Probing quantumness of primordial gravitational waves with quantum information theory

• Project/Area Number: 17K18778
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Particle-, Nuclear-, Astro-physics, and related fields
• Research Institution: Kobe University
• Principal Investigator: Soda Jiro 神戸大学, 理学研究科, 教授 (00222076)
• Project Period (FY): 2017-06-30 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000); Fiscal Year 2019: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000); Fiscal Year 2018: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000); Fiscal Year 2017: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
• Keywords: 原始重力波 / 量子性 / 量子情報 / インフレーション / グラビトン / エンタングルメント / 重力波 / 高周波数 / マグノン / 高次量子干渉 / サブポアッソン分布 / 宇宙物理 / 素粒子論

Outline of Final Research Achievements

We clarified the importance of Mermin's inequality and the staticis of gravitons for characterizing non-classicality of fluctuations generated during inflation.
Inflation predicts that the quantum state of gravitons is a squeezed state. We studied the effect of quantum fluctuations on a heavy particle and showed that the gravitons induce decoherence of the quantum coherence of the particle. Based on our results, we proposed a concrete experimental setup for detecting gravitons. The paper is selected as Editors' suggestion of Phsical Review D. This clearly shows our work is recognized by the community in the world.

Academic Significance and Societal Importance of the Research Achievements

揺らぎの量子性を直接検証することにより、インフレーション理論を確立することは宇宙論の最重要課題となっている。また、グラビトンの発見は量子重力理論研究にとって最重要課題となっている。
本研究では、量子情報理論を用いたインフレーションの完全な証明の可能性を明確に示した。特に、マーミンの不等式とグラビトンの統計性の宇宙論的な意義を見出した点は重要な成果である。また、グラビトンの量子揺らぎによる重い物体のデコヒーレンスの研究を基礎として、未だその存在が証明されていないグラビトンの検出方法を発見したことは、量子重力理論研究への大きな貢献とみなせる。

