Research activity information

• Sep. 2026 The Physical Society of Japan, 4th AAPPS-JPS, Theoretical Studies on Cosmological First-order Phase Transitions


• Sep. 2021 Japan Particle and Nuclear Theory Forum, Particle Physics Medal: Young Scientist Award in Theoretical Particle Physics

  Ryusuke Jinno

• Axion-photon conversion in stochastic magnetic fields

  Chiba, Wataru, Jinno, Ryusuke, Nomura, Kimihiro

  Jun. 2026, Phys.Rev.D, 113(11) (11), 115037 - 115037

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Curvature Perturbations from First-Order Phase Transitions: Implications to Black Holes and Gravitational Waves

  Franciolini, Gabriele, Gouttenoire, Yann, Jinno, Ryusuke

  Apr. 2026, Phys.Rev.Lett., 136(17) (17), 171404 - 171404

  Scientific journal


• Gravitational Waves from Feebly Interacting Particles in a First Order Phase Transition

  Ryusuke Jinno, Bibhushan Shakya, Jorinde van de Vis

  Mar. 2026, Physical Review Letters

  Scientific journal


• Cancellation of one-loop correction to soft tensor power spectrum

  Yohei Ema, Muzi Hong, Ryusuke Jinno, Kyohei Mukaida

  Jan. 2026, Journal of Cosmology and Astroparticle Physics

  Scientific journal


• Graviton-photon conversion in stochastic magnetic fields

  Chiba, Wataru, Jinno, Ryusuke, Nomura, Kimihiro

  Oct. 2025, Phys.Rev.D, 112(8) (8), 083539 - 083539

  Scientific journal


• Gravitational waves from first-order phase transitions: from weak to strong

  Chiara Caprini, Ryusuke Jinno, Thomas Konstandin, Alberto Roper Pol, Henrique Rubira, Isak Stomberg

  Jul. 2025, Journal of High Energy Physics

  Scientific journal


• Leptogenesis in the presence of density perturbations

  Kenta Hotokezaka, Ryusuke Jinno, Rin Takada

  Jun. 2025, Physical Review D

  Scientific journal


• Acoustically driven dark matter freeze-out

  Baldes, Iason, Jinno, Ryusuke

  Jun. 2025

  Scientific journal


• Gravitational effects on fluid dynamics in cosmological first-order phase transitions

  Ryusuke Jinno, Jun'ya Kume

  Feb. 2025, Journal of Cosmology and Astroparticle Physics

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Exactly solvable stochastic spectator

  Masazumi Honda, Ryusuke Jinno, Koki Tokeshi

  Dec. 2024, Journal of Cosmology and Astroparticle Physics

  Scientific journal


• Finite Bubble Statistics Constrain Late Cosmological Phase Transitions

  Elor, Gilly, Jinno, Ryusuke, Kumar, Soubhik, McGehee, Robert, Tsai, Yuhsin

  Nov. 2024, Phys.Rev.Lett., 133(21) (21), 211003 - 211003

  Scientific journal


• Gravitational waves from first-order phase transitions in LISA: reconstruction pipeline and physics interpretation

  Chiara Caprini, Ryusuke Jinno, Marek Lewicki, Eric Madge, Marco Merchand, Germano Nardini, Mauro Pieroni, Alberto Roper Pol, Ville Vaskonen

