12)　2011/12/28

    DOI： 10.1103/PhysRevD.84.123523 　

    ISSN： 1550-7998 1550-2368

  54. Non-Gaussianity from curvatons revisited Peer-reviewed

    Masahiro Kawasaki, Takeshi Kobayashi, Fuminobu Takahashi

    Physical Review D - Particles, Fields, Gravitation and Cosmology　84　(12)　2011/12/08

    DOI： 10.1103/PhysRevD.84.123506 　

    ISSN： 1550-7998 1550-2368

  55. Gravitational waves from Q-balls in gravity mediation

    Takashi Hiramatsu, Fuminobu Takahashi, Masahide Yamaguchi

    Proceedings of the 20th Workshop on General Relativity and Gravitation in Japan, JGRG 2010　302-306　2010

  56. Dark matter and cosmic-ray anomalies

    Takahashi Fuminobu

    Soryushiron Kenkyu Electronics　117　(6)　F7-F13　2010

    Publisher: Soryushiron Kenkyu Editorial Office

    DOI： 10.24532/soken.117.6_F7 　

    ISSN： 0371-1838

    More details Close

    After giving a review of recent cosmic-ray observations such as PAMELA, ATIC/PPB-BETS, Fermi and H.E.S.S, I explain what kind of conditions must be met if the PAMELA/Fermi excesses are due to dark matter. Finally I will give one dark matter model based on a Wino LSP with a tiny R-parity violation.

  57. Conformal supersymmetry breaking in vectorlike gauge theories Peer-reviewed

    K. I. Izawa, Fuminobu Takahashi, T. T. Yanagida, Kazuya Yonekura

    Physical Review D - Particles, Fields, Gravitation and Cosmology　80　(8)　2009/10/15

    DOI： 10.1103/PhysRevD.80.085017 　

    ISSN： 1550-7998 1550-2368

  58. DECIGO: The Japanese space gravitational wave antenna Peer-reviewed

    S. Sato, S. Kawamura, M. Ando, T. Nakamura, K. Tsubono, A. Araya, I. Funaki, K. Ioka, N. Kanda, S. Moriwaki, M. Musha, K. Nakazawa, K. Numata, S.-I. Sakai, N. Seto, T. Takashima, T. Tanaka, K. Agatsuma, K.-S. Aoyanagi, K. Arai, H. Asada, Y. Aso, T. Chiba, T. Ebisuzaki, Y. Ejiri, M. Enoki, Y. Eriguchi, M.-K. Fujimoto, R. Fujita, M. Fukushima, T. Futamase, K. Ganzu, T. Harada, T. Hashimoto, K. Hayama, W. Hikida, Y. Himemoto, H. Hirabayashi, T. Hiramatsu, F.-L. Hong, H. Horisawa, M. Hosokawa, K. Ichiki, T. Ikegami, K. TInoue, K. Ishidoshiro, H. Ishihara, T. Ishikawa, H. Ishizaki, H. Ito, Y. Itoh, N. Kawashima, F. Kawazoe, K. Naoko, K. Kiuchi, S. Kobayashi, K. Kohri, H. Koizumi, Y. Kojima, K. Kokeyama, W. Kokuyama, K. Kotake, Y. Kozai, H. Kudoh, H. Kunimori, H. Kuninaka, K. Kuroda, K.-I. Maeda, H. Matsuhara, Y. Mino, O. Miyakawa, S. Miyoki, M. YMorimoto, T. Morioka, T. Morisawa, S. Mukohyama, S. Nagano, I. Naito, K. Nakamura, H. Nakano, K. Nakao, S. Nakasuka, Y. Nakayama, E. Nishida, K. Nishiyama, A. Nishizawa, Y. Niwa, T. Noumi, Y. Obuchi, M. Ohashi, N. Ohishi, M. Ohkawa, N. Okada, K. Onozato, K. Oohara, N. Sago, M. Saijo, M. Sakagami, S. Sakata, M. Sasaki, T. Sato, M. Shibata, H. Shinkai, K. Somiya, H. Sotani, N. Sugiyama, Y. Suwa, R. Suzuki, H. Tagoshi, F. Takahashi, K. Takahashi, K. Takahashi, R. Takahashi, R. Takahashi, T. Takahashi, H. Takahashi, T. Akiteru, T. Takano, K. Taniguchi, A. Taruya, H. Tashiro, Y. Torii, M. Toyoshima, S. Tsujikawa, Y. Tsunesada, A. Ueda, K.-I. Ueda, M. Utashima, Y. Wakabayashi, H. Yamakawa, K. Yamamoto, T. Yamazaki, J. Yokoyama, C.-M. Yoo, S. Yoshida, T. Yoshino

