April 2021–March 2022

Kavli IPMUANNUAL REPORT 2021

CONTENTS
FOREWORD

2

1 STATISTICS

4

2 NEWS & EVENTS

8

3 ORGANIZATION

10

4 STAFF

14

5 RESEARCH HIGHLIGHTS

20

5.1 Impact of the COVID-19 Pandemic on Astronomy in the First Two Years ������������������������������������������������������������������ 20
5.2 Towards the Post-COVID CMB Activity in Kavli IPMU ������������������������������������������������������������������������������������������������������������ 22
5.3 Confluence in Quantum K-Theory ������������������������������������������������������������������������������������������������������������������������������������������������ 24
5.4 Solving Chiral Gauge Theories �������������������������������������������������������������������������������������������������������������������������������������������������������� 26
5.5 Commissioning of Prime Focus Spectrograph (PFS) on the Subaru Telescope:		

The Last Spurt of Its Development Has Started �������������������������������������������������������������������������������������������������������������� 28

5.6 Identifying the Origin of Primordial Gravitational Waves ���������������������������������������������������������������������������������������������������� 31
5.7 Could Bizarre Lumps of Q-balls Leave Behind a Hint About How Matter Was Formed? �������������������������������������� 33
5.8 Exporing Theta-Vacua of Yang-Mills Theories �������������������������������������������������������������������������������������������������������������������������� 35
5.9 AI Ethics Score Research �������������������������������������������������������������������������������������������������������������������������������������������������������������������� 37

6. AWARDS & HONORS

40

7. CONFERENCES

42

8. CONFERENCE PRESENTATIONS AND SEMINAR TALKS43

9. OUTREACH AND PUBLIC RELATIONS

44

Copyright © 2020 Kavli IPMU
All rights reserved
Editors: Tomiyoshi Haruyama (Chair), Misao Sasaki, Junichi Kanzaki
Editing Staff: Shoko Ichikawa
Kavli Institute for the Physics and Mathematics of the Universe
UTIAS, The University of Tokyo
5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan
Tel: +81-4-7136-4940 Fax: +81-4-7136-4941
https://www.ipmu.jp/

April 2021–March 2022

Kavli IPMUANNUAL REPORT 2021

On the cover:This is the focal plane of Prime Focus Spectrograph (PFS) on the Subaru telescope
prime focus. Many small dots distributed in the hexagonal area are fiber positioners
called "Cobra" each of which is integrated with an optical fiber and a microlens thatreceives photons from the sky and feeds them to the spectrograph. There are about2400 of them in total, which can be moved individually and very accurately to thepositions around them where astronomical objects such as stars and galaxies ofinterest are imaged on the focal plane. Meanwhile, the six square devices around thehexagonal area are the CCD cameras to measure the positions of bright stars on theimages for the telescope auto guiding and field acquisition (Credits: PFS project).

Foreword

Foreword

It is a significant recognition of his achievements and stature in mathematics. I applaud him for taking on thisimportant responsibility and look forward to his leadership at IMU.
“M” of the Kavli IPMU stands for “mathematics.” We include mathematics in our name since we believe thatmathematics plays an essential role in our mission to solve fundamental questions about our Universe. Hiraku
exemplifies this mission. When I was a faculty member in Kyoto University and invited Edward Witten to Japan
in 1994, he wanted to meet Hiraku. It turned out that mathematical formulas Hiraku derived in 1993 played
an essential role in Witten’s work with Cumrun Vafa on quantum gauge theory in four dimensions, which was
published a couple of months after his meeting with Hiraku. Hiraku’s works over the last three decades have
had enormous impacts on physics as well as on mathematics. Among his many honors and recognitions, heis a recipient of the Cole Prize in Algebra from the American Mathematical Society and the Japan Academy
Prize. The fact that he has been chosen to lead IMU for the next four years validates the founding vision of the
Kavli IPMU that, by integrating mathematics with physics and astronomy, we make advances and open new
directions of research in mathematics as well as in physics and astronomy.
We are also making great progress in experiments and observations. Super-Kamiokande Gadolinium Project,initiated by our own Mark Vagins, is expecting the first physics results in 2023. Hyper-Kamiokande construction is on schedule, and its tunnel excavation has reached the center of the cavern dome. At Subaru Telescope,
Hyper Suprime-Cam survey completed its observation and will release cosmology parameters this year, andPrime Focus Spectrograph expects to complete all deliveries and test by 2023 and start its scientific observations in 2024. LiteBIRD, the satellite to detect CMB polarizations, is working on its mission definition review.

Hirosi Ooguri
DirectorBy the time you read this Annual Report, I hope the COVID-19 pandemic is in our rear view or at least
stays in a manageable level. In October, the Japanese government resumed visa waiver programs for
68 countries and regions Tuesday, lifting COVID-19-induced restrictions. At the Kavli IPMU, we haveresumed in-person seminar series, workshops, and conferences and are welcoming back visitors from abroad.
We are pleased to welcome Patrick de Perio, Elisa Ferreira, and Jia Liu as our new tenure-track faculty members. Patrick works on underground high energy experiments including T2K, Super-Kamiokande, and HyperKamiokande. Elisa works in the interface between cosmology, astrophysics, and high energy physics, withfocus on the dark sector of the Universe. Jia works on the large-scale structures to elucidate fundamental
physics, such as the nature of dark energy and neutrino mass, using cosmological observations of the cosmic
microwave background and galaxies together with state-of-the-art numerical simulations.

In my inaugural address as the Director of the Kavli IPMU in October 2018, I stated my commitment to provide
an inclusive and supportive environment to the diverse group of people in our community. Last year, welaunched the Kavli IPMU Diversity Initiative to make progress in diversity, equity, and inclusion. We established the Chien-Shiung Wu Prize Postdoctoral Fellowship for female scientists, with the approval of the son
and granddaughter of Chien-Shiung Wu, whose groundbreaking experiment proved that parity symmetry is
broken by the weak interaction. The inaugural recipient of the prize is Man-Wai Cheung, who is a mathematician working on cluster algebras, mirror symmetry for cluster varieties, and the relation between representation theory and mirror symmetry. We are also offering leadership trainings to our members with focus on
valuing diversity and leading inclusively, improving our communication on diversity issues to them, organizing outreach activities for female students in science, and offering childcare support for our conference participants. We are reviewing outcomes of these activities and striving to improve them.


Hirosi Ooguri

I am also pleased to report that Hiraku Nakajima, one of our professors in mathematics, is the next Presidentof the International Mathematical Union (IMU). IMU represents mathematical societies of more than 80 countries around the world, organize the International Congress of Mathematicians, and awards the Fields Medals.

2

Kavli IPMU Annual Report 2021

Kavli IPMU Annual Report 2021

3

1

StatisticS

Statistics

300

273

285

297 300 291

Total Number of Staff
329
320
311 318303

RESEARCH ACTIVITIES
2000

1,882

247

250

230

1,465

1500

202

200

1,114
158

150

165

100

80

50

63

21
18
0 3

10
7

194 209236

259 252 274 279 280 291 265
245 255

18
0
3
21

63
10
7
80

478
500

27
10

25
11

28
10

27
10

30
10

32
10

31
10

29
10

27
10

28
11

29
11

27
11

27
11

125 165 194 209 236 245 255 259 252 274 279 280 291 265
22 27 25 28 27 30 32 31 29 27 28 29 27 27
11 10 11 10 10 10 10 10 10 10 11 11 11 11
158 202 230 247 273 285 297 300 291 311 318 320 329 303

RESEARCHERS

Percentage of Overseas

300

250

44%
52%

200

56%
150

862

125

22
11

0

40% 41%

38%
98
79

105

35%

90

41% 49% 42%
41%

168
65
103

372
103
269

432
345

103
269
372

345
87
432

28%
17
50
28% 465
13
0Overseas
Domestic% of Overseas% of Female

4

65

46%

473

457

497

728
464

738
436

560

463

384

238

338

296

264

302

465

688

768

446

478 392384 238
862 630

497 544 471
338 473 457
835 1,017 928

505
296
801

464
264
728

436 560 463 777 1,114
302 465 446 688 768
738 1,025 909 1,465 1,882

300

45%
250

111 136 118 135 119
102

200

105
150

186
156

94

50

0

Oct. 2007 Mar. 2008 Mar. 2009 Mar. 2010 Mar. 2011 Mar. 2012 Mar. 2013 Mar. 2014 Mar. 2015 Mar. 2016 Mar. 2017 Mar. 2018 Mar. 2019 Mar. 2020 Mar. 2021 Mar. 2022

5
17 60 92 100 79 105 98 105 90 102 111 136 118 135 119
13 46 65 73 94 130 131 147 150 169 150 163 143 162 156 146
28% 28% 48% 56% 52% 38% 44% 40% 41% 35% 41% 41% 49% 42% 46% 45%
0% 2% 5% 6% 5% 2% 5% 5% 6% 4% 6% 8% 9% 10% 9.3% 11.7%

Kavli IPMU Annual Report 2021

471

SEMINARS & CONFERENCES

163 143 162 156 146
147 150 169 150
130 13173

544

Multiple visits in a given year are counted as one.
* Number of participants for online conferences are included from FY2020 onward.

100

60

630

801
505

392

87

92
100

835

777
909

FY 2007 FY 2008 FY 2009 FY 2010 FY 2011 FY 2012 FY 2013 FY 2014 FY 2015 FY 2016 FY 2017 FY 2018 FY 2019 FY 2020* FY 2021*

Visitors (Overseas) 65
Visitors (Domestic) 103
Visitors (Total)
168

100

48%

1,025

1,017 928

1000

Oct. 2007 Mar. 2008 Mar. 2009 Mar. 2010 Mar. 2011 Mar. 2012 Mar. 2013 Mar. 2014 Mar. 2015 Mar. 2016 Mar. 2017 Mar. 2018 Mar. 2019 Mar. 2020 Mar. 2021 Mar. 2022

Researchers
Research Support Staffs
Administrative staffs
Total

Statistics

STAFF

Seminars
Conferences

7

249

246

222
184

192

216

207

140

24
4

196

232

11

16

12

11

14

13

17

14

21

11

18

116

117

8

12

FY 2007 FY 2008 FY 2009 FY 2010 FY 2011 FY 2012 FY 2013 FY 2014 FY 2015 FY 2016 FY 2017 FY 2018 FY 2019 FY 2020 FY 2021

24
4

156
7

140
11

186
16

196
12

232
11

249
14

246
13

222
17

184
14

192
11

216
21

207 116
18
8

117
12

Kavli IPMU Annual Report 2021

5

Statistics

TOTAL EXPENDITURE
589

600
550

519

500

480

450

68

400
350

347

350

67

449

78

449

422

496

81

80

77

79

202

200

70
60

236

252

40

115

100

3000

2,707

80

30

150

3,372 3,425

3500

20
10

9

0

MEDIA COVERAGES AND OUTREACH ACTIVITIES
7,540

783
1,259

1500 1,366

896

25
25
288
0 132

48
112

911

425
92

538

489

96

90
444

453
93

397
91

387
82

653

574

619

117
88
404

231
80
234

486

486

825

906

987

1,027 1,101 1,023 1,006

295
104

635

948

2,827

730

2,513 523
391

335
119

268
98

494

411

265
18
553

268
25
647

408

388

500

2,864

925

1,310 1,357 1,286 1,364

BREAKDOWN OF FY 2021 TOTAL EXPENDITURE
7000

6,296*

6,232

6,084

1,225 1,301 1,024

1,410
1,524

2,991 3,041

Personnel
Project Activities
Travel Expenses
Equipment
Other Research Project

Publications
9
115 202 236 252 347 350 480 449 449 422 519 496 589 563% of international collaboration 49% 57% 68% 60% 67% 69% 67% 75% 78% 78% 81% 79% 80% 77%

7,018

1,842 1,866

FY 2007 FY 2008 FY 2009 FY 2010 FY 2011 FY 2012 FY 2013 FY 2014 FY 2015 FY 2016 FY 2017 FY 2018 FY 2019 FY 2020 FY 2021

CY 2007 CY 2008 CY 2009 CY 2010 CY 2011 CY 2012 CY 2013 CY 2014 CY 2015 CY 2016 CY 2017 CY 2018 CY 2019 CY 2020 CY 2021

1200

3,262

2,362 846

2000

1000

2,844

2,844

2500

50

250

0

69

78

90

49

300

50

60

57

67

75

563

(%)
100

(1,000,000 JPY)

3,910 3,902

Statistics

PUBLICATIONS

6000

1000

933

800

5,581

5,454

4,453* 4000

3,339 3,340

600

400

227

366
163

1,376
130
47 97
40
33
0 7 0

135
119
16

541

531

3,277

200

5000

4,764 382

4,545

379
157

551

167

170

153
29

137
30

143 161
27 34

203

316

318

392

439

174

220

218

219

173

195

182

523
18.5 %

304

222

143

3000

1,364
48.2 %

25
0.9 %
647
22.9 %

2000
1000

223

FY 2007 FY 2008 FY 2009 FY 2010 FY 2011 FY 2012 FY 2013 FY 2014 FY 2015 FY 2016 FY 2017 FY 2018 FY 2019 FY 2020 FY 2021

participants in outreach activities
media coverages (domestic)
media coverages (international)

268
9.5 %

0

(1,000,000 JPY)
Personnel
Project Activities
Travel Expenses
Equipment
Other Research Project* Number of participants of the Kashiwa Campus Open day is not included in FY2020 and FY2021.