Research Products

• [Int'l Joint Research] ソウル大学(韓国)
• [Int'l Joint Research] ビーフェルト大学(ドイツ)
• [Int'l Joint Research] バスク大学(スペイン)
• [Journal Article] Nano-Hz Gravitational-Wave Signature from Axion Dark Matter (2021)
  • Author(s): Kitajima Naoya、Soda Jiro、Urakawa Yuko
  • Journal Title: Physical Review Letters Volume: 126 Issue: 12 Pages: 121301-121301
  • DOI: 10.1103/physrevlett.126.121301
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] O(d,d;Z) invariant Fierz-Pauli massive gravity (2021)
  • Author(s): Noumi Toshifumi、Saito Kaishu、Soda Jiro、Yoshida Daisuke
  • Journal Title: Physical Review D Volume: 103 Issue: 4 Pages: 1-8
  • DOI: 10.1103/physrevd.103.046011
  • NAID: 120006993638
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Analytic formula for the dynamics around inflation end and implications on primordial gravitational waves (2021)
  • Author(s): Ito Asuka、Soda Jiro、Yamaguchi Masahide
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2021 Issue: 03 Pages: 033-033
  • DOI: 10.1088/1475-7516/2021/03/033
  • Peer Reviewed / Open Access
• [Journal Article] Noise and decoherence induced by gravitons (2021)
  • Author(s): Kanno Sugumi、Soda Jiro、Tokuda Junsei
  • Journal Title: Physical Review D Volume: 103 Issue: 4 Pages: 044017-044017
  • DOI: 10.1103/physrevd.103.044017
  • Peer Reviewed / Open Access
• [Journal Article] Stability of magnetic black holes in general nonlinear electrodynamics (2020)
  • Author(s): Nomura Kimihiro、Yoshida Daisuke、Soda Jiro
  • Journal Title: Physical Review D Volume: 101 Issue: 12 Pages: 1-21
  • DOI: 10.1103/physrevd.101.124026
  • NAID: 120006894041
  • Peer Reviewed / Open Access
• [Journal Article] A formalism for magnon gravitational wave detectors (2020)
  • Author(s): Ito Asuka、Soda Jiro
  • Journal Title: The European Physical Journal C Volume: 80 Issue: 6 Pages: 545-545
  • DOI: 10.1140/epjc/s10052-020-8092-6
  • NAID: 120006873019
  • Peer Reviewed / Open Access
• [Journal Article] Constraining the gravitational coupling of axion dark matter at LIGO (2020)
  • Author(s): Jung Sunghoon、Kim TaeHun、Soda Jiro、Urakawa Yuko
  • Journal Title: Physical Review D Volume: 102 Issue: 5 Pages: 1-15
  • DOI: 10.1103/physrevd.102.055013
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Pulsar timing residual induced by ultralight vector dark matter (2020)
  • Author(s): Nomura Kimihiro、Ito Asuka、Soda Jiro
  • Journal Title: The European Physical Journal C Volume: 80 Issue: 5 Pages: 419-419
  • DOI: 10.1140/epjc/s10052-020-7990-y
  • NAID: 120006846527
  • Peer Reviewed / Open Access
• [Journal Article] Stability of axion dark matter-photon conversion (2020)
  • Author(s): Masaki Emi、Aoki Arata、Soda Jiro
  • Journal Title: Physical Review D Volume: 101 Issue: 4 Pages: 043505-043505
  • DOI: 10.1103/physrevd.101.043505
  • NAID: 120006796518
  • Peer Reviewed / Open Access
• [Journal Article] Probing GHz gravitational waves with graviton?magnon resonance (2020)
  • Author(s): Ito Asuka、Ikeda Tomonori、Miuchi Kentaro、Soda Jiro
  • Journal Title: The European Physical Journal C Volume: 80 Issue: 3 Pages: 179-179
  • DOI: 10.1140/epjc/s10052-020-7735-y
  • NAID: 120006823974
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Birth of de Sitter universe from a time crystal universe (2019)
  • Author(s): Yoshida Daisuke、Soda Jiro
  • Journal Title: Physical Review D Volume: 100 Issue: 12 Pages: 123531-123531
  • DOI: 10.1103/physrevd.100.123531
  • NAID: 120006796517
  • Peer Reviewed / Open Access
• [Journal Article] Accelerating universe with a stable extra dimension in cuscuton gravity (2019)
  • Author(s): Ito Asuka、Sakakihara Yuki、Soda Jiro
  • Journal Title: Physical Review D Volume: 100 Issue: 6 Pages: 063531-063531
  • DOI: 10.1103/physrevd.100.063531
  • NAID: 120006796519
  • Peer Reviewed / Open Access
• [Journal Article] Searching for Bispectrum of Stochastic Gravitational Waves with Pulsar Timing Arrays (2019)
  • Author(s): Tsuneto Makoto、Ito Asuka、Noumi Toshifumi、Soda Jiro
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 1903 Issue: 03 Pages: 032-032
  • DOI: 10.1088/1475-7516/2019/03/032
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Quasinormal modes of p-forms in spherical black holes (2019)
  • Author(s): Yoshida Daiske、Soda Jiro
  • Journal Title: Physical Review D Volume: 99 Issue: 4 Pages: 044054-044054
  • DOI: 10.1103/physrevd.99.044054
  • NAID: 120006715550
  • Peer Reviewed / Open Access
• [Journal Article] Exploring the string axiverse and parity violation in gravity with gravitational waves (2018)
  • Author(s): Yoshida Daiske , Soda Jiro
  • Journal Title: International Journal of Modern Physics D Volume: - Issue: 09 Pages: 1850096-1850096
  • DOI: 10.1142/s0218271818500967
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Cosmological imprints of string axions in plateau (2018)
  • Author(s): Soda Jiro、Urakawa Yuko
  • Journal Title: The European Physical Journal C Volume: 78 Issue: 9 Pages: 779-779
  • DOI: 10.1140/epjc/s10052-018-6246-6
  • NAID: 120006529677
  • Peer Reviewed / Open Access
• [Journal Article] Electromagnetic waves propagating in the string axiverse (2018)