    Journal of Physics: Conference Series　154　2009

    DOI： 10.1088/1742-6596/154/1/012040 　

    ISSN： 1742-6588

    eISSN： 1742-6596

  59. Gauge mediation with sequestered supersymmetry breaking Peer-reviewed

    Satoshi Shirai, Fuminobu Takahashi, T. T. Yanagida, Kazuya Yonekura

    Physical Review D - Particles, Fields, Gravitation and Cosmology　78　(7)　2008/10/06

    DOI： 10.1103/PhysRevD.78.075003 　

    ISSN： 1550-7998 1550-2368

  60. Inflaton decay in supergravity Peer-reviewed

    Motoi Endo, Fuminobu Takahashi, T. T. Yanagida

    Physical Review D - Particles, Fields, Gravitation and Cosmology　76　(8)　2007/10/12

    DOI： 10.1103/PhysRevD.76.083509 　

    ISSN： 1550-7998 1550-2368

  61. Retrofitted gravity mediation without the gravitino-overproduction problem Peer-reviewed

    Motoi Endo, Fuminobu Takahashi, T. T. Yanagida

    Physical Review D - Particles, Fields, Gravitation and Cosmology　76　(8)　2007/10/09

    DOI： 10.1103/PhysRevD.76.083508 　

    ISSN： 1550-7998 1550-2368

  62. Increasing the effective number of neutrinos with decaying particles Peer-reviewed

    Kazuhide Ichikawa, Masahiro Kawasaki, Kazunori Nakayama, Masato Senami, Fuminobu Takahashi

    AIP Conference Proceedings　957　413-416　2007

    DOI： 10.1063/1.2823816 　

    ISSN： 0094-243X 1551-7616

  63. Spontaneous nonthermal leptogenesis in high-scale inflation models Peer-reviewed

    Motoi Endo, Fuminobu Takahashi, T. T. Yanagida

    Physical Review D - Particles, Fields, Gravitation and Cosmology　74　(12)　2006

    DOI： 10.1103/PhysRevD.74.123523 　

    ISSN： 1550-7998 1550-2368

  64. Nonthermal production of dark matter from a late-decaying scalar field at an intermediate scale Peer-reviewed

    Motoi Endo, Fuminobu Takahashi

    Physical Review D - Particles, Fields, Gravitation and Cosmology　74　(6)　2006

    DOI： 10.1103/PhysRevD.74.063502 　

    ISSN： 1550-7998 1550-2368

  65. Gravitino-overproduction problem in an inflationary universe Peer-reviewed

    Masahiro Kawasaki, Fuminobu Takahashi, T. T. Yanagida

    Physical Review D - Particles, Fields, Gravitation and Cosmology　74　(4)　2006

    DOI： 10.1103/PhysRevD.74.043519 　

    ISSN： 1550-7998 1550-2368

  66. Moduli/inflaton mixing with supersymmetry-breaking field Peer-reviewed

    Motoi Endo, Koichi Hamaguchi, Fuminobu Takahashi

    Physical Review D - Particles, Fields, Gravitation and Cosmology　74　(2)　2006

    DOI： 10.1103/PhysRevD.74.023531 　

    ISSN： 1550-7998 1550-2368

  67. 511 keV line from Q balls in the galactic center Peer-reviewed

    S Kasuya, F Takahashi

    PHYSICAL REVIEW D　72　(8)　2005/10

    DOI： 10.1103/PhysRevD.72.085015 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  68. Oscillation effects on thermalization of the neutrinos in the universe with low reheating temperature Peer-reviewed

    K Ichikawa, M Kawasaki, F Takahashi

    PHYSICAL REVIEW D　72　(4)　2005/08

    DOI： 10.1103/PhysRevD.72.043522 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  69. Q-ball metamorphosis Peer-reviewed

    M Kawasaki, F Takahashi

    PHYSICAL REVIEW D　70　(4)　2004/08

    DOI： 10.1103/PhysRevD.70.043517 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  70. Spontaneous baryogenesis in flat directions Peer-reviewed