6

Kavli IPMU Annual Report 2021

Kavli IPMU Annual Report 2021

7

APRIL>> The 24th ICRR & Kavli IPMU public lecture“The wonders of a universe full of matter” [online]>> Research institutes in Japan and France establish
new laboratory for astrophysics and particle physics>> COSMOS-Webb program to map earliest structureof the Universe selected by James Webb Space
Telescope>> PFS can now successfully observe night sky spectra>> Film screening “Secrets of the Surface:
The Mathematical Vision of Maryam Mirzakhani”[online]April 2021 - March 2022

JULY>> Director Hirosi Ooguri gives summary talk at Strings
2021>> Parliamentary Vice-Minister of MEXT Hidehiro
Mitani visits Kavli IPMU>> Director Hirosi Ooguri elected Chair of the Board ofTrustees of the Aspen Center for Physics>> Leading xenon researchers unite to build nextgeneration Dark Matter Detector>> Split second behavior of muons in atoms uncovered
for first time>> Number Theory, Strings and Quantum Physics [online]>> Hyper-Kamiokande Collaboration Meeting [online]>> Quarkonia Meet Dark Matter [online]>> Fundamentalz Bazaar>> Axions could be the fossil of the Universe
researchers have been waiting for>> A rogue in the “Cosmic Standard Candle”?
- the relic of the densest white dwarf has been
detected in the remnant of its supernova >> Science Cafe “Universe” [online]>> Research into “Birth of Elements” awarded grant by
the Leverhulme Trust>> Theoretical proof that a strong force can create
light-weight subatomic particles>> A new type of supernova illuminates an old mystery

8

Kavli IPMU Annual Report 2021>> Masashi Hazumi to become director of new
research institute studying the universe and its
particles>> Open Campus Kashiwa 2021 (Kavli IPMU: Oct 23- 24) [online]

NOVEMBER
AUGUSTJUNE

OCTOBER>> President of the Republic of Armenia Armen
Sarkissian visits Kavli IPMU>> Astrophysicists, social scientists to probe theUniverse’s deepest mysteries>> Hirosi Ooguri named Benjamin Lee Professor>> Focus Week on Quantum Mechanical Systems at
Large Quantum Number [online]>> 6th “Actually I Really Love Physics!”–Career Paths ofFemale Physics Graduates [online]>> Particle Acceleration in Solar Flares and the Plasma
Universe --Deciphering Its Features Under Magnetic
Reconnection-- [online]>> The World of Mathematical Physics II [online]>> Kavli IPMU x ICRR Joint Public Lecture: “A dream ofmodern mathematics. A cutting edge of physics”[online]News & Events

2

NEWS & EVENTSNews & Events

JANUARY>> New Observational Windows on the High-Scale
Origin of Matter-Antimatter Asymmetry [online]>> Measuring trust in AI>> New theory finds upcoming satellite mission will beable to detect more than expected>> Researchers uncover model for extremely luminousand fast rising supernova>> Scientists make a new type of optical device usingalumina>> Hitoshi Murayama named new AAAS fellow>> 7th Kavli IPMU/ELSI/IRCN Joint Public Lecture:“A Question of Origins” [online]

FEBRUARY>> Hyper-Kamiokande Collaboration Meeting

DECEMBERSEPTEMBER>> Young-Kee Kim elected Vice President of theAmerican Physical Society>> Science Cafe “Universe” [online]>> Dark Sectors of Astroparticle Physics(AstroDark-2021): Axions, Neutrinos, Black Holesand Gravitational Waves [online]>> Record-breaking simulations of large-scale structureformation in the Universe>> Gravitational waves could be key to answering why
more matter was left over after Big Bang>> Researchers capture fastest optical flash emitted
from a newborn supernova>> Eiichiro Komatsu awarded the Inoue Prize for Science>> Unveiling substructures at the edge of the Galaxy>> Kavli IPMU Annual Report 2020 released>> 10th Annual WPI Science Symposium: “To The Future
NanoWorld” [online]

MARCH>> Fundamentalz Festival mini: An Exhibition of workby Artists and Researchers>> Cosmic Cartography 2022: Exploring the Cosmic
Web and Large-Scale Structure [online]>> PFS 13th Collaboration Meeting [online]>> What Is Dark Matter? - Comprehensive Study of the
Huge Discovery Space in Dark Matter - [online]

Kavli IPMU Annual Report 2021

9

Kavli IPMU

Kavli IPMU Management

President
Teruo Fujii

UTIAS

Director

Director: Hiroaki Aihara

Kavli IPMU External
Advisory Committee

Hirosi Ooguri

Administrative
Director

Deputy Directors

Tomiyoshi Haruyama

Assistant Administrative
Director

Hiroaki Aihara
Misao Sasaki
Tomiyoshi Haruyama

Junichi Kanzaki

Steering Committee

The Kavli IPMU has a rather unique organization. While
research is conducted in a flat-structure manner with loosely
defined grouping, the decision making is done in a top-down
scheme under the Director’s strong leadership. This scheme
minimizes the administrative load for the researchers. It is also
intended to maximally extract young researcher’s creativeand challenging minds as well as to encourage daily crossdisciplinary interactions.
The Director is appointed by the President of the University ofTokyo and reports directly to his office. The Director proposes
to hire the Principal Investigators to the President. For otherhiring of research staff and administrative staff, he has a complete authority. He is also solely responsible for making allother decisions. He is assisted by the three Deputy Directors
and the Administrative Director. They constitute the Executive Board (EB) and regularly meet to ensure smooth operation of the Institute. The EB has direct access to the Office of
the President for consultations on both scientific and administrative matters.

The Director is obliged to report the appointments of new
Principal Investigators and faculty members to the Director of
the University of Tokyo Institutes for Advanced Study (UTIAS).
Also, to clear the university formality in faculty hiring, the decisions of the Institute have to be endorsed by the Steering
Committee of the Kavli IPMU.
The Principal Investigators are world’s leading scientists intheir fields. They have a large autonomy in the research they
conduct. They can make proposals to the Director to hire
research staff at the Institute.

Organization

3

ORGANIZATION

Organization

The External Advisory Committee (EAC), appointed by the
President of the University of Tokyo, reviews annually the scientific achievement and activities of the Institute and advises
the President on scientific priorities and the research activities
to keep the Institute stay on the course of its objectives.

Executive Board
Chair

Hirosi Ooguri
Hiroaki Aihara
Misao Sasaki
Tomiyoshi Haruyama
		Mikhail Kapranov
Masahiro Takada
Mark Vagins
Hiromi Yokoyama

Director
Deputy Director
Deputy Director
Administrative Director/Deputy Director
Principal Investigator
Principal Investigator
Principal Investigator
Professor

The External Advisory Committee Members (March 2021)
John Ellis
Giovanni Felder
Joshua Frieman
Masahiko Hayashi
Tatsuya Nakada
Yongbin Ruan
Sakura Schafer-Nameki
Nigel Smith

King’s College London
ETH Zürich
FNAL/U Chicago; Chair
JSPS Bonn Office
EPFL
Zhejiang University
U Oxford
SNOLAB

Particle Theory
Mathematics
Astrophysics
AstronomyHigh Energy Experiment
Mathematics
Mathematical Physics
Astroparticle Physics

Kavli IPMU Research

Principal Investigators
Faculty, Postdocs, Students, Visitors

10

Kavli IPMU Annual Report 2021

Kavli IPMU Annual Report 2021

11

Organization

experiments conducted at the Kamioka underground laboratory. The Berkeley Satellite, besides being a place forresearch, serves as a contact place to the US scientific community. We also have close collaborative relations with several institutions both in Japan and overseas as well as withother departments within the University of Tokyo.

The Kavli IPMU holds close relations with similar research
institutions in the world for encouraging exchanges in
research and training of young research staff. We have signed
either an agreement or a memorandum of understanding
with those institutions.

Foreign institutions/consortia/programs having MOU with the Kavli IPMU

Host InstituteCollaborating Institutions(The Univ. of Tokyo)(domestic)

National Astronomical
Observatory in Japan Department of Mathematics
 Institute for Cosmic Ray Research(Kashiwa, Kamioka) Department of Physics
 Department of Astronomy

Collaborating Institutions(overseas)

Department of Physics,
University of California, Berkeley, USA
Department of Astrophysical Sciences,
Princeton University, USA
Institut des Hautes
Etudes Scientifiques (IHES), France

12

Kavli IPMU Annual Report 2021

Kavli IPMU
Kashiwa Campus
Kamioka Branch

Berkeley
Satellite

Department of Physics,
Kyoto University
High Energy Accelerator
Research Organization (KEK)
Yukawa Institute for
Theoretical Physics,
Kyoto University

The University of California, Berkeley, Department of Physics
National Taiwan University, Leung Center for Cosmology and Particle Astrophysics (LeCosPA)
The Astrophysics Research Consortium [on the Sloan Digital Sky Survey III ]The Astrophysics Research Consortium [on the Sloan Digital Sky Survey AS3 (“After SDSS III”)]
The Astrophysics Research Consortium [on the Sloan Digital Sky Survey IV ]Garching/Munich Cluster of Excellence on “The Origin and Structure of the Universe”
UNIFY (Unification of Fundamental Forces and Applications) [under the EU’s Seventh Framework Program]
The Scuola Internationale Superiore di Studi Avanzati (SISSA)The Academia Sinica Institute of Astronomy and Astrophysics of Taiwan (ASIAA) [on the SuMIRe Project]
The Intermediate Palomar Transient Factory (iPTF)
Steklov Mathematical Institute, Russian Academy of Sciences
Center for Mathematical Sciences, Tsinghua University
The Tata Institute of Fundamental Research
TRIUMF (Canada’s National Laboratory for Particle and Nuclear Physics)
Deutsches Elektronen Synchrotron (DESY)
Princeton University
The University of Oxford, Department of Physics
The Kavli Institute for Astronomy and Astrophysics at Peking University (KIAA)
Le Centre National de la Recherche Scientifique (CNRS)The Mainz Institute for Theoretical Physics (MITP)
Johns Hopkins University
The University of Bonn