  Oct. 2024, Journal of Cosmology and Astroparticle Physics

  Scientific journal


• Neutrino zeromodes on electroweak strings in light of topological insulators

  Minoru Eto, Yu Hamada, Ryusuke Jinno, Muneto Nitta, Masatoshi Yamada

  Jun. 2024, Journal of High Energy Physics

  Scientific journal


• Testing multi-field inflation with LiteBIRD

  Jinno, Ryusuke, Kazunori Kohri, Moroi, Takeo, Tomo Takahashi, Hazumi, Masashi

  Mar. 2024, JCAP, 03, 011 - 011

  Scientific journal


• Super-slow phase transition catalyzed by BHs and the birth of baby BHs

  Ryusuke Jinno, Jun'ya Kume, Masaki Yamada

  Feb. 2024, Physics Letters B

  Scientific journal


• Super-slow phase transition catalyzed by BHs and the birth of baby BHs

  Jinno, Ryusuke, Kume, Jun'ya, Yamada, Masaki

  Jan. 2024, Phys.Lett.B, 849, 138465 - 138465

  Scientific journal


• Quartic Gradient Flow

  Hong, Muzi, Jinno, Ryusuke

  Jan. 2024, Phys.Lett.B, 849, 138441 - 138441

  Scientific journal


• Gravitational waves from defect-driven phase transitions: domain walls

  Blasi, Simone, Jinno, Ryusuke, Konstandin, Thomas, Rubira, Henrique, Stomberg, Isak

  Oct. 2023, JCAP, 10, 051 - 051

  Scientific journal


• Cosmology with the Laser Interferometer Space Antenna

  Auclair, Pierre, Bacon, David, Baker, Tessa, Barreiro, Tiago, Bartolo, Nicola, Belgacem, Enis, Bellomo, Nicola, Ben-Dayan, Ido, Bertacca, Daniele, Besancon, Marc, Blanco-Pillado, Jose J., Blas, Diego, Boileau, Guillaume, Calcagni, Gianluca, Caldwell, Robert, Caprini, Chiara, Carbone, Carmelita, Chang, Chia-Feng, Chen, Hsin-Yu, Christensen, Nelson, Clesse, Sebastien, Comelli, Denis, Congedo, Giuseppe, Contaldi, Carlo, Crisostomi, Marco, Croon, Djuna, Cui, Yanou, Cusin, Giulia, Cutting, Daniel, Dalang, Charles, De Luca, Valerio, Del Pozzo, Walter, Desjacques, Vincent, Dimastrogiovanni, Emanuela, Dorsch, Glauber C., Ezquiaga, Jose Maria, Fasiello, Matteo, Figueroa, Daniel G., Flauger, Raphael, Franciolini, Gabriele, Frusciante, Noemi, Fumagalli, Jacopo, García-Bellido, Juan, Gould, Oliver, Holz, Daniel, Iacconi, Laura, Jain, Rajeev Kumar, Jenkins, Alexander C., Jinno, Ryusuke, Joana, Cristian, Karnesis, Nikolaos, Konstandin, Thomas, Koyama, Kazuya, Kozaczuk, Jonathan, Kuroyanagi, Sachiko, Laghi, Danny, Lewicki, Marek, Lombriser, Lucas, Madge, Eric, Maggiore, Michele, Malhotra, Ameek, Mancarella, Michele, Mandic, Vuk, Mangiagli, Alberto, Matarrese, Sabino, Mazumdar, Anupam, Mukherjee, Suvodip, Musco, Ilia, Germano Nardini, No, Jose Miguel, Papanikolaou, Theodoros, Peloso, Marco, Pieroni, Mauro, Pilo, Luigi, Raccanelli, Alvise, Renaux-Petel, Sébastien, Renzini, Arianna I., Ricciardone, Angelo, Riotto, Antonio, Romano, Joseph D., Rollo, Rocco, Pol, Alberto Roper, Morales, Ester Ruiz, Sakellariadou, Mairi, Saltas, Ippocratis D., Scalisi, Marco, Schmitz, Kai, Schwaller, Pedro, Sergijenko, Olga, Servant, Geraldine, Simakachorn, Peera, Sorbo, Lorenzo, Sousa, Lara, Speri, Lorenzo, Steer, Danièle A., Tamanini, Nicola, Tasinato, Gianmassimo, Torrado, Jesús, Unal, Caner, Vennin, Vincent, Vernieri, Daniele, Vernizzi, Filippo, Volonteri, Marta, Wachter, Jeremy M., Wands, David, Witkowski, Lukas T., Zumalacárregui, Miguel, Annis, James, Ares, Fëanor Reuben, Avelino, Pedro P., Avgoustidis, Anastasios, Barausse, Enrico, Bonilla, Alexander, Bonvin, Camille, Bosso, Pasquale, Calabrese, Matteo, Çalışkan, Mesut, Cembranos, Jose A.R., Chala, Mikael, Chernoff, David, Clough, Katy, Criswell, Alexander, Das, Saurya, da Silva, Antonio, Dayal, Pratika, Domcke, Valerie, Durrer, Ruth, Easther, Richard, Escoffier, Stephanie, Ferrans, Sandrine, Fryer, Chris, Gair, Jonathan, Gordon, Chris, Hendry, Martin, Hindmarsh, Mark, Hooper, Deanna C., Kajfasz, Eric, Kopp, Joachim, Koushiappas, Savvas M., Kumar, Utkarsh, Kunz, Martin, Lagos, Macarena, Lilley, Marc, Lizarraga, Joanes, Lobo, Francisco S.N., Maleknejad, Azadeh, Martins, C.J. A.P., Meerburg, P. Daniel, Meyer, Renate, Mimoso, José Pedro, Nesseris, Savvas, Nunes, Nelson, Oikonomou, Vasilis, Orlando, Giorgio, Özsoy, Ogan, Pacucci, Fabio, Palmese, Antonella, Petiteau, Antoine, Pinol, Lucas, Portegies Zwart, Simon, Pratten, Geraint, Prokopec, Tomislav, Quenby, John, Rastgoo, Saeed, Roest, Diederik, Rummukainen, Kari, Schimd, Carlo, Secroun, Aurélia, Sesana, Alberto, Sopuerta, Carlos F., Tereno, Ismael, Tolley, Andrew, Urrestilla, Jon, Vagenas, Elias C., van de Vis, Jorinde, van de Weygaert, Rien, Wardell, Barry, Weir, David J., White, Graham, Świeżewska, Bogumiła, Zhdanov, Valery I.