    F Takahashi, M Yamaguchi

    PHYSICAL REVIEW D　69　(8)　2004/04

    DOI： 10.1103/PhysRevD.69.083506 　

    ISSN： 0556-2821

  71. Curvatons in supersymmetric models Peer-reviewed

    K Hamaguchi, M Kawasaki, T Moroi, F Takahashi

    PHYSICAL REVIEW D　69　(6)　2004/03

    DOI： 10.1103/PhysRevD.69.063504 　

    ISSN： 2470-0010

    eISSN： 2470-0029

  72. [Formula Presented]-ball metamorphosis Peer-reviewed

    Masahiro Kawasaki, Fuminobu Takahashi

    Physical Review D - Particles, Fields, Gravitation and Cosmology　70　(4)　2004

    DOI： 10.1103/PhysRevD.70.043517 　

    ISSN： 1550-2368 1550-7998

  73. Moduli problem and baryogenesis in gauge-mediated SUSY breaking models Peer-reviewed

    S. Kasuya, M. Kawasaki, Fuminobu Takahashi

    Physical Review D - Particles, Fields, Gravitation and Cosmology　65　(6)　12　2002

    DOI： 10.1103/PhysRevD.65.063509 　

    ISSN： 1550-2368 1550-7998

  74. Large lepton asymmetry from [Formula Presented]-balls Peer-reviewed

    M. Kawasaki, Fuminobu Takahashi, Masahide Yamaguchi

    Physical Review D - Particles, Fields, Gravitation and Cosmology　66　(4)　8　2002

    DOI： 10.1103/PhysRevD.66.043516 　

    ISSN： 1550-2368 1550-7998

Show all ︎Show first 5

Misc. 5

  1. 19pSL-2 B-mode polarization as a probe of early universe and particle physics

    Takahashi Fuminobu

    Meeting abstracts of the Physical Society of Japan　69　(2)　42-42　2014/08/22

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  2. 17aSY-5 Discovery of non-thermal gravitino problem in inflaton decay

    Takahashi Fuminobu

    Meeting abstracts of the Physical Society of Japan　66　(2)　104-104　2011/08/24

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  3. 25aGR-2 Discovery of non-thermal gravitino problem in inflaton decay

    Takahashi Fuminobu

    Meeting abstracts of the Physical Society of Japan　66　(1)　101-101　2011/03/03

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  4. 23aSL-8 Gravititational Waves as a Probe of the Gravitino Mass

    Takahashi Fuminobu, Yanagida T.T., Yonekura Kazuya

    Meeting abstracts of the Physical Society of Japan　63　(2)　12-12　2008/08/25

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  5. 12aSF-9 Instability of the Q-ball in Affleck-Dine Baryogenesis

    Konya Kenichiro, Takahashi Fuminobu, Kawasaki Masahiro

    Meeting abstracts of the Physical Society of Japan　60　(2)　22-22　2005/08/19

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

Presentations 17

  1. Light Dark Matter Invited

    Fuminobu Takahashi

    “What is dark matter? - Comprehensive study of the huge discovery space in dark matter"　2025/04/25

  2. Fate of topological defects in multiple axion models

    Fuminobu Takahashi

    2024/10/22

  3. Bubble Misalignment Mechanism

    Fuminobu Takahashi

    DESY Theory Workshop　2024/09/26

  4. Inflation, the beginning of the universe Invited

    Fuminobu Takahashi

    2024/08/21

  5. Isotropic and anisotropic cosmic birefringence by axion domain walls Invited

    Fuminobu Takahashi

    1st iTHEMS Cosmology Forum, Riken　2024/05/14

  6. Light dark matter Invited

    Fuminobu Takahashi

    “What is dark matter? - Comprehensive study of the huge discovery space in dark matter"　2024/03/07

  7. Light Dark Matter

    Fuminobu Takahashi

    Extreme Mass Dark Matter Workshop from Superlight to Superheavy　2024/03/04

  8. Bubbles and Walls in Axion Cosmology Invited

    Fuminobu Takahashi

    2024 CAU-PNU Beyond the Standard Model Workshop　2024/02/19

  9. Trapped misalignment mechanism*, and its cosmological implications Invited

    Fuminobu Takahashi

    Advancements in Axion Physics 2023　2023/10/16

  10. Inflation, the beginning of the universe Invited

    KEK summer challenge　2023/08/19

  11. Axions in astrophysics and cosmology Invited

    Fuminobu Takahashi

    QUC school　2023/07/13

  12. Axion dark matter and its cosmological implications Invited

    Fuminobu Takahashi

    KPS-JPS symposium　2023/04/20

  13. Light Dark Matter Invited

    Fuminobu Takahashi

    “What is dark matter? - Comprehensive study of the huge discovery space in dark matter"　2023/03/07

  14. Dark Higgs EDE and axions Invited

    Fuminobu Takahashi

    Hubble Tension 2023@KEK　2023/02/22

  15. アクシオン宇宙論と最近の進展 Invited

    高橋 史宜

    第35回理論懇シンポジウム　2022/12/23

  16. Axion domain walls, and cosmic birefringence Invited

    高橋 史宜

    YU Workshop 2022 — Frontiers in Gravity and Fundamental Physics —　2022/11/27

  17. Light dark matter Invited

    Fuminobu Takahash

    i“What is dark matter;Comprehensive study of the huge discovery;space in dark matter”;Annual Symposium　2022/03/29