Organization

The main laboratory building on the Kashiwa Campus provides a basis for our researchers. Even most of experimentalists who are involved in Kamioka experiments and astronomical observations spend a good fraction of their time in
Kashiwa for analyzing data, sharing seminars and discussing
with theorists. The Kamioka Branch is a basis for the Kavli
IPMU staff members who are engaging in the undergroundResearch Center for
Neutrino Science,
Tohoku University
Institiute of Physical andChemical Research (RIKEN)
Institiute of Statistical
Mathematics (ISM)

Kavli IPMU Annual Report 2021

13

4

STAFF

Director
Hirosi Ooguri, Mathematical Physics

Deputy Directors
Hiroaki Aihara, High Energy Physics
Tomiyoshi Haruyama, High Energy Physics
Misao Sasaki, Cosmology

Principal Investigators
Hiroaki Aihara(U Tokyo), High Energy Physics
Alexey Bondal(Steklov Math. Inst.), Mathematics
Kentaro Hori, String Theory
Kunio Inoue(Tohoku U), Neutrino Physics
Takaaki Kajita(U Tokyo, ICRR), Neutrino Physics
Mikhail Kapranov, Mathematics
Stavros Katsanevas(European Gravitational Observatory),
Experimental Physics

14

Kavli IPMU Annual Report 2021

Staff

Faculty Members

Masahiro Kawasaki(U Tokyo, ICRR), Cosmology
Young-Kee Kim(U Chicago), High Energy Physics
Toshiyuki Kobayashi(U Tokyo, Math Sci), Mathematics
Toshitake Kohno(Meiji U), Mathematics
Eiichiro Komatsu(MPI for Astrophysics), Cosmology
Kai Uwe Martens, Experimental Physics
Shigeki Matsumoto, Cosmology
Shigetaka Moriyama(U Tokyo, ICRR), Neutrino Physics
Hitoshi Murayama(UC Berkeley), Particle Theory
Masayuki Nakahata(U Tokyo, ICRR), Astroparticle Physics
Hiraku Nakajima, Mathematics
Mihoko Nojiri(KEK), Particle Theory
Yasunori Nomura(UC Berkeley), Particle Theory
Hirosi Ooguri(CALTECH), Mathematical Physics
David Spergel(Princeton U), Cosmology
Naoshi Sugiyama(Nagoya U), Cosmology
Masahiro Takada, Cosmology

Tomoyuki Abe, Mathematics
Hiroaki Aihara(U Tokyo), High Energy Physics
Alexey Bondal(Steklov Math. Inst.), Mathematics (2021/8/12022/2/15)
Elisa Gouvea Mauricio Ferreira, Cosmology (from 2021/12/3)
Mark Patrick Hartz, Neutrino Physics
Tomiyoshi Haruyama, High Energy Physics
Simeon John Hellerman, String Theory
Takeo Higuchi, High Energy Physics
Chiaki Hikage, Cosmology
Kentaro Hori, String Theory
Shunsaku Horiuchi, Theoretical Physics (from 2021/8/10)
Yukari Ito, Mathematics
Mikhail Kapranov, Mathematics
Nobuhiko Katayama, High Energy Physics
Khee-Gan Lee, Astronomy
Jia Liu, Cosmology (from 2021/9/1)
Kai Uwe Martens, Experimental Physics
Shigeki Matsumoto, Cosmology
Tomotake Matsumura, Experimental Physics
Thomas Edward Melia, Theoretical Physics
Todor Eliseev Milanov, Mathematics
Hitoshi Murayama(UC Berkeley), Particle Theory
Hiraku Nakajima, Mathematics
Toshiya Namikawa, Cosmology (from 2021/8/1)
Andrei Okounkov(Columbia U), Mathematics (from2021/9/1)
Hirosi Ooguri(CALTECH), Mathematical Physics
Tadashi Orita, Experimental Physics
Misao Sasaki, Cosmology
Satoshi Shirai, Particle Theory
John David Silverman, Astronomy
Yevgeny Stadnik, Theoretical Physics (till 2021/12/31)
Nao Suzuki, Astrophysics (till 2021/9/15)
Yuji Tachikawa, Particle Theory
Masahiro Takada, Cosmology
Tadayuki Takahashi, Experimental Physics
Shinichiro Takeda, Experimental Physics
Naoyuki Tamura, Astronomy
Yukinobu Toda, Mathematics
Mark Robert Vagins, Astroparticle Physics
Taizan Watari, Theoretical Physics
Atsushi Yagishita, Experimental Physics
Masaki Yamashita, Astrophysics
Masahito Yamazaki, String Theory
Naoki Yasuda, Astronomy
Hiromi Yokoyama, Science and Society
Naoki Yoshida(U Tokyo), Astrophysics

Project Researchers
Shunsuke Adachi, Experimental Physics (till 2021/9/30)
Meer Ashwinkumar, String Theory
Metin Ata, Cosmology
Tobias Binder, Theoretical Physics
Connor Hugh Bottrell, Astrophysics
Philip Ewen Boyle Smith, Theoretical Physics (from2021/9/16)
Tuan Khai Bui, Experimental Physics
Yalong Cao, Mathematics (till 2021/7/15)
Anqi Chen, Cosmology (from 2021/11/1)
Thomas Rafael Czank, Experimental Physics (till 2021/11/30)
Anton Reyes De la Fuente, String Theory
Xuheng Ding, Astronomy
Zhiyuan Ding, Mathematics
Matthew Dodelson, String Theory (till 2021/9/30)
Joshua Armstrong Eby, Cosmology
Fatemeh Elahi, High Energy Physics (till 2021/5/10)
Dmitrii Galakhov, String Theory
Naoki Genra, Mathematics
Tommaso Ghigna, Experimental Physics
Ryuichiro Hada, Cosmology
Takashi Hasebe, High Energy Physics
Thuong Duc Hoang, Experimental Physics (from 2021/11/1)
Shunichi Horigome, Theoretical Physics (from 2021/6/1)
Seyed Morteza Hosseini, String Theory (till 2021/9/30)
Shuhei Iguro, Particle Theory (2021/4/1 -9/30)
Yuko Ikkatai, Science and Society (till 2021/9/30)
Derek Beattie Inman, Cosmology
Kazuhiro Ito, Mathematics (from 2021/12/2)
Jian Jiang, Astronomy
Kookhyun Kang, High Energy Physics (from 2021/8/16)
Miho Katsuragawa, Experimental Physics
Lalitwadee Kawinwanichakij, Astrophysics (till 2021/10/31)
Ilya Khrykin, Astrophysics
Yosuke Kobayashi, Cosmology (2021/4/1 - 8/31)
Takafumi Kokubu, Theoretical Physics (from 2021/10/1)
Robin Rinze Kooistra, Astronomy (till 2022/1/15)
Chiara La Licata, Experimental Physics (till 2022/1/15)
Yun-Tsung Lai, High Energy Physics
Hsueh-Yung Lin, Mathematics (till 2021/7/31)
Wentao Luo, Astrophysics (till 2021/5/16)
Oscar Macias, Astrophysics (till 2021/8/31)
Abhiram Mamandur Kidambi, Mathematical Physics
Mohammad Khaled Hashem Mardini, Astronomy (from2021/7/1)
Rieko Momose, Astronomy (from 2021/8/1)
Yuki Moritani, Astronomy (till 2021/8/31)
Shigenori Nakatsuka, Mathematics
Emily Margaret Nardoni, Theoretical Physics (from2021/10/1)
Hyunbae Park, Cosmology (till 2021/10/31)
Youngsoo Park, Cosmology
Samuel Charles Passaglia, Cosmology
Kavli IPMU Annual Report 2021

Staff

Tadayuki Takahashi, Experimental Physics
Yukinobu Toda, Mathematics
Mark Robert Vagins, Astroparticle Physics
Naoki Yoshida(U Tokyo), Astrophysics

15

Alexis Roquefeuil, Mathematics (till 2022/1/1)
Ipsita Saha, Particle Theory
Yuki Sakurai, Experimental Physics (till 2021/9/30)
Yuya Sakurai, Astrophysics
Jingjing Shi, Cosmology
Tomoko Suzuki, Astronomy (from 2021/10/1)
Volodymyr Takhistov, Theoretical Physics
Izumi Umeda, Medical Application of Gamma-ray Imaging
Valeri Vardanyan, Cosmology
John Welliaveetil, Mathematics (till 2021/5/31)
Graham Albert White, Particle Theory
Kenneth Christopher Wong, Astronomy (till 2021/6/30)
Kiyoto Yabe, Astronomy
Ryo Yamagishi, Mathematics
Lilan Yang, Astronomy (from 2021/11/4)
Hassen Yesuf, Astronomy
Wai Kit Yeung, Mathematics
Vicharit Yingcharoenrat, Cosmology (from 2021/11/1)
Yu Zhao, Mathematics (from 2021/7/3)
Yunqin Zheng, Theoretical Physics
Zijun Zhou, Mathematics

Joint Appointments
Mark Patrick Hartz(TRIUMF), Neutrino Physics
Masashi Hazumi(KEK), High Energy Physics
Hitoshi Murayama(UC Berkeley), Particle Theory
Hirosi Ooguri(CALTECH), Mathematical Physics
Naoki Yoshida(U Tokyo), Astrophysics

Affiliate Members
Kou Abe(U Tokyo, ICRR), Astroparticle Physics
Shin’ichiro Ando(U Amsterdam), Astroparticle Physics
Bruce Berger(LBL, Berkeley (LBNL)), Neutrino Physics
Melina Bersten(IALP CONICET-UNLP), Astronomy
Sergey Blinnikov(ITEP), Astronomy
Agnieszka Maria Bodzenta-Skibinska(U Warsaw),
Mathematics
Kevin Allen Bundy(UC Santa Cruz), Astronomy
Andrew Bunker(U Oxford), Astrophysics
Scott Huai-Lei Carnahan(U Tsukuba), Mathematics
Cheng-Wei Chiang(Natl Taiwan U), Particle Theory
Yuji Chinone(U Tokyo), Astronomy
Neal K Dalal(Perimeter Institute), Astrophysics
Patrick De Perio, Neutrino Physics (from 2021/6/25)
Patrick Decowski(U Amsterdam/GRAPPA), Neutrino Physics
Jason Detwiler(U Washington, Seattle), Neutrino Physics
Mamoru Doi(U Tokyo, IoA), Astronomy
Chris Done(Durham U), Astrophysics
William Ross Goodchild Donovan(Tsinghua U, Beijing),
Mathematics
Yuri Efremenko(U Tennessee), Neutrino Physics
Motoi Endo(KEK), Particle Theory
Sanshiro Enomoto(U Washington, Seattle), Neutrino Physics
Gaston Folatelli(IALP CONICET-UNLP), Astrophysics

