See「Recent topics/最近の話題」 for recent news.「Recent topics/最近の話題」では主に、最近arXivに出した私達の論文の軽い背景説明や、参加した研究会等の話題や、また研究関連のニュース記事などを定期的に書いていこうと思います。定期的にアップデートしています。


My new homepage was presented to the public/ホームページを公開しました。

About me




Welcome to my new homepage!

I am Nori Iizuka, a theoretical physicist working at Osaka, Japan. Currently I am working at department of physics at Osaka University, conducting research on theoretical and mathematical physics, especially *string theory*.
Extremely simply put, string theory is a theory of strings, where we regard all (apparently point-like) particles made up by vibrating one-dimensional strings. Quite remarkably, by making this theory of vibrating strings mathematically completely consistent with the principles of quantum mechanics and (1+1)-dimensional general relativity, you are forced to see an ultimate theory of theoretical physics, which contains higher dimensional gravity (i.e., Einstein's general relativity), weak force, strong force, extra dimensions (meaning that our space-time has more than 3 spatial directions!), supersymmetry, black holes (space-time regions where gravitational force is so strong that nobody, even a light beam cannot escape from that at least classically), wormholes (a space-time structure where different points are connected), emergent space-time and holography (These are very modern physics so I will explain it more later), and many beautiful mathematics. String theory is an extremely rich and deep subject!

Among all, the most interesting aspects of string theory to me is its gravitational aspects, namely, string theory as a theory of *quantum gravity*, an ultimate theory to describe Einstein's theory of gravity and space-time according to the principles of quantum mechanics. My past research achievements were to shed new light on the aspects of quantum gravity and space-time, including finding new attractor mechanism for black holes and also finding a new model of quantum black holes clarifying the 'mistakes' of Stephen Hawking's black hole evaporation.

In this homepage, I would like to explain briefly what these theories are and why we theoretical physicists are working on these so hard. For experts who is currently working on these and possibly seeking for the post-doc position, I would also like to explain what kind of stuff especially in string theory I am working on. But of course, if you are beginning undergrad student or advanced high school student, I am sure that you do not know what these theories are, but that's also completely OK! I will also explain these for much simpler ways and as intuitive as possible. If you are in the 3rd year on your undergrad study and seeking for your future research directions, my homepage might help you to understand why string theory and quantum gravity is such an exciting field and you youngsters should think of challenging it.

I would also like to show some useful informations about international workshops or my talk slide about recent development in this homepage as well. In such ways, I hope my homepage becomes useful for various level of people, high school students/undergrad university students/Ph.D. students/postdoc/senior faculties. Hope you enjoy this new homepage!





その様な非常に豊かな構造を示す魅力的な弦理論の中でも特に私が興味をもっているのが量子重力理論としての弦理論の側面です。 このホームページでは、私の研究している「弦理論、量子重力理論」について、(高校で物理を勉強しているアドバンスな)高校生向け/(大学で物理を勉強している)大学生向け/実際に弦理論の研究に携わっている大学院生や研究者向けと段階的に様々なレベルで紹介していこうと思っています。


物理学専攻 助教

飯塚 則裕

Assistant Professors,
Osaka Univ. Particle Physics Theory Group



~ life is a journey ~


I was born in Kishiwada-city, a southern city of Osaka prefecture. After the high school, in 1994, I enrolled in the University of Tokyo and graduated it in 1998. Then I went to the graduate school again at the University of Tokyo till 1999 summer. After that, I moved to New York in US for my PhD course at Columbia University. I was extremely fortunate that I met Prof. Daniel Kabat, my great mentor and also my great collaborator now, at Columbia. He is really a great person and through a lot of helpful discussion with him, I have learned quite a lot on string theory, quantum nature of black holes, and holography, during my PhD.

In 2003, I obtained my PhD, my PhD thesis title is, "Holographic description of quantum black holes and spacetime".

After obtaining my PhD at Columbia, my world-wide post-doc career started. In 2003 summer, from New York, I flew to Mumbai, India, to begin my first post-doc at Tata Institute for Fundamental Research, so-called TIFR. At that moment, I guess that TIFR is one of the top string theory group in the world, probably one of the top 5 in the world. While I was in India, I was again extremely fortunate that I have worked with many great string theorists there, including Prof. Sandip Trivedi (former director of the Tata Institute (2015-2020) and even now he is my great collaborator!) and Prof. Atish Dabholkar (current director at ICTP, Trieste), Prof. Ashoke Sen, and many other great string theorists, and I have learned a lot of physics and math from them. Also working and living in India is, in my personal opinion, one of the great experience in my life and I really enjoyed it! To be honest, before I went to India, I have strong hesitation to go due to my ignorance, but by looking back I think deciding to go to India is one of my best decision in my life. (I travelled many places in India from Kanyakumari, the southern tip of the Indian subcontinent, to northern Himalayas, Ganges etc. There is a quote, “The world is a book, and those who do not travel read only one page.” by St Augustine. I think that is right.)