Show all Show first 5

Research Projects 22

  1. 広範な質量領域におけるアクシオンダイナミクスによる物質の起源の解明

    高橋 史宜

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 学術変革領域研究(A)

    Institution: 東北大学

    2025/04/01 - 2027/03/31

  2. What is dark matter? - Comprehensive study of the huge discovery space in dark matter

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Transformative Research Areas (A)

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

    Institution: The University of Tokyo

    2020/11/19 - 2025/03/31

  3. A theoretical study of the generation and evolution of light dark matter

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Transformative Research Areas (A)

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

    Institution: Tohoku University

    2020/11/19 - 2025/03/31

  4. 極弱相互作用を持つ軽い新粒子の描く新宇宙描像とその実験的検証

    高橋 史宜, 石渡 弘治, 北嶋 直弥

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(B)

    Institution: 東北大学

    2020/04/01 - 2025/03/31

    More details Close

    高橋は，現在の宇宙のバリオン非対称性を説明するひとつのシナリオとして知られていた，インフレーションが生じる前に非常に大きなバリオン非対称性を生成するシナリオに着目し，このようなシナリオにおいては断熱揺らぎと相関を持つバリオン等曲率揺らぎが大きくなりすぎることを発見した。これまでは原理的にはインフレーション以前に十分大きなバリオン数を用意すれば現在の宇宙に存在するバリオン非対称性を説明できると考えられていた。この結果，インフレーション以前にバリオン生成するシナリオは完全に棄却され，インフレーション後にバリオン非対称性を生成しなくてはならないことが初めて論理的に示すことができた。更にアクシオンの振動エネルギーがモノポールのWitten効果とシュウィンガー効果によって散逸することを指摘し，アクシオンダークマターに関するシナリオに示唆を与えた。石渡は宇宙観測と整合性の高い超共形ハイブリッドインフレーションモデルを拡張し、インフレーション後にレプトン数を生成する機構を考えた。保存量子数の伝搬の解析により、残存するバリオン数が現在の観測量と整合することを明らかにした。北嶋はHubble tensionに動機づけられたEarly dark energyのモデルとして極弱粒子であるアクシオンに着目し、自己共鳴現象による重力波生成を格子シミュレーションにより明らかにした。特に、宇宙背景放射の観測によりモデルの検証が可能であることを明らかにした。

  5. 極弱相互作用を持つ軽い新粒子の描く新宇宙描像とその実験的検証

    高橋 史宜, 石渡 弘治, 北嶋 直弥

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 基盤研究(B)

    Category: 基盤研究(B)

    Institution: 東北大学

    2020/04/01 - 2025/03/31

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    石渡は絶縁体中素励起としての準粒子アクシオンおよび初期宇宙におけるアクシオンに着目し、前者では磁性と準粒子アクシオンの関係を明瞭に定式化、後者ではアクシオンと非可換ゲージ場の相互作用から発生する原始重力波スペクトルを明らかにした。桜井はアクシオンと電弱スケールの新物理とのつながりを追求することを念頭に、ヒッグスセクターが拡張された模型において、荷電ヒッグスボソンの崩壊分岐比に対する輻射補正の効果を解析した。この研究により将来的に荷電ヒッグスボソンが発見された場合、崩壊分岐比を精密測定することで、拡張ヒッグス模型の識別が可能であることを明かにした。また、125GeVヒッグスボソンのインビジブル崩壊の量子補正を解析し、電弱スケールの新粒子による量子効果の影響が、現在のLHC実験の測定精度に匹敵し得ることを明らかにした。北嶋は，極弱粒子の代表例であるQCDアクシオンがダークマターとなるシナリオにおいて、背景時空および、背景輻射の断熱揺らぎの影響を考慮した解析を行い、QCDアクシオンの密度揺らぎの発展について非自明な効果を指摘した。高橋は宇宙複屈折を説明するシナリオとしてダークマターと結合した軽いアクシオンの運動を提唱した。これによって、宇宙複屈折の時期が自然にmatter-radiation equalityの時期に近いことが説明することができた。またQCDアクシオンの運動がPeccei-Quinn対称性の破れが存在する場合にどのように変化する場合を解析的および数値的に明らかにした。特に、崩壊定数が非常に小さい場合であっても、適当な破れを導入することによって、等曲率ゆらぎを抑えつつダークマターを説明することができるということを明らかにした。

  6. Experimental tests of high-scale supersymmetry

    Yanagida Tsutomu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: The University of Tokyo

    2017/04/01 - 2022/03/31

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    We have comprehensively studied the high-scale SUSY model from the viewpoint of collider and indirect dark matter detections, as well as theoretical developments for the extension of the model. As for the collider detection, we have developed the wino and higgsino dark matter studies using the disappearing charged-track and the radiative correction to SM lepton pair productions, and those of the gluino using a machine-learning technic to suppress the background. As for the indirect detection, we have proposed a new algorithm for accurately estimating the dark matter distribution at dwarf spheroidal galaxies and contributed to the control of the background against the signal. As for theoretical studies, we have proposed the possibility of having other dark matter candidates in the model and the extension of the model to explain the “anomaly” of the muon anomalous magnetic moment.