  Aug. 2023, Living Rev.Rel., 26(1) (1), 5 - 5

  Scientific journal


• Borel resummation of secular divergences in stochastic inflation

  Honda, Masazumi, Jinno, Ryusuke, Pinol, Lucas, Koki Tokeshi

  Aug. 2023, JHEP, 08, 060 - 060

  Scientific journal


• Machine learning Post-Minkowskian integrals

  Ryusuke Jinno, Gregor Kälin, Zhengwen Liu, Henrique Rubira

  Jul. 2023, Journal of High Energy Physics, 07, 181 - 181

  Scientific journal


• Tunneling potential actions from canonical transformations

  Espinosa, José R., Jinno, Ryusuke, Konstandin, Thomas

  Feb. 2023, JCAP, 02, 021 - 021

  Scientific journal


• Higgsless simulations of cosmological phase transitions and gravitational waves

  Jinno, Ryusuke, Konstandin, Thomas, Rubira, Henrique, Stomberg, Isak

  Feb. 2023, JCAP, 02, 011 - 011

  Scientific journal


• Abrikosov-Nielsen-Olesen strings from the Coleman-Weinberg potential

  MINORU ETO, Yu Hamada, Ryusuke Jinno, Muneto Nitta, Masatoshi Yamada

  Dec. 2022, Phys.Rev.D, 106(11) (11), 116002 - 116002

  Scientific journal


• Detection of early-universe gravitational-wave signatures and fundamental physics

  Caldwell, Robert, Cui, Yanou, Huaike Guo, Mandic, Vuk, Mariotti, Alberto, No, Jose Miguel, Ramsey-Musolf, Michael J., Sakellariadou, Mairi, Sinha, Kuver, Wang, Lian-Tao, White, Graham, Zhao, Yue, An, Haipeng, Bian, Ligong, Caprini, Chiara, Clesse, Sebastien, Cline, James M., Cusin, Giulia, Jinno, Ryusuke, Laurent, Benoit, Noam Levi, Lyu, Kunfeng, Lyu, Kun-Feng, MARIO MARTINEZ, Andrew L. Miller, diego redigolo, Claudia Scarlata, Alexander Sevrin, Barmak Shams Es Haghi, Jing Shu, Siemens, Xavier, Danièle STEER, Sundrum, Raman, Carlos Tamarit, David James Weir, Fornal, Bartosz, Ke-Pan Xie, Yang, Fengwei, Fengwei Yang, Zhou, Siyi