16

Kavli IPMU Annual Report 2021

Andreu Font-Ribera(IFAE-Barcelona), Cosmology
Brian Fujikawa(LBL, Berkeley), Neutrino Physics
Masataka Fukugita(U Tokyo), Astrophysics
Shao-Feng Ge(Shanghai Jiao Tong U), Theoretical Physics
Paolo Gondolo(U Utah), Cosmology (from 2021/4/22)
Lawrence J Hall(UC Berkeley), Particle Theory
Koichi Hamaguchi(U Tokyo), Particle Theory
Jiaxin Han(Shanghai Jiao Tong U), Astronomy
Tilman Hartwig(U Tokyo), Astrophysics
Tetsuo Hatsuda(RIKEN), Nuclear Physics
Yoshinari Hayato(U Tokyo, ICRR), Neutrino Physics
Katsuki Hiraide(U Tokyo, ICRR), Astroparticle Physics
Raphael Hirschi(Keele U), Astronomy
Junji Hisano(Nagoya U), Particle Theory
Kenta Hotokezaka(U Tokyo, School of Science), Astrophysics
Masahiro Ibe(U Tokyo, ICRR), Particle Theory
Kei Ieki(U Tokyo, ICRR), Neutrino Physics (from 2021/11/1)
Hirokazu Ikeda(JAXA), Experimental Physics
Motoyasu Ikeda(U Tokyo, ICRR), High Energy Physics
Shiro Ikeda(ISM), Mathematics
Yuko Ikkatai(Kanazawa U), Science and Society(from 2021/10/1)
Yoshiyuki Inoue(Osaka U), Astrophysics
Miho N. Ishigaki(NAOJ, Hawaii), Astronomy
Ken’ichi Izawa(Tokushima U), Particle Theory
Nicholas Kaiser(Ecole normale superieure), Cosmology
Jun Kameda(U Tokyo, ICRR), Neutrino Physics
Yousuke Kanayama(RIKEN), Experimental Physics
Amanda Irene Karakas(Monash U), Astronomy
Kazumi Kashiyama(Tohoku U), Astronomy (from 2021/5/1)
Yosuke Kataoka(U Tokyo, ICRR), Neutrino Physics(from 2021/11/1)
Akishi Kato(U Tokyo, Math Sci), Mathematical Physics
Yasuyuki Kawahigashi(U Tokyo, Math Sci), Mathematics
Edward T. Kearns(Boston U), Neutrino Physics
Sergey Ketov(Tokyo Metropolitan U), Theoretical Physics
Yasuhiro Kishimoto(Tohoku U), Neutrino Physics
Ryuichiro Kitano(KEK), Particle Theory
Chiaki Kobayashi(CAR, U of Hertfordshire), Astronomy
Masayuki Koga(Tohoku U), Neutrino Physics
Kazunori Kohri(KEK), Cosmology
Satoshi Kondo(Middle East Technical U), Mathematics
Yusuke Koshio(Okayama U), Neutrino Physics
Akito Kusaka(U Tokyo), Experimental Physics
Alexander Kusenko(UCLA), Particle Theory
Tatsuki Kuwagaki(Kyoto U), Mathematics
Alexie, Solange Leauthaud Harnett(UC Santa Cruz),
Astrophysics
Shiu-Hang (Herman) Lee(Kyoto U), Astrophysics
Marco Limongi(INAF), Astrophysics
Kazuo Makishima(U Tokyo), High Energy Physics
Ryu Makiya(ASIAA), Astronomy
Brice Menard(Johns Hopkins U), Astrophysics
Makoto Minowa(U Tokyo), Experimental Physics

Makoto Miura(U Tokyo, ICRR), High Energy Physics
Hironao Miyatake(Nagoya U), High Energy Physics
Hiroshi Mizuma(RIKEN), Experimental Physics
Anupreeta Sadashiv More(IUCAA), Astronomy
Surhud Shrikant More(IUCAA), Astronomy
Yuki Moritani(NAOJ, Hawaii), Astronomy (from 2021/9/1)
Takeo Moroi(U Tokyo), Particle Theory
David Robert Morrison(UC Santa Barbara), Mathematics
Shinji Mukohyama(Kyoto U), Cosmology
Motohico Mulase(UC Davis), Mathematics
Dinakar Muthiah(U Glasgow), Mathematics
Kentaro Nagamine(Osaka U), Astrophysics
Yasuhiro Nakajima(U Tokyo, School of Science),
Neutrino Physics
Kenzo Nakamura(KEK), Neutrino Physics
Tsuyoshi Nakaya(Kyoto U), High Energy Physics
Kazunori Nakayama(Tohoku U), Cosmology
Shoei Nakayama(U Tokyo, ICRR), Neutrino Physics
Takahiro Nishimichi(Kyoto U), Cosmology
Ken’ichi Nomoto(U Tokyo), Astronomy
Hirokazu Odaka(U Tokyo), High Energy Astrophysics
Masamune Oguri(Chiba U), Cosmology
Shinnosuke Okawa(Osaka U), Mathematics
Kimihiro Okumura(U Tokyo, ICRR), Neutrino Physics
Teppei Okumura(Academia Sinica), Cosmology
Yoshiyuki Onuki(U Tokyo, ICEPP), High Energy Physics
Domenico Orlando(INFN), String Theory
Masaki Oshikawa(U Tokyo, ISSP), Theoretical Physics
Masami Ouchi(U Tokyo, ICRR), Astronomy
Serguey Todorov Petcov(SISSA), Particle Theory
Shi Pi(Chinese Academy of Sciences), Astrophysics
Jason Xavier Prochaska(UC Santa Cruz), Astronomy
Anna Puskas(U Queensland), Mathematics
Robert Michael Quimby(San Diego State U), Astronomy
Susanne Reffert(U Bern), String Theory
Jason Rhodes(NASA JPL/Caltech), Cosmology
Joshua Thomas Ruderman(New York U), Particle Theory
Wiphu Rujopakarn(Chulalongkorn U), Astronomy
Kyoji Saito(Kyoto U), Mathematics
Ryo Saito(Yamaguchi U), Astrophysics
Shun Saito(Missouri U of Science and Technology),
Cosmology
Yoshihisa Saito(Rikkyo U), Mathematics (from 2021/10/1)
Francesco Sala(U Pisa), Mathematics
Katsuhiko Sato(JSPS), Astroparticle Physics
Vadim Schechtman(U Toulouse III-Paul Sabatier),
Mathematics
Christian Schnell(SUNY, Stony Brook), Mathematics
Kate Scholberg(Duke U), Neutrino Physics
Hiroyuki Sekiya(U Tokyo, ICRR), Neutrino Physics
Masato Shiozawa(U Tokyo, ICRR), High Energy Physics
Gary Shiu(U Wisconsin, Madison), String Theory
Aurora Simionescu(SRON Netherlands Institute for Space
Research), Astrophysics

Michael Smy(UC Irvine), Neutrino Physics
Yevgeny Stadnik(U Sydney), Theoretical Physics(from 2022/1/1)
Samantha Lynn Stever(Okayama U), Astrophysics
James L. Stone(Boston U), High Energy Physics
Shigeki Sugimoto(Kyoto U), Theoretical Physics
Nao Suzuki(LBL, Berkeley (LBNL)), Astrophysics(from 2021/9/16)
Atsushi Takahashi(Osaka U), Mathematics
Fuminobu Takahashi(Tohoku U), Particle Theory
Tadashi Takayanagi(Kyoto U), String Theory
Atsushi Takeda(U Tokyo, ICRR), Astroparticle Physics
Yasuhiro Takemoto(U Tokyo, ICRR), Experimental Physics
Yasuo Takeuchi(Kobe U), Astroparticle Physics
Hidekazu Tanaka(U Tokyo, ICRR), Neutrino Physics
Masaomi Tanaka(Tohoku U), Astronomy
Atsushi Taruya(Kyoto U), Astrophysics
Nozomu Tominaga(NAOJ), Astrophysics
Werner Tornow(Duke U), Neutrino Physics
Akihiro Tsuchiya(Nagoya U), Mathematics
Sachiko Tsuruta(Montana State U), Astrophysics
Edwin L Turner(Princeton U), Astrophysics
Kazushi Ueda(U Tokyo, Math Sci), Mathematics
Hokuto Uehara(Tokyo Metropolitan U), Mathematics
Alexander Voronov(U Minnesota), Mathematics
Christopher W. Walter(Duke U), Neutrino Physics
Shin Watanabe(JAXA), Experimental Physics
Bryan Webber(U Cambridge), Particle Theory
Roger Alexandre Wendell(Kyoto U), Neutrino Physics
Marcus Christian Werner(Duke Kunshan U), Mathematical
Physics
Benda Xu(Tsinghua U, Beijing), Experimental Physics
Tsutomu Yanagida(Shanghai Jiao Tong U), Particle Theory
Jun’ichi Yokoyama(U Tokyo, School of Science), Cosmology
Masashi Yokoyama(U Tokyo), High Energy Physics
Shuichiro Yokoyama(Nagoya U), Cosmology
Ying-li Zhang(Tongji U), Cosmology

Staff

Staff

Graduate Students
Yuto Arai, Mathematics
Weiguang Cao, Theoretical Physics
Laurence Cook(U Oxford), Neutrino Physics (till 2021/5/8)
Henrique De Campos Affonso, Mathematics
Sho Egusa, String Theory
Yuichi Enoki, Particle Theory
Linghu Fan, Mathematics
Saki Fujita, Experimental Physics (from 2021/10/1)
Kyosuke Higashida, Mathematics
Shunichi Horigome, Theoretical Physics (till 2021/5/31)
Yuxin Huang, Astronomy
Tomohiro Karube, Mathematics
Tenyo Kawamura, Experimental Physics
Tasuki Kinjo, Mathematics
Asahi Kojima, Particle Theory
Kavli IPMU Annual Report 2021

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StaffAdministration

Public Relations

Tomiyoshi Haruyama, Administrative Director, Project
Professor
Junichi Kanzaki, Assistant Administrative Director, ProjectLecturer
Isao Uehara, General Manager
Masayuki Tomita, Deputy General Manager

Motoko Kakubayashi
Marina Komori
Aya Tsuboi

Accounting
Shigeru Kobayashi* (till 2021/6/30)
Masataka Tanaka* (from 2021/7/1)
Naoko Ishida
Hiromi Yoshida
Yukiko Yoshikawa

Kamioka Branch
Fumitoshi Sakai*
Masako Ishikura
Yoshimi Kakioka
Hitoshi Nakagawa(*section head)

Budget Control
Daisuke Hamada*
Madoka Okamoto
Tomoko Shiga
Kaori Watanabe

Staff

Dan Kondo, Particle Theory
Toshiki Kurita, Theoretical Physics
Yasunori Lee, Particle Theory
Xiangchong Li(Carnegie Mellon U), Cosmology(till 2021/9/30)
Peijang Liu, Mathematics
Ryusei Maeda, Theoretical Physics
Tianle Mao, Mathematics
Takuro Matsumoto, Mathematics
Takahiro Minami, Experimental Physics
Kai Murai, Particle Theory
Colm Murphy, High Energy Physics (till 2021/9/30)
Shunsaku Nagasawa, Experimental Physics
Kanade Nishikawa, Particle Theory
Masaki Okada, Theoretical Physics
Fumiaki Otani, Experimental Physics
Tian Qiu, Cosmology
Yotaro Sato, Theoretical Physics
Yusuke Sato, Mathematics
Yuta Sato, Particle Theory
Tomoyuki Shimasaki, Experimental Physics
Ryota Shimoda, Theoretical Physics
Yusuke Suetake, String Theory
Sunao Sugiyama, Theoretical Physics
Shenli Tang, Astronomy
Takanori Taniguchi, Cosmology
Ryo Terasawa, Cosmology
Akira Tokiwa, Cosmology
Yutaka Tsuzuki, Experimental Physics
Yu Watanabe, Particle Theory
Yuki Watanabe, Cosmology
Xia Xiaokun, Mathematics
Goro Yabu, Experimental Physics
Chenghan Zha, Mathematics

Contract & General Purchasing
Kenji Irie* (till 2021/6/30)
Noboru Abe* (from 2021/7/1)
Yuri Kazama
Takako Okawa
Sachiko Shimada
Tomoko Yamanaka

General Management

Berkley satellite Members

Manabu Hirano*
Yuuko Enomoto
Mika Miura
Ayako Nakada
Mana Shindo
Rieko Tamura

Lawrence J Hall(UC Berkeley), Particle Theory
Yasunori Nomura(UC Berkeley), Particle Theory

International Relations and Researchers Support
Yuko Fukuda*
Rie Kohama
Masami Nishikawa
Hinaka Ochiai
Eri Shinoda

Network & Web Service
Satoko Inoshita
Masahiro Kawada

Planning & Assessment
Shoko Ichikawa

18

Kavli IPMU Annual Report 2021

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5

RESEARCH HIGHLIGHTS

Research Highlights

5.1 Impact of the COVID-19 Pandemic on
Astronomy in the First Two Years
Jia Liu

I arrived at Kavli IPMU during the COVID-19 pandemic. As a new mother and an early career scientist, my life has been heavily affected by the pandemic –– lost childcare, dropped productivity, disconnection from my colleagues, and a tough job
market. Thanks to the strong support I received from IPMU, I was able to settle in a new country smoothly. While rebuilding
my research and life routines, I couldn’t stop wondering: how are others in my field affected by the pandemic? Am I alone?