  7. Cosmological Evolution and Search for Light New Particles with Ultraweak Interactions

    Takahashi Fuminobu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2017/04/01 - 2021/03/31

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    We have proposed new cosmological evolution and production process of the weakly interacting slim particles. As a representative result, we proposed a new production mechanism by axions in the scenario where dark photons become dark matter. In particular, it was found that dark photons with extremely low masses, which were difficult to produce, can become cold dark matter. We also find that the cosmological upper bound on the axion decay constant is relaxed significantly by considering the stochastic dynamics of the QCD axion during inflation.

  8. Why does the Universe accelerate? - Exhaustive study and challenge for the future -

    MURAYAMA HITOSHI

    Offer Organization: Japan Society for the Promotion of Science

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

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

    Institution: The University of Tokyo

    2015/11/06 - 2020/03/31

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    The purpose of this innovative research area is to reveal the physics driving accelerating expansion of the universe that should have occurred at the beginning and is now happening today. With the aid of support from this grant supporting international collaboration, we made the following, main achievements. We were able to efficiently and surely make progress in international collaborations, especially instrumentation, experiment and observational projects under this research program. Junior researchers of our group managed to establish an international collaboration between totally independent projects, the CMB experiment POLARBEAR and the Subaru Hyper Suprime-Cam (HSC) project. The international team made a detection of the gravitational lensing due to cosmic structures from the two independent datasets, for the first time (Chinone et al. 2019). The Subaru HSC international collaboration made accurate measurements of cosmological parameters.

  9. Exploring the evolution of the fluctuations and structure of the Universe, and the physics behind it

    Takahashi Fuminobu

    Offer Organization: Japan Society for the Promotion of Science

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

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

    Institution: Tohoku University

    2015/06/29 - 2020/03/31

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    Dark matter played a central role in shaping the structure of the universe, but its identity is shrouded in mystery. In this study, we present the possibility of primordial black holes as a part of dark matter and their formation process, the elaboration of cosmological restrictions on the pair annihilation and decay of dark matter, the new formation process of axions and light dark photon dark matter, a detailed comparison between the Lagrangian perturbation theory and Vlasov-Poisson simulations of the phenomenon called shell crossing during halo formation, the construction of a unified model of inflation and dark matter, and the derivation of restrictions on the isocurvature fluctuations of dark matter and dark energy based on the Swampland conjecture.

  10. Quest for the Ultimate Theory in terms of rich cosmophysical phenomena caused by fields and particles in the hidden sector

    Kodama Hideo, KOBAYASHI Tatsuo, SODA Jiro, MIZOGUCHI Shun'ya, SUMITOMO Yoske, NOZAWA Masato

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

    Category: Grant-in-Aid for Scientific Research (A)

    2014/06/27 - 2018/03/31

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    We have systematically explored methods to probe whether the unified theory called string theory is the ultimate theory of Nature in terms of observations of phenomena caused by fields and particle in the hidden sector specific to superstring theory. As a result, we have proposed lots of new methods such as the observation of gravitational waves produced by the interaction between black holes and a scalar field called axion, observations of gamma rays from high-energy astrophysical objects and cosmic infrared background radiations, observations of electromagnetic and gravitational waves passing through axion dark matter, new particle searches by accelerator experiments, CMB observations of inflation in the early universe. Further, we have constructed some concrete examples of superstring compactifications that are consistent with both the standard model of elementary particles and cosmology.

  11. Theoretical and phenomenological studies of High-scale supersymmetric model

    Yanagida Tsutomu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: The University of Tokyo

    2014/04/01 - 2017/03/31

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    We have intensively studied the high-scale supersymmetry model (Pure gravity mediation model) form both theoretical and phenomenological viewpoints, which is now known to be one of the most influential models thanks to the discovery of the Higgs boson at the LHC as well as the non-observation of robust new physics signals at various experiments and observations. We have proposed a novel idea to solve the so-called the hierarchy problem concerning the electroweak scale within the framework of the modal and have shown that the indirect detection of the dark matter (predicted in the model) utilizing the gamma-ray observation of dwarf spheroidal galaxies allows us to robustly test the model in near future.