In 2006, after a very nice faraway to my friends in India, and stopping over my good friend in Greece, I moved to US, but this time, to the west coast to work for my second postdoc at Kavli Institute of Theoretical Physics at the University of California, Santa Barbara. It is a world-famous theoretical physics institute where director at that time was Noble prize laureate Prof. David Gross. I was again fortunate to work with late Prof. Joe Polchinski, an extremely famous string theorist who found 'D-brane' and write a famous Joe's big book of string theory. We together worked on a toy model of holography (so-called I(izuka)-P(olchinski) model) and investigated quantum nature of black holes through our models.

In 2009, I moved to CERN, very famous international research center on the France–Switzerland border, to work as a fellow (Non-member-state (since Japan is not a member state for CERN) fellowship and in addition, I also obtained a special COFUND fellowship very fortunately). In addition, while I was there, a world famous particle accelerator, Large Hadron Collider (LHC) found Higgs particles. Then in 2012, I moved to Yukawa Institute, and in 2013, to RIKEN, and after 2014, I am currently at Osaka.

In total, I spent 13 years in foreign countries (4 years in US for PhD, 3 years in India, 3 years in US, and finally 3 years in Europe). Consequently, regarding the way I do physics is, I feel that I am more close to foreign researchers than typical Japanese researchers.

After I joined Osaka, I was again extremely lucky that I had many talented young grad students. To name just a few, Kotaro Tamaoka was one of my first grad student at Osaka. He is talented and passionate to physics. He is very successful in his career and now he is assistant professor at Nihon University. Currently I have another extremely talented grad student, Takanori Anegawa (now JSPS fellow). But other than these, I also had many other young and talented students. In addition, currently I have new postdoc, Dr. Sunil Kumar Sake from TIFR (Sandip's ex-student) and Dr. Nicolo Zenoni from Italy and with these very talented young collaborators, we are working hard to understand and unravel the mysteries of gravity, space-time, and quantum black holes.



1999年8月から東京大学の大学院を休学し(数年後中退しました)、渡米しアメリカ、コロンビア大学大学院、 department of physicsのPh.D.課程に入学しました。そのころ若い教員としてコロンビアに新たに着任された Dan(iel) Kabatさんの指導のもと、弦理論、ブラックホールの量子論について大いに学ぶことができました。

2003年8月、コロンビア大学にてPh.D.習得(書類の上での卒業はその年の10月)。Ph.D. thesisは「Holographic description of quantum black holes and spacetime」(日本語訳:ホログラフィーによる量子ブラックホールと時空の記述)です。良き指導教官に出会えたのは非常に幸運だったと思ってます。

2003年9月から最初のポスドクとしてインドの タタ研究所(TIFR)に着任。Sandip Trivediさん(2022年現在、タタ研究所前所長)、Atish Dabholkarさん(2022年現在、イタリアICTP研究所の所長)やAshoke Senさん他、すばらしい先生方や他のポスドクの方と非常に充実した研究生活をさせてもらいました。タタ研究所は当時世界で5本の指に入るほど素晴らしい研究環境であったと思います。コロンビア大学でのDanの指導と、first postdocとしてのタタ研究所での研究が研究者としての私の原点だと思います。

2006年9月からは2回目のポスドクとしてアメリカカリフォルニアサンタバーバラにあるKavli理論物理学研究所(KITP)に着任。今は亡きJoseph Polchinskiさんとも共同研究でき、非常に勉強になりました。

2009年9月からは加速器で世界的に有名なスイスにあるCERN(欧州原子核研究機構)にて3回目のポスドクをしました。そこでのポジションはNon-member- state fellow(日本はCERNにnon-member stateとして参加している)に加え、Cofund fellowという特別なフェローシップも追加でいただき、通常のCERNのポスドクの2年ではなく3年の特別なポジションにしていただきました。

2012年9月からは日本に帰り、京都大学基礎物理学研究所、 2013年、9月からは理研にてスタッフ研究員を経由し、2014年から大阪大学に助教として着任し現在に至ります。