We found a surprising trend that the overall output of the field, measured by the yearly paper count, has increased.
While one may assume that COVID has mostly negative impacts on the world, this positive phenomenon may not be hardto understand: COVID-induced changes such as increased flexibility in work arrangement, reduced commutes and business trips, as well as improved virtual technologies, among others, are potentially favorable for conducting scientificresearch.
However, the increase in overall output in the field could be due to two factors: (1) an increase in new researchers and/or (2)an increase in individual productivity. As we investigated further, we found that (2) is mainly responsible for the trend. When
we counted the average number of papers each researcher produced, we saw boosted individual productivity seen
across most countries. Meanwhile, a decreasing number of incoming new researchers is seen in most of the countries we studied. This result indicates larger barriers for new researchers to enter the field, or for junior researchers to complete their very first project during COVID.
Sadly, the overall improvement in productivity seen in the field is not equally shared by female astronomers. A
smaller fraction of papers are written by women and fewer women are among incoming new researchers as compared to
pre-pandemic trends, in 14 out of 25 countries we studied. Even though female astronomers also became more productive
during COVID, the level of improvement is smaller than for men. Pre-COVID, female astronomers in countries such as the
Netherlands, Australia, and Switzerland were equally as or even more productive than their male colleagues, demonstrating that female researchers are indeed as productive as men when provided with adequate support. During COVID, on
average, no single country's female astronomers were able to be more productive than their male colleagues.

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Research Highlights

My colleague and friend Vanessa Böhm, who was a postdoc at UC Berkeley at the same time as me, had the same question.
We did some literature search, but weren’t satisfied with the limited studies we found, so we decided to answer this question by ourselves. We started meeting on Tuesday mornings (Monday afternoons for Vanessa). As computational cosmologists, we used the tools that we are trained well with –– data mining. We downloaded all the astronomical publications since1950, more than 1.2 million records from the SAO/NASA Astrophysics Data System, and analyzed the publication patternby gender and by country. Of course, gender and citizenship are confidential information that we can’t access. Instead, weassigned a gender probability to each author based on their given name and assigned a country based on their affiliation(s)listed in the paper. We searched for new trends during COVID that were not seen historically.

Our results are released in Böhm & Liu 2022 [1] and can be summarized by the figure above, which shows the impact of
COVID-19 on astronomy by country measured in 4 statistics (white columns), each paired with a corresponding genderdisparity measurement (the adjacent gray column to the right). Gray points are pre-COVID and red (green) points are during
COVID that are worse (better) than pre-COVID. The World statistics are shown in the first row. (1) Overall output (Cols. 1 &2): Ratio of the number of papers per year during COVID to pre-COVID, and corresponding fraction of female authors. (2)New researchers (Cols. 3 & 4): Ratio of the number of new authors per year during COVID to pre-COVID, and corresponding fraction of new female authors. (3) Individual productivity (Cols. 5 & 6): Weighted average number of papers perweighted, where none-first author papers are down-weighted, and the corresponding ratio of that between
active author Npaper
female to male authors. (4) Individual productivity irrespective of author position (Cols. 7 & 8): Unweighted averageunweighted, where the author order is ignored, and the corresponding ratio of that
number of papers per active author Npaper
between female to male authors.
Finally, we have only data from a limited period of time after the onset of the pandemic, while its impact is expected to belong-term. While we are able to study the quantitative outputs of the field during COVID, the quality of these papers is yet
to be seen. It would be valuable to revisit this topic in a few years.
Reference[1] V. Böhm and J. Liu, “Impact of COVID-19 on Astronomy: Two Years In”, arXiv:2203.15621 [astro-ph.IM].

Kavli IPMU Annual Report 2021

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Research Highlights

5.2 Towards the Post-COVID CMB Activity in
Kavli IPMU
Tomotake Matsumura
My previous contribution to this annual report was in 2018. Since then, COVID has brought a completely different lifestyle
to all, and the research activity related to CMB experiments at Kavli IPMU is no exception. Kavli IPMU CMB group members
work on ongoing and upcoming CMB experiments, including LiteBIRD, Simons Observatory, POLARBEAR/SimonsArray,
and CMB-S4. Unfortunately, during the COVID, we have limited lab access, no traveling, including going to the telescopesite at Atacama, Chile, and no participation in any domestic or international in-person conference. These gave us a tremendous impact on research and education. However, we have now started to see the end of it (hopefully), and I will describe
the progress related to the CMB experiences in FY2021.

Fig. 1: Images of one side of the fabricated filter. The other side is identical. (a) A photograph of the entire filter. The ruler is graduated up
to a length of 300 mm. (b) An enlarged area. (c) Rendering of confocal microscopy scanning of the SWS. (Credit: Takaku et al.)Research Highlights

For LiteBIRD, Kavli IPMU is in charge of developing the low-frequency telescope polarization modulator unit (PMU) and thedata analysis. After LiteBIRD was selected as the second ISAS/JAXA Strategic Large-class mission in May 2019, we focusedon developing the key technological challenges. We constructed the second-generation breadboard model of the PMU
system led by the former IPMU postdoc, Y. Sakurai (now an assistant professor at Okayama Univ.). The test campaign is now
led by the two postdocs, T. Hasebe and T. D. Hoang. The former IPMU postdoc, T. Ghigna (now a postdoc at QUP/KEK),
characterized a superconducting detector with an external magnetic field. These are important milestones for the LiteBIRD
development at this phase, and these activities resulted in the publishing of more than eight refereed papers in 2021-2022.
One of the by-products of the LiteBIRD PMU development is the work led by the graduate student at the Univ. of Tokyo, R.
Takaku; fabricating the laser machined moth-eye anti-reflection sub-wavelength structure on an infrared absorbing filter
made of alumina (see Fig. 1). A moth-eye is known to have an array of tiny structures smaller than the wavelength, whichfunctions as an anti-reflection layer to the incident radiation to its eye. We employ this moth-eye structure in our millimeterwave optical component for CMB and astrophysical observations. We provide this successfully fabricated filter to the
MUSTANG2 receiver on the Greenbank telescope as the world’s first implementation of the laser-fabricated filter used in
astronomical observation [1]. The preparation of the satellite project takes a long time (the currently scheduled LiteBIRD
launch is in the late 2020s). However, the successful development of LiteBIRD now directly contributes to the ongoing
astronomical observations in parallel.
Another highlight is providing the forebaffle for Simons Observatory (SO) Small Aperture Telescope (SAT). This is one of thetelescope structures which will be integrated into SO-SAT in Atacama, Chile, and will prevent stray light to the telescopefrom the surroundings. The former IPMU postdoc, F. Matsuda (now an assistant professor at ISAS/JAXA), designed it, andwe shipped it to Chile after being assembled on the Kashiwa campus. (see Fig. 2). Unfortunately, the time of the shipment
coincided with the shortage of containers in international shipping during COVID and the corresponding increase in the
shipping cost. Despite the challenges, tremendous administrative staff support in IPMU made it overcome this challenge,
and we shipped the forebaffle in time successfully.
By looking into the future, LiteBIRD will continue to move forward with a solid international partnership. SO is expected tostart observations in 2023. Last but not least, we now have new faculties, T. Namikawa, J. Liu, and E. Ferreira, who haveexpertise in theory, simulation, and data analysis. It is an exciting time, and we expect more integrated work among the
instrumentation-based efforts, simulation, data analysis, and cosmology in the coming years.
Reference[1] R . Takaku et al., “Large diameter millimeter-wave low-pass filter made of alumina with laser ablated anti-reflection coating,” Opt. Express 29, 41745-41765 (2021), see also https://www.ipmu.jp/en/20220127-MUSTANG2

Fig. 2: The forebaffle for the Simons Observatory Small Aperture Telescope carried by the IPMU CMB group member.

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Research Highlights

5.3 Confluence in Quantum K-Theory
Todor Eliseev Milanov
question to find an interpretation of J(q,Q) in terms of mirror symmetry. In a joint work with Alexis Roquefeuil [3], under theassumption that c1(X) ≥ 0, we proved that if we rescale the variables Qi and the components of J(q,Q) by appropriate powersof q − 1, then the resulting function has a limit q → 1 which coincides with the cohomological small J-function of X. Havingin mind the interpretation of the cohomological small J-function in terms of period integrals, it is very tempting to conjecture that there is a general method for constructing q-deformations of the period integrals in the theory of deformations ofcomplex structures.
References[1] A. Givental, On the WDVV equation in quantum K-theory. Michigan Math. J. 48(2000), 295–304[2] A. Givental and V. Tonita, The Hirzebruch-Riemann-Roch theorem in true genus-0 quantum K-theory, In: Symplectic,
Poisson, and noncommutative geometry, Math. Sci. Res. Inst. Publ., vol. 62, Cambridge Univ. Press, New York (2014),
43–91[3] T. Milanov and A. Roquefeuil, Confluence in quantum K-theory of weak Fano manifolds and q-oscillatory integrals fortoric manifolds, arXiv:2108.08620[4] E. Witten, Two-dimensional gravity and intersection theory on moduli space, Surveys in Diff. Geom. 1 (1991), 243–310