  12. Evolution of the early Universe based on the results of Planck and LHC

    Takahashi Fuminobu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)

    Category: Grant-in-Aid for Young Scientists (B)

    Institution: Tohoku University

    2012/04/01 - 2016/03/31

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    During the period of this grant, a standard-model like Higgs boson was discovered at the LHC, and various cosmological parameters were pinned down by the Planck results on the cosmic microwave background radiation anisotropies. However, so far, there is no hint for any physics beyond the standard model, primordial non-Gaussianity of density perturbations, primordial gravitational waves, dark radiation, the running of the scalar spectral index, and so on. Based on these experimental and observational results, I wrote 65 papers on various topics about the early Universe ranging from inflation model building based on the Higgs boson, right-handed sneutrinos, etc., evolution of the QCD axion and its isocurvature fluctuations, to production of axionic dark radiation by the modulus decay. I gave talks at various domestic and international conferences, including many plenary talks. I also gave series of intense lectures on inflation, lectures at summer and winter schools.

  13. Early Universe in the Era of LHC

    Yamaguchi Masahiro, MOROI Takeo, TAKAHASHI Fuminobu

    Offer Organization: Japan Society for the Promotion of Science

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

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

    Institution: Tohoku University

    2011/04/01 - 2016/03/31

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    The discovery of the Higgs particle with 125 GeV mass at the LHC experiment has a great impact on the establishment of the standard model of particle physics, the directions beyond the standard model, and cosmology based on it. We have investigated, in the light of the discovery of the Higgs particle, the influences on the model buildings of supersymmetric standard models, the inflation models driven by the Higgs boson, the dark radiaton of the Universe in the Higgs portal models, and the cosmological implications of the supersymmetric Peccei-Quinn models and so on.

  14. Helicity amplitudes for general spin and physics beyond the standard model at LHC

    HIKASA Ken-ichi, TAKAHASHI Fuminobu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)

    Category: Grant-in-Aid for Scientific Research (C)

    Institution: Tohoku University

    2012/04/01 - 2015/03/31

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    Helicity amplitudes are useful for processes in high energy physics, especially when parity-violating interactions are involved. We have developed a formalism to evaluate helicity amplitudes of processes including particles with spin higher than one in terms of Wigner's d functions. We examine new physics processes at the LHC collider in models including several scenarios in the supersymmetric standard model. Limits on the scalar top quark mass is derived using ATLAS data from LHC in the natural SUSY scenario. We also study models with pseudo-goldstinos and find that future high-luminosity LHC will be able to detect production of neutralinos/charginos decaying to pseudo-goldstinos emitting W, Z, or Higgs bosons.

  15. research on cosmological nonlinear and non-perturbative gravitational phenomena

    SASAKI Misao, TANAKA Takahiro, SHIROMIZU Tetsuya, SODA Jiro, MUKOHYAMA Shinji, MATSUBARA Takahiko, TAKAHASHI Fuminobu, CHIBA Takeshi, TSUJIKAWA Shinji, ISHIHARA Hideki, YAMAMOTO Kazuhiro, YAMAGUCHI Masahide

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: Kyoto University

    2009/04/01 - 2015/03/31

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    It is believed that the universe has undergone a stage of accelerated expansion, an inflationary stage, right after the birth, and all the fluctuations that are responsible for the structure of the universe today were generated during this stage. One of the most important issues in cosmology is to understand how these fluctuations have evolved to the large scale structure of the universe such as galaxies through nonlinear and non-perturbative gravitational phenomena. In this project, we have systematically investigated various types of fluctuations, from microscopic quantum fluctuations to macroscopic fluctuations of spacetime, and obtained many world top-class results. These results form an important basis for the future direction of research in cosmology.

  16. 非ガウス性から探る密度揺らぎの起源と進化

    高橋 史宜

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 新学術領域研究(研究領域提案型)

    Category: 新学術領域研究(研究領域提案型)

    Institution: 東北大学

    2012/04/01 - 2014/03/31

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    Planckの観測発表を受け、密度揺らぎの非ガウス性に対する制限は非常に厳しいものとなった。そこで、カーバトンなどのspectator field模型が満たすべき条件を観測結果発表直後に調べあげ論文として発表した。更に、QCDアクシオンがつくる等曲率ゆらぎとその非ガウス性を解析的及び数値的に求め、この厳しい制限を用いてアクシオンとインフレーションスケールに制限を導くことができた。また等曲率揺らぎの制限を避けるために、QCDアクシオンがインフレーション中に非常に重くなる理論的可能性を追求した。一方、Planck衛星の観測結果を受け、Polynomical chaotic inflationを４次元超重力理論の枠組みで構築した。更に、ごく最近発表のあったBICEP2の結果を説明するHiggs chaotic inflationおよびmulti-natural inflation模型を提唱した。特に、後者においては、通常作るのが非常に困難である大きなrunning spectral indexが生成可能であることを具体的に示し、Planckとのtensionを解く可能性を論じた。このように、現在の宇宙の揺らぎの起源を探ることを第一の目的として研究を進めてきた結果、新しい観測結果と合わせ、その起源の可能性をかなり絞り込むことができた。更に、暗黒物質の有力な候補であるQCDアクシオンに対する制限が非常に厳しいということも、BICEP2の発表後、世界に先駆けて発表することができた。従って、この研究において、学術的な成果を確実にあげ、かつ熾烈な研究競争に勝ったといえる。