  Nov. 2022, Gen.Rel.Grav., 54(12) (12), 156 - 156

  Scientific journal


• Gravitational Waves from Feebly Interacting Particles in a First Order Phase Transition

  Jinno, Ryusuke, Shakya, Bibhushan, van de Vis, Jorinde

  Nov. 2022

  Scientific journal


• Friction pressure on relativistic bubble walls

  Yann Gouttenoire, Ryusuke Jinno, Filippo Sala

  May 2022, Journal of High Energy Physics, 05, 004 - 004

  Scientific journal


• Effect of density fluctuations on gravitational wave production in first-order phase transitions

  Jinno, Ryusuke, Konstandin, Thomas, Rubira, Henrique, van de Vis, Jorinde

  Dec. 2021, JCAP, 12(12) (12), 019 - 019

  Scientific journal


• Negative mode problem of false vacuum decay revisited

  Ryusuke Jinno, Ryosuke Sato

  Nov. 2021, Physical Review D, 104(9) (9), 096009 - 096009

  Scientific journal


• Probing PeV scale SUSY breaking with satellite galaxies and primordial gravitational waves

  Choi, Gongjun, Jinno, Ryusuke, Yanagida, Tsutomu T.

  Nov. 2021, Phys.Rev.D, 104(9) (9), 095018 - 095018

  Scientific journal


• Preheating from target space curvature and unitarity violation: Analysis in field space

  Ema, Yohei, Jinno, Ryusuke, Nakayama, Kazunori, van de Vis, Jorinde

  May 2021, Phys.Rev.D, 103(10) (10), 103536 - 103536

  Scientific journal


• A hybrid simulation of gravitational wave production in first-order phase transitions

  Jinno, Ryusuke, Konstandin, Thomas, Rubira, Henrique

  Apr. 2021, JCAP, 04, 014 - 014

  Scientific journal


• Occurrence of tachyonic preheating in the mixed Higgs-R$^2$ model

  He, Minxi, Ryusuke Jinno, Kamada, Kohei, Starobinsky, Alexei A., Yokoyama, Jun'ichi

  Jan. 2021, JCAP, 01, 066 - 066

  Scientific journal


• High-frequency Graviton from Inflaton Oscillation

  Yohei Ema, Ryusuke Jinno, Nakayama, Kazunori

  Sep. 2020, JCAP, 09, 015 - 015

  Scientific journal


• Deformation of the gravitational wave spectrum by density perturbations

  Domcke, Valerie, Jinno, Ryusuke, Rubira, Henrique

  Jun. 2020, JCAP, 06, 046 - 046

  Scientific journal


• Higgs inflation in metric and Palatini formalisms: Required suppression of higher dimensional operators

  Jinno, Ryusuke, Kubota, Mio, Oda, Kin-ya, Park, Seong Chan

  Mar. 2020, JCAP, 03, 063 - 063

  Scientific journal


• Fingerprint matching of beyond-WIMP dark matter: neural network approach

  Bae, Kyu Jung, Jinno, Ryusuke, Kamada, Ayuki, Yanagi, Keisuke

  Mar. 2020, JCAP, 03, 042 - 042

  Scientific journal


• Gravitational waves from first-order phase transitions: Ultra-supercooled transitions and the fate of relativistic shocks

  Jinno, Ryusuke, Seong, Hyeonseok, Takimoto, Masahiro, Um, Choong Min

  Oct. 2019, JCAP, 10, 033 - 033

  Scientific journal


• Relativistic bubble collisions—a closer look

  Jinno, Ryusuke, Konstandin, Thomas, Takimoto, Masahiro

  Sep. 2019, JCAP, 09, 035 - 035

  Scientific journal


• Selecting models of first-order phase transitions using the synergy between collider and gravitational-wave experiments

