Jason Kristiano

Interest

Quantum field theory of fluctuations generated during cosmic inflation.

Keywords: Cosmic Inflation, Cosmological Perturbation, Quantum Field Theory in Curved Spacetime, Cosmological Bootstrap, and Primordial Black Holes.

Highlight

Press release of our recent paper in Physical Review Letters by School of Science, The University of Tokyo.

• Japanese: 宇宙はじめの凸凹（でこぼこ）はなぜ対称に作られたか？ [Article]
• English: Quantum nature makes spacetime fluctuations in the early Universe to be very symmetrical [Article].

Personal

• Year of Birth: 1997.
• Place of Birth: Jakarta, Indonesia.
• Nationality: Indonesian.
• Pronoun: He/Him/His.
• Language: Indonesian (Native), English (Advanced), and Japanese (Passed N3).

Education

• From October 2021: Doctor of Philosophy (Ph.D.) in Physics.
  • Institution: Department of Physics, The University of Tokyo.
  • Supervisor: Prof. Jun'ichi Yokoyama.
  • Support: JSPS DC1 Fellowship and GSGC Scholarship (Partial).
• September 2019 - September 2021: Master of Science (M.Sc.) in Physics.
  • Institution: Department of Physics, The University of Tokyo.
  • Supervisor: Prof. Jun'ichi Yokoyama.
  • Thesis: Theoretical bound on primordial non-Gaussianity in single-field inflation.
  • Support: MEXT Scholarship by University Recommendation and GSGC Scholarship (Inactive).
• August 2015 - August 2018: Bachelor of Science (S.Si.) in Physics.
  • Institution: Department of Physics, Universitas Indonesia.
  • Supervisor: Prof. Terry Mart.
  • Thesis: Pure spin-3/2 representation for use in particle and nuclear physics.
  • Support: Indonesia International Science Olympiad Scholarship.

Career

• From April 2022: Research Fellow, JSPS DC 1 Fellowship, The University of Tokyo, Japan.
• April 2019 - June 2019: Research Assistant (Internship), IBM T. J. Watson Research Center, Yorktown Heights, New York.

Reviewer

• Journal of Cosmology and Astroparticle Physics (JCAP).

Membership

• The Physical Society of Japan (JPS).
• Association of Japanese Theoretical Astronomy and Astrophysics (Rironkon).

Award

• Poster award, 2nd International Symposium on Trans-Scale Quantum Science (TSQS), The University of Tokyo, Japan, November 2022.
• Graduated cum laude with GPA 3.96/4 (the highest over all bachelor graduates) from Universitas Indonesia, August 2018.
• Bronze medal, 46th International Physics Olympiad (IPhO), Mumbai, India, July 2015.
• Honorable mention, 16th Asian Physics Olympiad (APhO), Hangzhou, China, May 2015.

Journal Article and Preprint

1. J. Kristiano and J. Yokoyama.
   Response to criticism on "Ruling Out Primordial Black Hole Formation From Single-Field Inflation": A note on bispectrum and one-loop correction in single-field inflation with primordial black hole formation.
   arXiv preprint [arXiv].
2. J. Kristiano and J. Yokoyama.
   Ruling Out Primordial Black Hole Formation From Single-Field Inflation.
   arXiv preprint [arXiv].
3. J. Kristiano and J. Yokoyama.
   Perturbative region on non-Gaussian parameter space in single-field inflation.
   Journal of Cosmology and Astroparticle Physics 07 (2022) 007 [arXiv] [Journal].
4. J. Kristiano and J. Yokoyama.
   Why Must Primordial Non-Gaussianity Be Very Small?
   Physical Review Letters 128, 061301 (2022) [arXiv] [Journal].
5. O. Gunawan, J. Kristiano, and H. Kwee.
   Magnetic-tip trap system.
   Physical Review Research 2, 013359 (2020) [arXiv] [Journal].
6. J. Kristiano, R.D. Lambaga, and H.S. Ramadhan.
   Coleman-de Luccia tunneling wave function.
   Physics Letters B 796, 225-229 (2019) [arXiv] [Journal].
7. T. Mart, J. Kristiano, and S. Clymton.
   Pure spin-3/2 representation with consistent interactions.
   Physical Review C 100, 035207 (2019) [arXiv] [Journal].
8. J. Kristiano, S. Clymton, and T. Mart.
   Pure spin-3/2 propagator for use in particle and nuclear physics.
   Physical Review C (Rapid Communication) 96, 052201 (2017) [arXiv] [Journal].