Research Highlights

Gromov–Witten (GW) theory was introduced by Witten in [4] in order to give a mathematical definition of the correlation
functions in a certain two-dimensional Quantum Field Theory (QFT) model. In particular, for every smooth projective variety X, the correlation functions give a set of symplectic invariants of X known as the GW invariants of X. In certain cases, if X
is a Calabi–Yau manifold, the GW invariants can be identified with the Taylor series expansion of an appropriate family of
period integrals that describe the deformations of complex structures of a certain complex manifold Y. The manifold Y iscalled the mirror model of X and usually there is an interesting duality between the complex geometry of Y and the symplectic geometry of X. Moreover, there is a proposal by Givental that every manifold X has a mirror model in the following sense:
Y is non-compact, one has to fix a holomorphic function f on Y, and a holomorphic volume form ω on Y and consider the
deformation theory of the triple (Y, f, ω). Respectively, the period integrals should be replaced with oscillatory integrals.
Shortly after Witten, Givental proposed a K-theoretic version of GW theory. It is expected that by using Kawasaki’s orbifold
generalization of the Hirzebruch–Riemann–Roch formula, one can express the K-theoretic invariants in terms of thecohomological ones. However, the relation is very complicated and so far it is known only in genus 0 (see [2]). It is a very
interesting problem to find the characterization of the K-theoretic GW invariants of X in terms of the mirror model (Y, f, ω) of
X. The main motivation for our work with Alexis Roquefeuil [3] came from our attempt to understand the role of the
K-theoretic J-function in mirror symmetry. More precisely, the J-functions in both K-theoretic and cohomological GW theory of a toric manifold can be identified with certain oscillatory integrals. The K-theoretic oscillatory integral is a q-oscillatory integral in the sense of Jackson and it has a limit as q → 1 which is the oscillatory integral corresponding to the cohomological J-function. One of the main motivations for our work is to test whether the K-theoretic J-function has a limit as q → 1.
Our result is an indication that the mirror model (Y, f, ω), whenever it exists, should have a q-deformation.
Let X be a smooth projective variety. The Gromov–Witten (GW) invariants of X are by definition certain intersection numbers on the moduli spaces Mg,n(X, d) of stable maps f : C → X, where C is a nodal Riemann surface of fixed arithmetic genus
g, equipped with a fixed number n of marked points z1, . . . , zn, and the map f is required to have a fixed degree d = f*[C] ∈H2(X). More precisely, we have evaluation maps evi : Mg,n(X, d) → X defined by evaluating f at the marked points zi and tautological line bundles formed by the cotangent lines T zi* C. Pulling back cohomology classes from X and taking characteristicclasses of the tautological line bundles yields a huge supply of cohomology classes on Mg,n(X, d). Integrating such cohomology classes against the virtual fundamental cycle of the moduli space yields a set of numbers known as the GW invariantsof X. Using GW invariants, Givental introduced the so-called small J-function of X. It is a formal power series J(Q1, . . . ,Qr) in
certain variables Q1, . . . ,Qr, known as the Novikov variables. The number r here is the so-called Picard number of X which canbe characterized as follows: there exists a set of r curve classes in H2(X), such that, every other curve class d decomposes
druniquely as a linear combination with coefficients non-negative integers (d1, . . . , dr). The coefficient in front of Q d1
1 · · ·Q r in*
the small J-function is a vector in H (X) whose components are GW invariants defined via the moduli space M0,1(X, d). It is
expected that in fact the small J-function is a convergent power series, that is, it is an analytic function in Q1, . . . ,Qr. The small
J-function is a solution to a certain system of Ordinary Differential Equations (ODEs) known as the small quantum differential
equations of X. In many examples, the small quantum differential equations can be solved in terms of period integrals
associated to a family of analytic hypersurfaces. If this happens, then the parameters Q1, . . . ,Qr can be interpreted as coordinates on a certain moduli space of complex structures and we usually say that the family of hypersurfaces is a mirror modelof X.
The K-theoretic version of GW theory was proposed by Givental in [1]. Pulling back K-theoretic vector bundles from K0(X)and taking the K-theoretic classes of the tautological line bundles Li yields a huge supply of K-theoretic vector bundles on
Mg,n(X, d). The K-theoretic GW invariants of X are defined as the Euler characteristic (K-theoretic pushforward to a point) of
K-theoretic vector bundles on Mg,n(X, d). Similarly, we can introduce the K-theoretic small J-function J(q,Q) as a generating
function of K-theoretic GW invariants defined by the moduli spaces M0,1(X, d). However, in addition to the variables Q1, . . . ,Qr
we have to introduce also an extra variable q for the following reason. In the cohomological case, the invariants are definedby integrating ev1* (ϕ) ψk where ψ is the 1st Chern class of L1. The power k is uniquely determined from the degree d because
the degree of the cohomology class must be equal to the dimension of the virtual fundmental cycle. In the K-theoretic casehowever, we have to compute the Euler characteristic of ev1* (Φ)Lk1 and since there is no dimension constraints, the number
k could be chosen arbitrary. The variable q is introduced in order to keep track of the powers of L1. It can be proved (see [2])that the K-theoretic small J-function J(q,Q) is a solution to a system of q-difference equations. It is a very interesting open

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Research Highlights

5.4 Solving Chiral Gauge Theories
Hitoshi Murayama

When it was discovered that another force in nature called the weak force fundamentally distinguishes left from right, itcame as a huge shock to physicists. The famous experiment conducted by Chien-Shiung Wu, whom we at Kavli IPMU
named our recent fellowship for distinguished female scientists after, studied the beta decay of 60Co nuclei. When she fixed
the direction of the spin of 60Co by a clever technique and observed which way an electron comes out, it preferred the same
direction as the spin. But in the mirror, it would prefer the opposite direction. The world in the mirror is not the same as ours!
Later, we learned something even more dramatic. Elusive elementary particles called neutrinos come in only one variety.
All of them are left-handed, namely they spin counterclockwise. Right-handed neutrinos have never been observed.*

0.008
0.006
0.004
0.002
- 0.002

1

2

3

4

v

Figure: T he potential for the SO(10) theory with 3 matter fields in the 16 representation. When supersymmetry is exact,
the potential does not have a minimum and the theory runs away (blue). With a small supersymmetry breaking,it settles to the minimum where the SU(3) global symmetry is broken to its SO(3) subgroup (red). Taken from [4].

The Standard Model of particle physics, established experimentally in 2012 by the long-anticipated discovery of the Higgs
boson, is built on the principle that left and right are fundamentally different. Such a theory is called “chiral”, the term thatoriginates in the ancient Greek word for hand χείρ (kheir). Because the Standard Model is based on another principle calledgauge theory, it belongs to a general class called “chiral gauge theory.” The problem is that we never figured out what
exactly it does.

an abundance of massless composite fermions, but we found they seem to minimize such composite states as much as
they can.

Quantum Field Theory, which unifies two pillars of modern physics, special relativity and quantum mechanics, is notoriously difficult to study. Practical calculations produce infinities that do not make sense. Fortunately for many cases, we candefine theories on discretized space and time called lattice so that we can avoid the infinities. The theory is then completely well-defined and can be put on a supercomputer to work out its consequences. This approach has been especiallysuccessful for the strong nuclear force. But so far this approach has not been possible for chiral gauge theories such as the
weak force for many technical reasons.

Technically, we studied SU(Nc) gauge theories with the matter content in the anti-symmetric tensor and Nc–4 anti-fundamental representations. When Nc is even, the SU(Nc–4) global symmetry is broken to its Sp(Nc–4) subgroup and there is no
massless composite fermion. When Nc is odd, the SU(Nc–4) global symmetry is broken to its Sp(Nc–5)×U(1) subgroup andthere are Nc–5 massless composite fermions. In both cases, past conjectures suggested that there should be O(Nc2) of them.
Since our results are very concrete, it should be possible to see which conjecture is correct once chiral gauge theories are
simulated on supercomputers in the future. We found similar results in theories with a symmetric tensor [3].

For most purposes, the weak force is weak enough that we can resort to a technique called perturbation theory. However,in some cases, we would like to know what happens if the weak force were stronger. Also, in many attempts to unify theobserved forces into a single force called “grand unified theories,” we need to understand what chiral gauge theories do.
I’ve proposed to study this question using supersymmetry as a guide. Nathaniel Seiberg and his collaborators showed how
we can work out exact solutions to supersymmetric gauge theories. Yet the results did not appear to be anywhere close to
how the real world works. My proposal is to introduce a small breaking of supersymmetry that still allows for exact solutions
that do not rely on the weakness of the force. I could obtain many such solutions, and they appear to connect smoothly towhat we would expect in the real world without supersymmetry [1].

Of course, the exact solutions we could obtain are possible only when the size of supersymmetry breaking is small. To reachthe real-world situations, the size of supersymmetry breaking needs to be made large. If there is a phase transition between
the two limits, we do not gain any new insights by studying the solutions I proposed. There is no proof that two limits aresmoothly connected. I am working with my collaborators further to understand this question better.

In addition, I could also explain why the nuclei bind to enable the periodic table of elements. The protons and neutrons bindto form nuclei because there is a bound state called pion that is much lighter than proton and neutron, as originally proposed by Yukawa. It is light because of the spontaneous breakdown of chiral symmetry as pointed out by Nambu. My
method showed explicitly that this occurs because of a condensate of meson bound states on a piece of paper, which used
to be possible only with supercomputers.
The next step was to study chiral gauge theories. This proved much more difficult technically, but with the help of collaborators, Csaba Csàki and Ofri Telem, we could solve some of the simplest chiral gauge theories [2]. The result turned out tobe completely different from what people had conjectured back in 80s. It was suggested that chiral gauge theories lead to* The plot thickened after our former PI Takaaki Kajita discovered that neutrinos actually have mass. Because massive particle can stop, there
cannot be distinction between left and right, raising an important paradox. We do not know yet how these two facts can be reconciled.

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For a long time, physicists believed that there is no difference between left and right. If you drop a ball in front of a mirror,
what happens in the mirror looks completely normal. Yes, it is true that most of us are right-handed, and our heart is on theleft-side of the body. But we can easily imagine that on some other planets, intelligent life forms are left-handed with theirheart on the right side of their body. There is no essential difference between left and right. In fact, the laws of gravity,
electromagnetism, and the strong nuclear force are all completely indifferent between left and right.

More recently, I studied arguably the simplest chiral gauge theories based on the SO(10) gauge group with Nf matter fields
in the 16-dimensional spinor representation. According to Prof. Yoshio Kikukawa of the University of Tokyo, these theories
are likely the first ones to be simulated on supercomputers. Together with a student at Kavli IPMU, Dan Kondo, and anundergraduate student in Berkeley, Cameron Sylber, we came up with clear predictions about what happens to global
symmetries [4]. When Nf =1, there is no global symmetry. When Nf =2, the SU(2) global symmetry remains unbroken. WhenNf =3, the SU(3) global symmetry breaks to SO(3). In all cases, there are no massless composite fermions.
I do not know whether nature makes use of these fascinating theories. I can only hope she does, perhaps in the dark sectorof the Universe ;-)References[1] Hitoshi Murayama, “Some Exact Results in QCD-like Theories,” Phys. Rev. Lett. 126 (2021) 251601.
[2] Csaba Csàki, Hitoshi Murayama, and Ofri Telem, “Some exact results in chiral gauge theories,” Phys. Rev. D 104 (2021)
065018.
[3] Csaba Csàki, Hitoshi Murayama, and Ofri Telem, “More exact results on chiral gauge theories: The case of the symmetrictensor,” Phys. Rev. D 105 (2022) 045007.
[4] Dan Kondo, Hitoshi Murayama, and Cameron Sylber, “Dynamics of Simplest Chiral Gauge Theories,” arXiv:2209.09287.

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Research Highlights

Naoyuki Tamura
We at Kavli IPMU are working on the development of a major astronomical instrument for more than a decade now. It iscalled PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope. The biggest news in
FY2021 was clearly the start of engineering observation. Namely, we started receiving photons from the sky on the spectrograph detectors all the way through the Subaru telescope and the PFS hardware!
PFS is a very wide-field, massively multiplexed, and optical & near-infrared spectrograph, and Kavli IPMU is the leading
institute in both aspects of the instrument development and the planning of a 360-night observation campaign on the
Subaru telescope for cosmology, galaxy & AGN evolution, and Galactic archaeology sciences. Exploiting the Subaru’s prime
focus, 2394 reconfigurable fibers will be distributed in the 1.3 degree-diameter field of view. The spectrograph system has
been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously deliver spectra from 380nm to1260nm in one exposure. From the Subaru’s prime focus, the Hyper Suprime Cam (HSC) has been continuously deliveringsuperb imaging data over a large area of the sky. Conducting spectroscopic follow-up using PFS is crucial to complete alarge census of the universe. This is unique not only because it exploits the unique capabilities of the Subaru Telescope suchas the light-gathering power of the 8.2m primary mirror and the wide field of view on the prime focus, but also because HSC
and PFS enable deep imaging and spectroscopic surveys on the same patches of the sky using the same 8.2m telescope,so one can well understand various systematics in the data which is essential for robust understandings of statistical properties of the universe.
The instrumentation has been carried out by the international collaboration managed by the PFS Project Office hosted by
Kavli IPMU, with work packages for subsystem and subcomponent developments assigned to various institutes in the collaboration. During the last few years, we delivered several subsystems from the PFS institutes to the Subaru telescopeobservatory on the summit of Maunakea, and successfully commissioned them (see Table 1). The recent highlight is obviously Prime Focus Instrument (PFI). It is a very complex subsystem with 2394 reconfigurable fiber positioners “Cobras”
which are the key components to deliver fluxes from stars and galaxies to the PFS instrument. Having had Metrology
Camera System (MCS), the first spectrograph module (SM1) with visible cameras, and the first on-telescope fiber cable(Cable B1) ready earlier, PFI was being the missing piece for several months to start testing the PFS instrument system on
the telescope and start an engineering observation. So its delivery and commissioning was a very important milestone forthe project. In fact, to make the best use of the time before the PFI arrival, we devised an additional instrument that enables
to take night-sky spectra on SM1 without PFI. It is Subaru Night-Sky Spectrograph (SuNSS) that is a small telescope systemwith a short fiber cable to deliver photons from the sky to PFS Cable B and then PFS Spectrograph System. It was assembled
at LNA in Brazil and then in Princeton University in USA before the delivery to the Subaru summit. We installed SuNSS on
the Subaru telescope in February 2021 and started SuNSS+PFS observations right away. Until March 2022, ~500 hours ofdata were taken and these have been very useful to develop the data reduction pipeline and characterize the stability ofCable B1 and SM1.
Table 1: The actual timeline of PFS subsystems deliveries andSubsystem Delivered to Hawaii
MCS
SM1
Cable B1SuNSS
PFI
Cable B2

