Professor KOHRI, Kazunori
Research Field
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The Early Universe, Cosmology, Black Holes, Astro-Particle Physics
Degree
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Ph. D in Physics
Summary of Research
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I specialize in theoretical research that uses particle physics to reveal the beginning of the universe and the mysteries that occur in compact objects such as black holes. My research uses quantum field theory, general relativity, mathematics, and so on. The Universe was born 13.8 billion years ago and expanded from a fireball state called the Big Bang to its current large form. The fireball was created at a cosmic age of shorter than about 0.01 second and at a temperature of at least 100 billion degrees Celsius/Kelvin, which cannot be understood without the use of particle physics. Also, before the fireball was formed, there was a period known as inflation, when the Universe expanded faster than the speed of light. It is believed that undiscovered new scalar fields are also responsible for inflation. The energy that makes up the universe today consists of only about 5% of the visible matter that makes up stars and the Sun, about 25% of dark matter, and about 70% of dark energy, which can even be no longer called matter. I am working to answer the questions 1) what are the elementary particles that cause inflation?, 2) what are dark matter and dark energy? and 3) why there is more ordinary matter than anti-matter.
Research Achievements or Papers
- Kohri, K. and Terada, T., "Semianalytic calculation of gravitational wave spectrum nonlinearly induced from primordial curvature perturbations", Physical Review D, Volume 97, Issue 12, id.123532
- Kawasaki, M., Kohri, K. and Moroi, T., "Big-bang nucleosynthesis and hadronic decay of long-lived massive particles", Physical Review D, vol. 71, Issue 8, id. 083502,
- Carr, B. J. ; Kohri, K., Sendouda, Y., Yokoyama, J., "New cosmological constraints on primordial black holes", Physical Review D, vol. 81, Issue 10, id. 104019
- Kohri, K. and Mineshige, S., "Can Neutrino-cooled Accretion Disks Be an Origin of Gamma-Ray Bursts"?, The Astrophysical Journal, Volume 577, Issue 1, pp. 311-321
Academic Society
- ASJ, JPS
Academic Award
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The 2013 Yukawa-Kimura Prize
http://www2.yukawa.kyoto-u.ac.jp/~kimurasho.oj/kimurasho/rsn/13e.htm -
The 2020 (The 25th) Outstanding Paper Award of the Physical Society of Japan Citation
https://www.jps.or.jp/english/meetings-and-awards/awards/ronbunsyo/ronbun25-2020.html
Other Activity
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[Press Release] MAGIC Telescopes scrutinize the center of our home Galaxy for fingerprints of dark matter
https://www.icrr.u-tokyo.ac.jp/en/news/13146/ -
[Press Release] Researchers find way to show how the tiniest particles in our Universe saved us from complete annihilation
https://www.ipmu.jp/en/20200204-cosmicstringsgw -
The KEK Open Campus 2022, Professor Makoto Kobayashi's Cup Quiz Competition 2022 Online (2022.09.03)
https://live.nicovideo.jp/watch/lv338041117
Web Page
- kazunori.kohri[at]gmail.com
(In the mailing address, replace [at] with @)