  17. The exploration of extradimensions in terms of a variety of cosmophysical phenomena caused by axionic moduli

    KODAMA Hideo, OHTA Nobuyoshi, TAKAHASHI Fuminobu, NAKAYAMA Kazunori, OHTA Nobuyoshi, SHIBATA Masaru, MIZOGUCHI Shun'ya, KOBAYASHI Tatsuo, SODA Jiro, KOHRI Kazunori, ISHIBASHI Akihiro, IOKA Kuninito, TAKAHASHI Fuminobu, YOSHINO Hirotaka, NOZZWA Masato, NAGATA Ryo, KAWANAKA Norita, TOMIZAWA Shin'ya

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: High Energy Accelerator Research Organization

    2010/04/01 - 2014/03/31

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    In order to open up a new observational/experimental window to the ultimate theory, we have studied axions from both the cosmophysics phenomenology aspect and the superstring/supergravity aspect and have published more than 200 papers. The main achievements are demonstarations of the axion bose nova phenemenon caused by a rotating black hole by numerical simulations and the discovery of its observability by gravitational wave experiments, derivation of a parameter range for axion to resolve the conflict between the high energy gamma-ray observations and the infrared background observation, evaluations of the influences of axions produced by the decay of heavy moduli on cosmic microwave background and derivation of constraints on the compactification of extra-dimensions on the basis of this estimation, derivation of constraints on elementary particle models from cosmological influences of axionic isocurvature perturbations and topological defects.

  18. Quest for the ultimate theory on the basis of direct observations of the early evolution of the universe

    KODAMA Hideo, KAWASAKI Masahiro, YOKOYAMA Jun'ichi, SODA Jiro, TSUJIKAWA Shinji, MUKOHYAMA Shinji, NAKAYAMA Kazunori, KITAZAWA Yoshihisa, CHIBA Takeshi, SHIROMIZU Tetsuya, TANAKA Takahiro, KOHRI Kazunori, TAKAHASHI Fuminobu, NOZZWA Masato, NAKAYAMA Kazunori

    Offer Organization: Japan Society for the Promotion of Science

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

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

    Institution: High Energy Accelerator Research Organization

    2009/07/23 - 2014/03/31

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    In this project, we have pushed forward investigations from the two different directions, the phenomomenology of the universe focused on cosmological fluctuations and the construction of universe models based on unified theories including gravity, and published more than 300 papers. The most significant resutls are the construction of the most general inflation theory with a single driving scalar field and the comparison of its predictions with observations, the construction of a consistent anisotropic inflation model and the derivation of its detailed observational predictions, the construction of a variety of large field inflation models on the basis of 4D supergravity unified theories, derivation of constraints on elementary particle theory on the basis of investigations of axion cosmology by 3D numerical simulations, clarification of the IR divergence problem in quantum correstions to inflation, and systematic studies of various modified gravity theories.

  19. 低エネルギーインフレーション模型における整合的宇宙論の構築とその観測的検証

    高橋 史宜

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 新学術領域研究(研究領域提案型)

    Category: 新学術領域研究(研究領域提案型)

    2010 - 2011

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    インフレーションはビッグバン標準宇理論に内在する平坦性問題、地平線問題、モノポール問題などを一挙に解決し、さらに、現在観測される銀河や銀河団などの構造形成の種となる密度揺らぎをつくりだすことができる。特に最近の精密な宇宙背景輻射の温度揺らぎの観測から強く示唆されている。インフレーション模型は多岐にわたり、実隙にどのようなインフレーションが実現したのかは分かっていない。その中で、低エネルギーインフレーションはストリング理論におけるモヂュライの安定化やグラビティーノ問題の観点から有力な候補である。低エネルギーインフレーションの初期値問題を系統的に調べるという研究計画に基づき、研究をすすめた結果、初期値問題を自然に解決する為には、プラズマと熱的相互作用をし、原点において対称性が回復するnew inflation模型が魅力的であるという結論に至った。そこで80年代の研究動向を探った結果、超対称性の破れとインフレーションスケールに関して重要な関係が看過されている事に気がついた。具体的には、ゲージ相互作用を持つインフラトンがインフレーションを引き起こすためには、超対称性がインフレーションスケールよりも下に無ければならない、という事を初めて示した。更に、ニュートリノ振動実験とシーソー機構からその存在が示唆されているB-Lゲージ対称性に基づく低エネルギースケールインフレーション模型を構築し、超対称性がおよそPeVスケール以下に無ければならない事、それが現在LHC実験で示唆されている標準模型ヒッグス粒子質量と無矛盾であること、さらに、非熱的レプトジェネシス機構が自然に働く事で観測されているバリオン非対称性を説明できることを示した。これは宇宙初期進化と高エネルギー実験を結びつける非常に重要な成果となった。