April 2018
October 2019
December 2020
January 2021
June 2021
October 2021

Fully commissioned Origin of the shipment

commissioning. Most of the subsystems were devel-at Subaru summit
October 2019
November 2020
February 2021
February 2021
September 2021
April 2022

oped by a collaboration of multiple other institutes as

to Hawaii
ASIAA (Taiwan)
LAM (France)
LNA (Brazil)
Princeton Univ. (USA)ASIAA (Taiwan)
LNA (Brazil)

well as the one being the origin of the shipment to
Hawaii, and the members of Kavli IPMU were involved
essentially everywhere from various perspectives ofdevelopments and system integration & test at

In FY2021, we obtained two opportunities of on-telescope engineering test. The first period was on September 13-26 2021.
On Sep 13, PFI was successfully installed on the telescope prime focus, for the first time simultaneously together with MCS
and Cable B1 also on the telescope and SM1 in the dedicated clean room in the telescope enclosure building (Figure 1). The
installation of PFI is actually a complex process consisting of two stages: Firstly PFI is put into the Prime Focus Unit so-called
POpt2 that accommodates either Hyper Suprime Cam (HSC) or PFI and integrates it with the Wide Field Corrector (WFC)
lens system. In case HSC resides in POpt2 before PFI installation, HSC has to be removed first and then PFI is installed in it.
Kavli IPMU Annual Report 2021

Meanwhile, during the second period of engineering observation on November 17-21, progresses were limited unfortunately due to some troubles on PFI hardware components and software bugs, but nevertheless we made a few importantachievements:• F or the first time, we managed to take images of bright stars on the sky with the Acquisition and Guide (AG) cameras in
PFI (i.e. AG camera First Light).
• S till some more tests are needed for confirmations, but we got partial but substantial success in the field acquisition andauto guiding processes.
•W e continued to test the performance of Cobras converging to their target positions on the PFI focal plane at different
telescope elevation angles and obtained good results (Figure 2(c)).
Since these on-telescope tests of PFS instrument system began, the software development is rapidly progressing. The
instrument control software is delivered to the Subaru telescope observatory with its hardware subsystem, continuously
developed through the tests to commission the subsystems at Subaru, and then integrated with the system-level layer
through the on-telescope engineering. To operate multiple subsystems in coordinated manners, the operation database(opDB) is a key component. The development is being carried out primarily by Kavli IPMU, and various parts of the schemaare being continually fleshed out as more subsystems are delivered and tested.
Data processing is another area where Kavli IPMU is playing key roles. PFS data are processed in two stages: 2D Data Reduction Pipeline (2D DRP) developed by Princeton University, Kavli IPMU, NAOJ and California Institute of Technology processes spectrograph detector images and delivers fully calibrated one-dimensional (1D) spectra. Then 1D Data Reduction
Pipeline (1D DRP) developed by LAM performs various measurements on the 1D spectra delivered from 2D DRP. In both
2D DRP and 1D DRP, updated versions have been released quite regularly at a reasonably short cadence and become
deployable automatically. Also, a release of 2D DRP comes with simulated spectra and products after reduction processes.
Hence it is worth giving the outputs from 2D DRP to 1D DRP for verifying the entire data processing. Based on this motivation, the infrastructure for such an end-to-end test was set up at Kavli IPMU and the regular data processing has been in
operation since 2020. It has been very useful to discover unexpected problems and issues and steer team’s efforts to resolutions and improvements.

project management, systems engineering, software
Subaru summit.

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Then during the nighttime from Sep 13 to 26 (which were in the period of telescope downtime), various tests were performed using these subsystems. Most of the time we needed to keep the dome closed, but nevertheless we managed tosucceed in completing the major planned test items, for example:•W e confirmed the MCS performance such as image quality and centroiding accuracy using the back-illuminated realfibers in PFI under the presence of dome seeing effect.
•W e understood the PFI focal plane geometry and coordinate transformation between PFI and MCS, and managed toconverge the Cobras/fibers to target positions in ~10um accuracy on PFI coordinate with the telescope pointed to thezenith.
• We took spectral images with SM1 of the forward illumination from the dedicated calibration lamps on PFI as well as the
Subaru facility dome flat lamps.
Then finally, during the night of Sep 26 (i.e. the last night of this two-week PFS engineering campaign), thanks to theobservatory’s permission and the cooperation of the Maunakea’s weather, the sky was observed (with no sidereal tracking
though) through PFI, Cable B1 and SM1! (Figure 2(a) & 2(b)).

Research Highlights

5.5 Commissioning of Prime Focus Spectrograph (PFS) on the Subaru Telescope: The Last
Spurt of Its Development Has Started

This is one-day process. And then on a later day, POpt2 with PFI inside is installed on the telescope. Both processes arecarried out by a few Subaru daycrews and a couple of PFS team members so far. For the PFI installation into POpt2, we
performed a dry run in July 2021 in collaboration with the daycrews, which was an important step for the successful installation at this September run. In addition, MCS has to be installed to the Cassegrain focus beforehand. Needing a specificequipment at two different foci to operate one instrument is a unique requirement of PFS in the Subaru instrument operation, and scheduling all of these in a timely manner for an observation is not trivial at all. But thanks to various considerations
and efforts by the divisions and staffs at the observatory, we successfully installed PFI and MCS on the telescope without
any major problems for starting the night operation.

The team is continuing efforts to deliver more hardware components to the observatory and to perform engineeringobservations for system-level tests for the next couple of years aimed at starting the scientific operation of the PFS instrument from sometime within 2024.
As the instrument development is progressing, the collaboration is in parallel trying to develop a timely plan of large-sky
survey observation to be proposed and conducted in the framework of Subaru Strategic Program (SSP). Having the threemain survey components labelled as cosmology, galaxy & AGN evolution, and Galactic archaeology, the team is aiming ataddressing key questions in the modern cosmology and astrophysics by multiple approaches over multiple scales of dark
matter density structure, which should lead us to comprehensive challenges to the LCDM cosmology. Due to COVID-19,
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Research Highlights

As we will take more data from future on-sky engineering observations, we should be able to better understand the realcharacteristics of the PFS instrument such as its on-sky sensitivity including the accuracy of sky subtraction, the speed offiber reconfiguration, and various stabilities. Accordingly, the team needs to update and re-optimize the PFS SSP survey
plan based on the real performances. But this updating process may not be very straightforward because the commissioning of an instrument is unfortunately often a complex process, and it is very likely even more so for PFS because it is a very
complicated instrument. Appropriate data sets need to be carefully selected for evaluations of instrument characteristics,
and then need to be processed carefully with the pipelines and other tools most of which are still under developments.
Under this circumstance, clearly the interplays between the science team and technical team are crucial, but not only that,coordinated interplays are necessary in order to minimize risks of propagating information that is wrong or too preliminary,and subsequently generating confusion across the collaboration. As part of such coordination efforts, occasionally (butmore often than before the COVID-19 pandemic) collaboration-wide online meetings such as general collaboration meeting and science meeting are organized, and various topics are actively discussed among ~100-200 participants (Figure 3).
The members at Kavli IPMU have been working very hard not only to complete the PFS instrumentation, but also to steer
the entire collaboration into efficient team work during the critical periods for the project in the following fiscal years toachieve ultimate scientific and technical successes of PFS.

Figure 1: (a) [Left] PFI being lifted from the test bench on the floor in the telescope area for the installation into POpt2 later. (b) [Middle left] PFI after the installation on
the prime focus of the telescope. (c) [Middle right] MCS installed on the telescope at the Cassegrain focus. (d) [Right] SM1 operating in the dedicated temperature-controlled clean room inside the telescope dome building to receive photons from the sky through PFI and Cable B1.

Figure 2: (a) [Left] An image showing ~600 spectra of the sky on the spectrograph detector from a 1000-second exposure during the observation in September
2021. This is from the blue camera that covers the wavelengths of 380—650nm. (b) [Middle left] Same as (a) but this is an image from the red camera for
630—970nm. (c) [Middle right] One of the best results for the convergence of fiber positioners Cobra to target positions during the observation in
November 2021. Color-coded are the residual distances in mm to their targets of the fibers moved by the Cobras distributed on the hexagonal PFI focal
plane. (d) [Right] One scene of the team at the Subaru summit in the control room during a night of engineering observation. The team in Hilo and someother people at various other places were participating via Zoom in this run to carry out the observation together.

5.6 Identifying the Origin of Primordial
Gravitational Waves
Valeri Vardanyan
The existence of gravitational waves (GWs) is one of the pivotal predictions of Einstein’s theory of General Relativity. The joint
effort of theoretical and experimental researchers led to the groundbreaking direct observation of GWs [1] in 2015 originating from a merger of two black holes in a binary system. This detection by the LIGO Scientific and Virgo collaborations, alongwith their Japanese counterpart KAGRA, has been revolutionizing the ways we observe the Universe. Besides their important astrophysical implications, they also provide information about the fundamental cosmological scenarios, such as
about the potential existence of primordial black holes [2, 3], values of cosmological parameters [4], and can even probe thelarge-scale distribution of dark matter [5, 6].
GWs do not only originate from the violent mergers of massive astrophysical-scale objects. They can also be produced fromquantum vacuum fluctuations of various fields, and the space-time itself. The latter possibility has been long investigatedand is one of the major, smoking-gun predictions of the cosmological inflation. Inflationary expansion stretches the quantum fluctuations to astronomical scales, which then could be detected by their specific polarization imprint on cosmic
microwave background (B-mode polarization). These primordial GWs generated from vacuum are very weak, and are very
difficult to capture directly. However, the Japanese-led LiteBIRD space mission [7] is designed to measure those in the near
future. Just as the detection of astrophysical GWs discussed above provide us with a crucial new window to the Universe,
the yet-undetected primordial GWs will teach us valuable lessons about the physics in the early Universe. In particular, thedetection of these GWs is linked to the energy at which the inflation took place. It is aslo linked to how much the inflaton
field, the energy source of inflation, can vary — a celebrated relation commonly referred to as the “Lyth bound”. Particularly,
inflationary models designed to take place at lower energies are believed to generate negligible amounts of primordial
GWs, hence rendering such low-scale scenarios untestable.
I have led a research project [8], which involved Kavli IPMU deputy director Prof. Sasaki and colleagues from USTC (China),
where we have challenged this common lore. The idea relies on the fact that while scalar-type perturbations cannot source
gravitational waves in a linear theory, they can perfectly do so non-linearly. While more difficult to analyze because of its
non-linear nature, this opens up a possibility for generating additional gravitational waves during inflation. The quantum
scalar fluctuations during standard inflation should be small in order to agree with the observed amount of clumpiness oflarge-scale matter distribution in the Universe, and the observed temperature anisotropies of the cosmic microwave background sky. As a result their non-linear contributions to inflationary GWs is also suppressed. An important challenge, therefore, has been to construct a scenario where a copious production of gravitational waves during inflation from enhanced
scalar field perdurbations does not require enhanced clumpiness of the structure in the Universe. Such a task has been
considered to be very difficult, if not impossible, by the community. An essential ingredianet of our proposal is the presenceof a second scalar sector, in addition to the standard inflaton. The scalar perturbation modes of the additional sector are
amplified drastically due to resonance effects, which then non-linearly source GWs, without significantly altering theclumpiness of the Universe. The left panel of the figure depicts the time evolution of scalar perturbations of the inflaton field(the dark-red line) which is the source of the large-scale structure we observe in the Universe, and those of the additional
scalar field which is resonantly amplified by more than 5 orders of magnitude during inflation, before the scale of the perturebation becomes larger than the inflationary horizon. The right-hand panel shows the imprint of the produced gravitational waves on the B-mode polarization of the cosmic microwave background anisotropies. The dashed gray line, which isthe prediction of a conventional inflationary scenario operating at a very low energy scale, remains way below the detectable limit (teal-colored solid line). The prediction of our proposal (dark-red solid line), on the other hand, can clearly bedetectable, even though inflation still operates at low energies.