  Hashino, Katsuya, Jinno, Ryusuke, Kakizaki, Mitsuru, Kanemura, Shinya, Takahashi, Tomo, Takimoto, Masahiro

  Apr. 2019, Phys.Rev.D, 99(7) (7), 075011 - 075011

  Scientific journal


• Hillclimbing inflation in metric and Palatini formulations

  Jinno, Ryusuke, Kaneta, Kunio, Oda, Kin-ya, seongchan park

  Apr. 2019, Phys.Lett.B, 791, 396 - 402

  Scientific journal


• On the violent preheating in the mixed Higgs-$R^2$ inflationary model

  Minxi He, Jinno, Ryusuke, Kamada, Kohei, seongchan park, Starobinsky, Alexei A., Yokoyama, Jun'ichi

  Apr. 2019, Phys.Lett.B, 791, 36 - 42

  Scientific journal


• Gravitational waves from bubble dynamics: Beyond the Envelope

  Jinno, Ryusuke, Takimoto, Masahiro

  Jan. 2019, JCAP, 01, 060 - 060

  Scientific journal


• Machine learning for bounce calculation

  Jinno, Ryusuke

  May 2018

  Scientific journal


• Hill-climbing Higgs inflation

  Jinno, Ryusuke, Kaneta, Kunio, Oda, Kin-ya

  Jan. 2018, Phys.Rev.D, 97(2) (2), 023523 - 023523

  Scientific journal


• Reheating in the Mixed Higgs-R² model

  Minxi He, Ryusuke Jinno, Kohei Kamada, Seong Chan Park, Alexei A. Starobinsky, Jun'ichi Yokoyama

  2018, Proceedings of the 28th Workshop on General Relativity and Gravitation in Japan, JGRG 2018, 2, 313 - 328

  International conference proceedings


• Gravitational waves from first-order phase transitions: Towards model separation by bubble nucleation rate

  Jinno, Ryusuke, Lee, Sangjun, Seong, Hyeonseok, Takimoto, Masahiro

  Nov. 2017, JCAP, 11, 050 - 050

  Scientific journal


• Hill-climbing inflation

  Jinno, Ryusuke, Kaneta, Kunio

  Aug. 2017, Phys.Rev.D, 96(4) (4), 043518 - 043518

  Scientific journal


• Violent Preheating in Inflation with Nonminimal Coupling

  Ema, Yohei, Jinno, Ryusuke, Mukaida, Kyohei, Nakayama, Kazunori

  Feb. 2017, JCAP, 02, 045 - 045

  Scientific journal


• Probing a classically conformal B-L model with gravitational waves

  Jinno, Ryusuke, Takimoto, Masahiro

  Jan. 2017, Phys.Rev.D, 95(1) (1), 015020 - 015020

  Scientific journal


• Gravitational waves from bubble collisions: An analytic derivation

  Jinno, Ryusuke, Takimoto, Masahiro

  Jan. 2017, Phys.Rev.D, 95(2) (2), 024009 - 024009

  Scientific journal


• Gravitational particle production in oscillating backgrounds and its cosmological implications

  Ema, Yohei, Jinno, Ryusuke, Mukaida, Kyohei, Nakayama, Kazunori

  Sep. 2016, Phys.Rev.D, 94(6) (6), 063517 - 063517

  Scientific journal


• Gravitational waves from the first order phase transition of the Higgs field at high energy scales

  Jinno, Ryusuke, Nakayama, Kazunori, Takimoto, Masahiro

  Feb. 2016, Phys.Rev.D, 93(4) (4), 045024 - 045024

  Scientific journal


• On adiabatic invariant in generalized Galileon theories

  Ema, Yohei, Jinno, Ryusuke, Mukaida, Kyohei, Nakayama, Kazunori

  Oct. 2015, JCAP, 10, 049 - 049

  Scientific journal


• Particle Production after Inflation with Non-minimal Derivative Coupling to Gravity