また大阪大学に来てから何人もの大学院生を指導しています。中でも着任してすぐ私の最初の学生になった一人である玉岡幸太郎君は、非常に優秀で2021年4月からめでたく日本大学で教員(Assistant professor)のポジションを得ました。また最近卒業された姉川尊徳君は、Doctor1年目から日本学術振興会特別研究員(いわゆるDC1)に選ばれ、Doctor3年時には、大阪大学大学院理学研究科優秀研究賞を受賞するなど非常に優秀で、2024年からは米子高専でめでたく教員(Assistant professor)のポジションを得ました。さらに2022年秋からは海外のポスドクも二人きてくれています(インドからSunil Kumar Sakeさん (Sandipさんの下でPhD)、そしてイタリアからNicolo Zenoniさん)。このように才能に溢れた若い学生、ポスドク、および世界のたくさんの共同研究者とともに私たちは日々、量子重力の謎、時空の謎、ブラックホールの謎にせまるべく研究をしています。



My students


My past PhD students/過去に研究指導してきた大学院生

Dr. Takanori Anegawa/姉川 尊徳
Currently (as of 2024) an assistant professor at Yonago College/大阪大学で博士号習得後、米子工業高等専門学校助教(教員)
2024/03 PhD/博士号:Thesis title/論文題目「Research on hyperfast growth in de Sitter complexity」
2021年4月より3年間、日本学術振興会特別研究員(DC1), JSPS fellow for 3 years
2021/03 MA/修士号:Thesis title/論文題目「Information paradox and island prescription」
2019/03 BA/卒業研究指導 Thesis title/卒論題目:「Black Hole and Information Paradox」

Dr. Kotaro Tamaoka/玉岡 幸太郎
Currently (as of 2024) an assistant professor at Nihon University/大阪大学で博士号習得後、京都大学基礎物理学研究所素粒子論特定研究員を経て現在は日本大学文理学部物理学科助教(教員)
2019/03 PhD/博士号:Thesis title/論文題目「Emergence of Bulk Geometries from Conformal Field Theory」
2016/03 MA/修士号:Thesis title/論文題目「Black Hole Entropy and three dimensional gravity/3次元重力理論とブラックホールエントロピー」

Dr. Tsuyoshi Yokoya/横矢 毅
2019/03 PhD/博士号:Thesis title/論文題目「Analysis on entanglement entropy for two-dimensional lattice gauge theories with matter fields」
2016/03 MA/修士号:Thesis title/論文題目「Breaking of supersymmetry through Witten index/Witten indexによる超対称性の破れの評価」

My past graduate students for MA/過去に研究指導してきた大学院生

坂川 友亮
2022年3月 MA/修士号:論文題目「AdS/CFT 対応における線形重力方程式の量子情報的関係式による導出 (Derivation of linearized Einstein equation using quantum information theory in AdS/CFT)」

毛受 正裕
2021年3月 MA/修士号:論文題目「Recent works about Superconformal Index and Blackhole entropy」
2019年3月 BA/卒業研究指導 卒論題目:「ブラックホールエントロピーとBekenstein Bound (Black hole entropy and Bekenstein Bound)」

西川 航平
2021年3月 MA/修士号:論文題目「ブラックホールの形成の臨界点における問題」
BA/卒業研究指導 卒論題目:「Reissner-Nordström解の不安定性」

東出 和也
2018年3月 MA/修士号:論文題目「境界相関関数によるAdSブラックホールの解析」



Principal Investigator/獲得資金:代表

1. MEXT KAKENHI Grant-in-Aid for Transformative Research Areas A Extreme Universe No.21H05184
学術変革領域研究(A)研究計画班 代表
Transformative Research Areas, Section (II)
●From 2021 - 2026
●2022年度から4年間、2名のポスドク(Sunil Kumar SakeさんとNicolo Zenoniさん)を私の下で雇用。

MEXT -KAKENHI- Grant-in-Aid for Transformative Research Areas (A)
The Natural Laws of Extreme Universe -A New Paradigm for Spacetime and Matter from Quantum Information

2. Grant-in-Aid for Scientific Research (C) No. 18K03619/科研費 基盤C 代表

3. Grant-in-Aid for Young Scientists (B)/科研費 若手B 代表
(課題名:Solving Condensed Matter, Nuclear and Gravity Problems via String and Gauge/Gravity Duality/

4. CERN Non-member state fellowship and cofund fellowship(2009 - 2012)


1. 科研費 基盤C(分担)(2017 to 2019 課題名:微分展開方を用いた新しいブラックホール解への解析的アプローチ)

2. 科研費 基盤C(分担)(2014 to 2016 課題名:非線形物理現象へのAdS/CFT双対性の応用)


1. sg-l 海外オブザーバー担当係(2015年、2016年)

Building H-721, Toyonaka campus
1-1 Machikaneyama, Toyonaka Osaka 560-0043, Japan
Tel: +81-6-6850-5730
Mail:iizuka★phys.sci.osaka-u.ac.jp [★=@]

居室:H棟-721 豊中キャンパス

住所:〒560-0043 大阪府豊中市待兼山1-1