Conference Proceeding

1. A.S. Alam, J. Kristiano, R.D. Lambaga, and H.S. Ramadhan.
   Giant leaps in vacuum decay within the Dirac-Born-Infeld theory with two fields.
   Proceedings of the Conference on Theoretical Physics and Nonlinear Phenomena (CTPNP) 2019.
2. M. Mujirin, J. Kristiano, and T. Mart.
   Pure spin-5/2 propagator from the antisymmetric tensor spinor formalism.
   Proceedings of the Conference on Theoretical Physics and Nonlinear Phenomena (CTPNP) 2019.
3. J. Kristiano and T. Mart.
   Path integral quantization of an interacting pure spin-3/2 field.
   Proceedings of the 4th International Symposium on Current Progress in Mathematics and Sciences (ISCPMS) 2018.
4. J. Kristiano and T. Mart.
   Massive particle spin-3/2 propagator.
   Proceedings of the 3rd International Symposium on Current Progress in Mathematics and Sciences (ISCPMS) 2017.

Conference

1. Progress on one-loop correction in PBH formation from single-field inflation.
   Revisiting cosmological non-linearities in the era of precision surveys (YITP International Molecule-type Workshop), Kyoto University, Japan, July 2023.
2. Bispectrum and one-loop correction in PBH formation from single-field inflation.
   Non-linear Nature of Cosmological Perturbations and its Observational Consequences (YITP Domestic Molecule-type Workshop), Kyoto University, Japan, March 2023.
3. Ruling out primordial black hole formation from single-field inflation.
   Dynamics of Primordial Black Hole Formation Workshop, Rikkyo University, Japan, March 2023.
4. Primordial black holes from single-field inflation?
   Cosmology and Particle Astrophysics (CosPA), Asia Pacific Center for Theoretical Physics (APCTP), South Korea, November 2022 (Online).

Seminar

1. Bispectrum and one-loop correction in PBH formation from single-field inflation.
   Department of Physics (Particle Theory and Cosmology Group) Seminar, Tohoku University, Japan, May 2023.
2. Exploring possibilities of the inflationary potential.
   Rikkyo University Colloquium, Japan, April 2023.
3. Primordial black holes from single-field inflation?
   Leung Center for Cosmology and Particle Astrophysics (LeCosPa) Seminar, National Taiwan University, Taiwan, April 2023 (Online).
4. Bispectrum and one-loop correction in PBH formation from single-field inflation.
   Zooming in on Primordial Black Holes Seminar, Leiden University, The Netherlands, April 2023 (Online).
5. Ruling out primordial black hole formation from single-field inflation.
   Theory Group Seminar, High Energy Accelerator Research Organization (KEK), Japan, March 2023.
6. Ruling out primordial black hole formation from single-field inflation.
   Institute of Theoretical Physics Seminar, Chinese Academy of Sciences, China, February 2023 (Online).
7. Ruling out primordial black hole formation from single-field inflation.
   Department of Physics (C-Lab) Seminar, Nagoya University, Japan, January 2023.
8. One-loop perturbativity bound as a constraint on single-field inflation and primordial black hole formation.
   Department of Physics (High Energy Theory Group) Seminar, The University of Athens, Greece, December 2022 (Online).
9. One-loop perturbativity bound in single-field inflation.
   Department of Physics (Particle Theory Group) Seminar, The University of Tokyo, Japan, November 2022.
10. What happened before the Big Bang?
    Department of Physics Seminar, Universitas Indonesia, Indonesia, March 2022 (Online).