  Ema, Yohei, Jinno, Ryusuke, Mukaida, Kyohei, Nakayama, Kazunori

  Oct. 2015, JCAP, 10, 020 - 020

  Scientific journal


• Studying the Reheating Temperature after Inflation with Inflationary Gravitational Waves

  Ryusuke Jinno, Takeo Moroi, Tomo Takahashi

  Jun. 2015, NUCLEAR AND PARTICLE PHYSICS PROCEEDINGS, 263, 97 - 100, English

  [Refereed]

  International conference proceedings


• Gravitational Effects on Inflaton Decay

  Ema, Yohei, Jinno, Ryusuke, Mukaida, Kyohei, Nakayama, Kazunori

  May 2015, JCAP, 05, 038 - 038

  Scientific journal


• Diquark bound states with a completely crossed ladder truncation

  Mishima, Go, Jinno, Ryusuke, Kitahara, Teppei

  Apr. 2015, Phys.Rev.D, 91, 076011 - 076011

  Scientific journal


• Studying Inflation with Future Space-Based Gravitational Wave Detectors

  Jinno, Ryusuke, Moroi, Takeo, Takahashi, Tomo

  Dec. 2014, JCAP, 12, 006 - 006

  Scientific journal


• Cosmological Implications of High-Energy Neutrino Emission from the Decay of Long-Lived Particle

  Ema, Yohei, Jinno, Ryusuke, Moroi, Takeo

  Oct. 2014, JHEP, 10, 150 - 150

  Scientific journal


• Cosmic-Ray Neutrinos from the Decay of Long-Lived Particle and the Recent IceCube Result

  Ema, Yohei, Jinno, Ryusuke, Moroi, Takeo

  Jun. 2014, Phys.Lett.B, 733, 120 - 125

  Scientific journal


• Inflationary Gravitational Waves and the Evolution of the Early Universe

  Jinno, Ryusuke, Moroi, Takeo, Nakayama, Kazunori

  Jan. 2014, JCAP, 01, 040 - 040

  Scientific journal


• The universe dominated by oscillating scalar with non-minimal derivative coupling to gravity

  Jinno, Ryusuke, Mukaida, Kyohei, Nakayama, Kazunori

  Jan. 2014, JCAP, 01, 031 - 031

  Scientific journal


• Imprints of Cosmic Phase Transition in Inflationary Gravitational Waves

  Jinno, Ryusuke, Moroi, Takeo, Nakayama, Kazunori

  Jul. 2012, Phys.Lett.B, 713, 129 - 132

  Scientific journal


• Probing dark radiation with inflationary gravitational waves

  Jinno, Ryusuke, Moroi, Takeo, Nakayama, Kazunori

  2012, Phys.Rev.D, 86, 123502 - 123502

  Scientific journal

• LISA Cosmology Working Group

  - Present


• 素粒子論グループ

  - Present


• 理論天文学宇宙物理学懇談会

  - Present


• General Relativity and Gravitation in Japan (JGRG)

  - Present


• The Physical Society of Japan

  - Present

• 初期宇宙におけるダイナミカルな不均質形成とその重力波による検証

  Ryusuke Jinno

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grants-in-Aid for Scientific Research (C), Apr. 2024 - Mar. 2029


• Towards the real-time analysis of phase transition

  Kohei Kamada, Ryusuke Jinno

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Research (Exploratory), The University of Tokyo, Jun. 2023 - Mar. 2026


• 宇宙論的重力波による高エネルギー素粒子物理検証の研究

  Ryusuke Jinno

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Research Activity Start-up, Aug. 2023 - Mar. 2025


• 精密宇宙観測に基づいたインフレーション及び再加熱の研究

  神野 隆介

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Research Fellowships for Young Scientists (PD), Apr. 2016 - Aug. 2016