  20. Research on inflationary universe and density perturbation based on

    TAKAHASHI Fuminobu

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)

    Category: Grant-in-Aid for Young Scientists (B)

    2009 - 2011

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    The ATLAS and CMS collaborations at the LHC experiment reported hints of a standard model Higgs boson at about 125GeV, which can be naturally explained in a supersymmetric framework with supersymmetry breaking at 100-1000TeV. I studied its cosmological implications and proposed an inflation model based on U(1)B-L gauge symmetry. In this model the inflationary scale places an upper limit on the supersymmery breaking which explains the Higgs mass naturally.

  21. インフレーション宇宙における密度揺らぎの進化と物質及び暗黒物質の起源

    高橋 史宜

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 特別研究員奨励費

    Category: 特別研究員奨励費

    Institution: 東京大学

    2005 - 2007

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    本年度は、まずモヂュライからのグラビティーノ生成が、従来考えられていたよりもずっと大きなレートで起こる事を示した。これまではモヂュライ質量を100TeV以上にすればビッグバン元素合成前に崩壊し、問題がないと考えられてきた。しかしながら、我々の発見により、モヂュライ質量を重くするだけでは一般にモヂュライ問題は解けないことが明らかになった。この発見は非常に重要で、モヂュライのstabilization機構に対して強い制限を課す。更に、インフラトンからもグラビティーノを作られる事を示した。この発見によって超重力理論における多くのインフレーションモデルを制限することに成功した。特に、ハイブリッドインフレーション、スムーズハイブリッドインフレーションモデルなどの高エネルギーインフレションモデルに対して激しい制限を課した。また、同時に超対称性の破れを伝える機構に制限を課す。特に、グラビティーメディエイションはほぼ排除された。更に、インフラトンが一般的に超重力効果によってビジブルセクターに崩壊することを発見した。これによりインフラトンによる再加熱が相互作用を手で入れなくても自然に起こることが分かった。従来、再加熱はインフラトンセクターとビジブルセクターの間の相互作用を手で入れて起こすしかないと考えられていたために、フリーパラメターとして扱われてきた。しかしながら、超重力効果による相互作用を通じた再加熱プロセスの発見により、フリーパラメターはなく、インフレーションモデルを決めれば再加熱温度の下限が決まることが分かった。

  22. インフレーション宇宙における物質の起源とその揺らぎの進化

    高橋 史宜

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 特別研究員奨励費

    Category: 特別研究員奨励費

    Institution: 東京大学

    2003 - 2004

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    WMAPの観測結果はインフレーションモデルに様々な示唆を与えた。特に大きなスケールにおいて揺らぎが極端に小さい可能性がある事が指摘された。我々は超対称性理論に基づいたインフレーションモデルによってこの様な特徴を持った宇宙背景輻射を生成することが可能である事を示したが、現実的なインフレーションモデルを用いて示したのは我々が最初である。加えて、WMAPの結果はCMBの角度スペクトラムに音波振動によるピークとは異なる振動パターンが存在する可能性を示唆している。我々はインフレーションがつくる初期密度揺らぎに鋭いピークあるいは凹みがあれば、この様な振動パターンが生成されることを示した。更に我々は、従来困難と思われていた、超対称性標準理論の枠組み内でのインフレーションモデルの構築に成功した。このモデルは未発見の超対称性粒子の質量行列にある種の予言をするため、宇宙背景輻射の観測だけではなく近い将来LHCなどのコライダー実験によって検証可能である。 モヂュライと呼ばれる重力的にしか相互作用しないスカラー場の存在が超ひも理論等で予言されている。しかしながら、この様なスカラー場は様々な宇宙論的問題を引き起こす。この問題を解決する為、thermal inflationに代表される様に、大きなエントロピー生成によってモヂュライを薄めるアイデアがあった。しかしながら、thermal inflationはアフレックダインバリオン生成機構と両立しないという問題がある。そこで我々は位相欠陥を用いた新しいエントロピー生成を提案し、モヂュライ問題を解決しつつ、バリオン生成機構と両立しうる事を示した。

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Teaching Experience 1

  1. Particle Physics　Tohoku University

Social Activities 2

  1. 宇宙の始まりと終わり

    2023/09/30 -

  2. 宇宙の始まりと終わり

    2022/08/19 -