Oral Presentation

1. Superhorizon evolution of the squeezed bispectrum.
   The 32nd Workshop on General Relativity and Gravitation in Japan (JGRG), Nagoya University, Japan, November 2023.
2. One-loop correction in primordial black hole formation from single-field inflation.
   Focus Week on Primordial Black Holes, Kavli IPMU, Japan, November 2023.
3. Superhorizon evolution of the squeezed bispectrum.
   Correlators in Cortona, Italy, September 2023.
4. One-loop correction in primordial black hole formation from single-field inflation.
   The 26th International Conference on Particle Physics and Cosmology (COSMO), Instituto de Física Teórica, Spain, September 2023.
5. Ruling out primordial black hole formation from single-field inflation.
   The 79th Physical Society of Japan (JPS) Meeting, Japan, March 2023 (Online).
6. Ruling out primordial black hole formation from single-field inflation.
   Joint Workshop on General Relativity and Cosmology (JGRC), Okutama, Japan, March 2023.
7. Ruling out primordial black hole formation from single-field inflation.
   Early Universe Mini-Workshop, Kobe RIKEN, Japan, January 2023.
8. One-loop perturbativity bound in single-field inflation.
   The 31st Workshop on General Relativity and Gravitation in Japan (JGRG), The University of Tokyo, Japan, October 2022.
9. One-loop perturbativity bound in single-field inflation.
   The 26th International Summer Institute on Phenomenology of Elementary Particle Physics and Cosmology, Fuji-Yoshida, Japan, September 2022.
10. Perturbative region on non-Gaussian parameter space in single-field inflation.
    The 78th Physical Society of Japan (JPS) Meeting, Okayama University of Science, Japan, September 2022.
11. Perturbative region on non-Gaussian parameter space in single-field inflation.
    The 15th Asia-Pacific Physics Conference (APPC), South Korea, August 2022 (Online).
12. Theoretical bound on primordial non-Gaussianity in single-field inflation.
    The 77th Physical Society of Japan (JPS) Meeting, Japan, March 2022 (Online).
13. Theoretical bound on primordial non-Gaussianity in single-field inflation.
    The 30th Workshop on General Relativity and Gravitation in Japan (JGRG), Waseda University, Japan, December 2021 (Online).
14. Theoretical bound on primordial non-Gaussianity in single-field inflation.
    Recent Progress of Quantum Cosmology (YITP Workshop), Kyoto University, Japan, November 2021 (Online).
15. Coleman-de Luccia tunneling wave function.
    The 14th Asia-Pacific Physics Conference (APPC), Kuching, Malaysia, November 2019.
16. Coleman-de Luccia tunneling wave function.
    Conference on Theoretical Physics and Nonlinear Phenomena (CTPNP), Makasar, Indonesia, July 2018.
17. Path integral quantization of an interacting pure spin-3/2 field.
    The 4th International Symposium on Current Progress in Mathematics and Sciences (ISCPMS), Depok, Indonesia, July 2018.
18. Massive particle spin-3/2 propagator.
    The 3rd International Symposium on Current Progress in Mathematics and Sciences (ISCPMS), Bali, Indonesia, July 2017.

Poster Presentation

1. One-loop perturbativity bound in single-field inflation.
   2nd International Symposium on Trans-Scale Quantum Science (TSQS), The University of Tokyo, Japan, November 2022.
2. Theoretical bound on primordial non-Gaussianity in single-field inflation.
   The 24th International Conference on Particle Physics and Cosmology (COSMO), University of Illinois, United States, August 2021 (Online).
3. Pure spin-3/2 propagator for use in particle and nuclear physics.
   The 8th International Conference on Quark and Nuclear Physics (QNP), Tsukuba, Japan, November 2018.

Research Related

• Quantum nature makes spacetime fluctuations in the early Universe to be very symmetrical, The University of Tokyo Press Release, March 2022 [Article].
• 宇宙はじめの凸凹（でこぼこ）はなぜ対称に作られたか？, The University of Tokyo Press Release, February 2022 [Article].
• 東大、宇宙はじめの凸凹（でこぼこ）はなぜ対称に作られたかを解明, NIKKEI, February 2022 [Article].
• 宇宙はじめの凸凹はなぜ対称に作られたか、東大チームが解析, MIT Technology Review Japan, February 2022 [Article].

Personal Related

• The highest GPA over all bachelor graduates, Universitas Indonesia News, September 2018 [Article].
• Optimistic young researcher, Kompas Newspaper, January 2018 [Article].
• Profile (Indonesian: Sosok), Kompas Newspaper, November 2017 [Article].
• Bronze medalist of International Physics Olympiad (IPhO) 2015, Media Indonesia, July 2015 [Article].