  本年度は、初期宇宙における重力波生成、及び再加熱期の粒子生成の二点を軸に研究を進めた。 前者に関しては以下の二本の論文を公表した(arXiv:1604.05035,1605.01403)。(1)素粒子模型に古典共形という性質がある場合に、初期宇宙に強い相転移及び高強度重力波生成が起こる可能性を指摘し、これが将来観測に適した強度・周波数を持つ事を示した。本研究は重力波による素粒子理論の解明可能性を与える点で重要である。(2)初期宇宙に強い相転移及びバブル生成(専門的にはrunaway)が起こる一般の場合に、生成重力波の理論的予言を確定させることは、将来観測の計画上重要である。私は、エネルギー運動量の2点関数を評価することで、従来の数値計算と同じ近似(専門的にはthin-wall・envelope)の下で重力波スペクトルが解析的に得られる事を示した。Envelope近似の妥当性に関しては議論があるが、上記方法はこれを用いない場合に拡張できるため、より精密な予言を与える改良が可能である。 後者に関しては以下の二本を公表した(arXiv:1604.08898,1609.05209)。(1)重力セクターと結合するスカラー場の宇宙論的帰結を議論した。現在の宇宙を再現するためには、このような場に強い制限がかかる事が示された。本研究は素粒子模型構築に強い制限を要求する点で重要である。(2)初期宇宙の加速膨張を引き起こした場(インフラトン)が重力と結合する場合の粒子生成を議論した。この結合は、近年LHCで発見されたヒッグス場で加速膨張を可能にする結合として研究されている。本論文では、この模型のインフラトン崩壊過程において、エネルギー移行の最重要プロセスが従来見落とされていた事を指摘した。このプロセスは元の理論に補完を要求する(専門的にはUV補完)ため、一貫した素粒子模型構築の観点から非常に重要である。 以上の論文のうち、1604.08898については雑誌掲載済、他3本はプレプリントサーバarXivに公表され、査読中である。


• 重力波を用いた素粒子論的初期宇宙の研究

  神野 隆介

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Research Fellowships for Young Scientists (DC1), Apr. 2013 - Mar. 2016

  【インフラトン起源の重力波生成】 インフレーション終了期に、インフラトンのコヒーレント振動がもたらす重力子(重力波)生成を研究した。まず、重力及びインフレーションを仮定した場合に理論的に最小限のセットアップを研究し、重力波生成が実際起こるものの、観測に足るだけの振幅を持たないことを示した。しかし、インフラトンと重力とが結合する(=最小限でない)場合には、重力子を含む特徴的な粒子生成が起こる可能性がある。そこで特に、素粒子標準模型のヒッグス場をインフラトンとして用いるような模型に現れる結合に着目し、粒子生成の解析を行った。まずこのような系を一般に解析する手法を提案した後、微分型と呼ばれる結合を持つ場合の粒子生成を研究した。結果として、理論に不安定性があること、及び重力子の共鳴生成が起こる可能性を指摘した。また、博士論文において微分型でない結合を持つ場合の解析も行った。 【ヒッグス相転移起源の重力波生成】 宇宙の相転移が重力波生成を伴う可能性は広く知られているが、標準模型ヒッグス場による相転移は非常に弱く、重力波生成も非常に少ない。一方、素粒子標準模型は自身の欠陥のため拡張が必要であり、そのような拡張において新たなスカラー場が現れることが多い。このスカラー場の存在に起因して、ヒッグスの相転移の性質が変化し、観測可能な痕跡が生まれる可能性が研究されていた。ここで私は、先行研究が「熱化」したスカラー場のみを考えていることに着目した。実はスカラー場は必ずしも「熱化」しておらず、時間変化する期待値を持って「運動」することがある。このスカラー場の時間変化が、標準模型ヒッグス場の転移スケール及びその４点結合のエネルギー依存性を変更し、相転移が１次相転移(強い相転移)となる可能性を研究した。実際、模型のパラメータによっては１次相転移が起こり、それに伴う重力波が将来的に観測可能であることが示された。