  • Author(s): Yoshida Daiske , Soda Jiro
  • Journal Title: Progress of Theoretical and Experimental Physics Volume: 2018 Issue: 4 Pages: 1-10
  • DOI: 10.1093/ptep/pty029
  • Peer Reviewed / Open Access
• [Journal Article] Anisotropic constant-roll Inflation (2018)
  • Author(s): Ito Asuka、Soda Jiro
  • Journal Title: The European Physical Journal C Volume: 78 Issue: 1 Pages: 1-6
  • DOI: 10.1140/epjc/s10052-018-5534-5
  • Peer Reviewed / Open Access
• [Journal Article] Conversion of gravitons into dark photons in cosmological dark magnetic fields (2018)
  • Author(s): Masaki Emi、Soda Jiro
  • Journal Title: Physical Review D Volume: 98 Issue: 2 Pages: 023540-023540
  • DOI: 10.1103/physrevd.98.023540
  • NAID: 120006501236
  • Peer Reviewed
• [Journal Article] Gravitational wave forest from string axiverse (2018)
  • Author(s): Kitajima Naoya、Soda Jiro、Urakawa Yuko
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2018 Issue: 10 Pages: 008-008
  • DOI: 10.1088/1475-7516/2018/10/008
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Schwinger pair production by electric field coupled to inflaton (2018)
  • Author(s): Geng Jia-Jia、Li Bao-Fei、Soda Jiro、Wang Anzhong、Wu Qiang、Zhu Tao
  • Journal Title: Journal of Cosmology and Astroparticle Physics Volume: 2018 Issue: 02 Pages: 018-018
  • DOI: 10.1088/1475-7516/2018/02/018
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Bell Inequality and Its Application to Cosmology (2017)
  • Author(s): Kanno Sugumi、Soda Jiro
  • Journal Title: Galaxies Volume: 5 Issue: 4 Pages: 99-99
  • DOI: 10.3390/galaxies5040099
  • NAID: 120006382339
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Infinite violation of Bell inequalities in inflation (2017)
  • Author(s): Kanno Sugumi、Soda Jiro
  • Journal Title: Physical Review D Volume: 96 Issue: 8 Pages: 083501-083501
  • DOI: 10.1103/physrevd.96.083501
  • NAID: 120006366532
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Probing ultralight vector dark matter (2020)
  • Author(s): Jiro Soda
  • Organizer: Dark Odyssey 2020
  • Int'l Joint Research / Invited
• [Presentation] Fun with a cuscuton (2019)
  • Author(s): Jiro Soda
  • Organizer: International workshop for String Theory and Cosmology
  • Int'l Joint Research / Invited
• [Presentation] Inflation with broken rotational symmetry and graviton statistics (2019)
  • Author(s): Jiro Soda
  • Organizer: Symmetry 2019
  • Int'l Joint Research / Invited
• [Presentation] Effective Field Theory of Anisotropic Inflation (2019)
  • Author(s): Jiro Soda
  • Organizer: 6th Korea-Japan workshop on dark energy at KMI
  • Int'l Joint Research / Invited
• [Presentation] Beyond anisotropic inflation (2019)
  • Author(s): Jiro Soda
  • Organizer: ACGRG 10
  • Int'l Joint Research
• [Presentation] Parity Violation in Gravity: probing with gravitational waves (2019)
  • Author(s): Jiro Soda
  • Organizer: Area workshop 2019 winter
  • Int'l Joint Research
• [Presentation] Detectability of gravitons with HBT interferometers (2019)
  • Author(s): Jiro Soda
  • Organizer: 新学術「加速宇宙」シンポジウム
  • Int'l Joint Research
• [Presentation] 原始重力波の量子コヒーレンス (2018)
  • Author(s): 早田次郎
  • Organizer: 研究会「量子情報と宇宙」
• [Presentation] Cosmological Bell Inequality and Entangled Quantum Vacuum (2018)
  • Author(s): Jiro Soda
  • Organizer: International workshop for String Theory and Cosmology
  • Int'l Joint Research / Invited
• [Presentation] Glauber in the Sky (2018)
  • Author(s): Jiro Soda
  • Organizer: The first NRF-JSPS workshop in particle physics,cosmology, and gravitation
  • Int'l Joint Research / Invited
• [Presentation] Gravitational wave forest from the string axiverse (2018)
  • Author(s): Jiro Soda
  • Organizer: SUSY 2018
  • Int'l Joint Research
• [Presentation] String Axions, Flapping resonance, and GW forest (2018)
  • Author(s): Jiro Soda
  • Organizer: 5th Korea-Japan workshop on dark energy
  • Int'l Joint Research / Invited
• [Presentation] Primordial Gravitational Waves (2018)
  • Author(s): Jiro Soda
  • Organizer: String axion workshop
  • Int'l Joint Research / Invited
• [Presentation] Nonclassicality of Primordial Gravitational Waves (2018)
  • Author(s): Jiro Soda
  • Organizer: 2nd annual area symposium
  • Int'l Joint Research
• [Presentation] 物理学は宇宙大規模構造の起源を明らかにできるか？ (2018)
  • Author(s): 早田次郎
  • Organizer: 理論懇シンポジウム
  • Invited
• [Presentation] String moduli, string axiverse, and gravitational waves (2018)
  • Author(s): Jiro Soda
  • Organizer: 7th Bangkok Workshop on High-Energy Theory
  • Int'l Joint Research
• [Presentation] 原始重力波の量子コヒーレンス (2018)
  • Author(s): 早田次郎、菅野優美
  • Organizer: 日本物理学会
• [Presentation] ベルの不等式関連の話 (2017)
  • Author(s): 早田次郎
  • Organizer: 曲がった時空上の場の量子論と量子情報
  • Invited
• [Presentation] Exploring string axiverse with gravitational wave physics (2017)
  • Author(s): Jiro Soda
  • Organizer: IV Cosmology and the Quantum Vacuum 2017
  • Int'l Joint Research / Invited
• [Presentation] Infinite violation of Bell inequalities (2017)
  • Author(s): 早田次郎、菅野優美
  • Organizer: 日本物理学会
• [Presentation] Gravitational waves in the string axiverse (2017)
  • Author(s): Jiro Soda
  • Organizer: NCTS Annual meeting 2017
  • Int'l Joint Research / Invited