Research Highlights

opportunities to organize in-person meetings have still been very limited, but the team has been continuously updating
and refining the plan in detail through discussions regularly by remote meetings and e-mails.

Figure 3: Screenshots of the participants on Zoom in
the 13th PFS general collaboration meeting.

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Research Highlights

5.7 Could Bizarre Lumps of Q-balls Leave Behinda Hint About How Matter Was Formed?
Graham Albert WhiteOne of the key motivations for believing our understanding of physics is incomplete, is that we have no way of explaining
why the Universe is full of matter rather than being a featureless soup of radiation. Everything we know predicts matter andanti-matter will be produced at equal rates in the early Universe, yet at some stage for the production of every ten billion
anti-particles, ten billion and one particles were produced. To explain this we need new physics!
An elegant explanation for the origin of matter, is that at the end of inflation many scalar fields were far from the value thatminimises the energy. These scalar fields can have non-zero baryon or lepton number and will roll towards the minimum inan elliptical orbit. Therefore, baryon or lepton number conservation is violated right when the universe goes out of equilibrium. If there exists a CP violating operator, the elliptical orbit can be biassed into a clockwise or anti clockwise direction. Thisfulfils all the conditions needed to explain the asymmetry between baryons and anti-baryons and is known as the Affleck
Dine mechanism.

The importance of this study is that we now have a concrete mechanism where the Lyth bound is invalidated – a lowenergy-scale inflation can produce detectable amounts of gravitational waves, without altering the other desirable properties of cosmic inflation. Our results highlight once more the importance of primordial gravitational wave searches throughB-mode polarization of cosmic microwave background (see e.g. [9] for a review). Our findings were published in PhysicalReview Letters in 2021, and were featured as an IPMU press release.

The mechanism is somewhat indirect. We first observe that the scalar fields that violate baryon or lepton number must beflat enough to avoid dominating the energy budget of the Universe during inflation. If a potential is flat enough, there canexist a possibility that the energy of a bunch of quanta with non-zero baryon or lepton number can be lower in extended
field configurations known as Q-balls than they would be in the same quanta of free particles. The most well motivatedmodels in Supersymmetric theories indeed have baryon or lepton violating flat directions that allow a Q-ball solution.

References[1] LIGO Scientific and Virgo Collaborations, Phys. Rev. Lett., 116 (2016) 6, 061102[2] Sasaki, Suyama, Tanaka, Yokoyama, Phys. Rev. Lett., 117 (2016) 6, 061101[3] Bird et. al., Phys. Rev. Lett. 116 (2016) 20, 201301[4] LIGO Scientific and Virgo Collaborations, Nature 551 (2017) 7678, 85-88[5] Canas-Herrera, Contigiani, Vardanyan, 2021, Astrophys. J. 918 (2021) 1, 20[6] Canas-Herrera, Contigiani, Vardanyan, Phys. Rev. D 102 (2020) 4, 043513[7] https://www.isas.jaxa.jp/en/missions/spacecraft/future/litebird.html[8] Cai, Jiang, Sasaki, Vardanyan, Zhou, Phys. Rev. Lett. 127 (2021) 25, 251301[9] Komatsu, Nature Rev. Phys. 4 (2022) 7, 452-469

Second, we note that any decay channel must be inefficient, or loop corrections would spoil the flatness of the potential.
This means that the system prefers to fragment into Q balls rather than decaying into particles. Once these Q-balls form,
there is a minimal amount they can contribute to the energy budget of the Universe in order to explain the asymmetry
between baryons and anti-baryons. Simulations, however, suggest that the system usually fragments into a large amountof both Q balls and anti Q-balls, such that the total energy in Q-balls is typically much more than the bare minimum. In fact,
it can often be within a few orders of magnitude of the total energy in the Universe after reheating.

Research Highlights

As elegant as the Affleck Dine mechanism is, it is notoriously difficult to test with very limited ideas on how to approachtestability in the last three decades. We propose that if we consider various general features of Affleck Dine baryogenesis, it
is very likely that Affleck Dine leaves a signature in the gravitational wave background that can be seen today.

Once these Q-balls form, they generally decay to fermions. This decay rate is already reasonably slow to preserve the flatness of the potential. However, the decay rate is further slowed down by the fact that the decay can only happen at thesurface of the Q-ball. The reason for this is that the large ratio between the energy of a Q ball quanta and vacuum expectation value usually forbids the decay kinematically. However, even if that is not the case, the fermions can quickly fill up the
Fermi sea, meaning further decay within the Q ball becomes Pauli blocked.
These Q-balls dilute as slowly as matter does in the expanding Universe, which is slower than how the rest of the radiation
dominated Universe dilutes. The inefficient decay process therefore means that, usually, Affleck Dine predicts that these Q
balls will dominate the energy budget of the Universe for a period of time. When they do decay, however, the decay accelerates and happens very quickly, as the surface to volume ratio that suppresses the decay rate is rapidly increasing. The collapse of these Q-balls is so fast that the scalar perturbations that were growing during matter domination cannot melt awaywhen the transition to radiation domination occurs. Instead, they form sound waves. These sound waves can constructively interfere with any existing gravitational wave background, including the very small one predicted from inflation. At aparticular frequency, there will be a resonant enhancement of this background which is often visible at the next generationof experiments. This mechanism of secondary production is known as the Poltergeist mechanism.

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Research Highlights

5.8 Exporing Theta-Vacua of Yang-Mills Theories
Masahito Yamazaki

DECIGO

10- 11

LISA
THEIA

10- 9

SKA

ET

10- 13CE

10- 15
10- 9

10- 7

10- 5

0.001

0.100

10

Reference[1] Graham White, Lauren Pearce, Daniel Vagie, Alexander Kusenko, “Detectable Gravitational Wave Signals from AffleckDine Baryogenesis“, Phys. Rev. Lett. 127 (2021) 18, 18, arXiv:2105.11655 [hep-ph]

While the celebrated Yang-Mills theory is one of the most crucial ingredients in Nature, it is notoriously difficult to solve forthe theory in general, even for the textbook-example of the four-dimensional pure SU(N) Yang-Mills theory. Since thetheory is intrinsically strongly-coupled at the low energies, one of the most established techniques for extracting quantitative predictions of the theory is to use numerical methods. The basic idea is simple: we discretize the field theory into thelattice (lattice gauge theory), and the infinite-dimensional path integral is replaced by an integral over a large but finite
number of variables, which integral is evaluated by Monte-Carlo sampling techniques.
While the lattice gauge theories have been successful over the decades, the situation is rather different when we include
the topological θ-term to the theory, which term determines the relative weights of different topological sectors of thegauge fields. In this case, the Euclideanized action contains a pure imaginary term, and the phase of the exponentiatedaction fluctuates wildly—this leads to significant mutual cancellations in the sampling, making the numerical evalution
practically impossible. (This is the notorious sign problem.) It has therefore been a longstanding question to study thedependence of the vacuum free energy f(θ) as a function of the topological parameter θ. We are particularly interested in
the special value θ = π, where we have classically the CP symmetry; the fate of this CP symmetry is correlated with thequestion of whether the theory confines or not [1].
In our recent paper published this year [2] in collaboration with researchers from KEK, we have approached this problem by
N−1
the novel “sub-volume” method (see [3] for a similar method for the two-dimensional ℂℙ model). Instead of turning onθ everywhere on the lattice, we turn on the value of the θ only in a small region (subvolume); this can be regarded as an
insertion of an operator inside the subvolume, in which case one expects that the sign problem is ameliorated. Once wemeasure the free energy for various sizes of the region, we can extrapolate the results to the full volume.
We have applied this technique to the lattice version of the four-dimensional SU(2) pure Yang-Mills theory at temperatures
T = 0 and T = 1.2Tc, where Tc is the critical temperature for the confinement/deconfinement transition. The final results forthe free energies f(θ) as a function of θ are shown in Fig. 1. For T = 1.2c, the f(θ) is well described by the 2π-periodic function∝ 1−cos θ, as one expects from the dilute instanton approximations. For T = 0, however, f(θ) is clearly not a 2π-periodic
function of θ, and instead f(θ) keeps growing past θ = π. Since the Lagrangian in itself is manifestly 2π-periodic, what thismeans is that f(θ) is a multi-valued function, and that we have followed one of the branches in our simulations. That wehave multiple branches in f(θ) was suggested long ago in the large N limit [4]. Our results shows that N = 2 case should bethought of “large N” in this respect, and this furthermore suggests that the theory confines and has a mass gap, as we
observed previously in an earlier publication [5].

Research Highlights

Note that not every scenario that predicts a transition from matter to radiation domination can mimic the signal. The transition has to be faster than the exponential collapse predicted in the standard scenario where a heavy particle decays after aperiod of dominated the energy of the Universe. So not only is it generally true that Affleck Dine baryogenesis generally
leaves a detectable trace in the gravitational wave background, if we do see such a signal, we can narrow it down to a limited number of cosmological scenarios!

We can also promote the θ-parameter to a dynamical axion field, and such axions are discussed widely in particle physics
and cosmology. I myself have worked on this topic in the context of inflation [6, 7] and dark energy [8], and theoreticalconsiderations of the discussed above have many implications there. It is fascinating to contemplate that the predictionsof lattice gauge theories obtained in supercomputers can one day be observed somewhere deep in our Universe.

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Research Highlights

5.9 AI Ethics Score Research
Hiromi Yokoyama
1.2 Tc2
θ /2
1-cosθ∫dθ df/d θ
full volumef(θ) / χ

4
3

10

2

8
6
4

1

2

0
-1

Since 2020, Yokoyama has organized a research group and continues to research AI ethics using AI decision tree analysis. AI
has become an essential technology for society, but there are many ethical issues, and there has been no research to visualize the ethical issues of AI in numerical form. The ethical issues of novel science and technology are called ELSI, an acronym
for ethical, legal, and social issues. The project was named “Score ELSI” to quantify the level of ethical issues in the AI technologies that are actually in use in society.

T=0
θ /2
1-cosθ∫dθ df/dθ
full volume2

12f(θ) / χ

5

14

0

0

�/2

�
θ

3�/2

2�

0

�/2

�

3�/2

2�

θ

Figure 1: The vacuum free energy as a function of the topological angle θ for T = 1.2Tc (left) and T = 0 (right). We obtained these results
3
3
from lattice gauge theory simulations with lattice size 24 × 8 (left) and 24 × 48 (right).
2
	The free energy is normalized by the topological susceptibility χ, which is the theta coefficient of the θ /2 term in the Taylor
expansion around θ = 0. The uncolored circles and triangles represent results from the sub-volume method, with three different extrapolation methods. For T = 1.2Tc the free energy is consistent with the 2π-periodic cosine function, and this is also
reproduced by the full-volume computation. For T = 0 the free energy deviates from the cosine function, and is not 2π-periodic.
In this case the full-volume computation is plagued by the sign problem and is not applicable for θ away from 0, 2π.

References[1]	D. Gaiotto, A. Kapustin, Z. Komargodski and N. Seiberg, “Theta, Time Reversal, and Temperature,” JHEP 05, 091 (2017)[arXiv:1703.00501 [hepth]].
[2]	R. Kitano, R. Matsudo, N. Yamada and M. Yamazaki, “Peeking into the θ vacuum,” Phys. Lett. B 822, 136657 (2021)[arXiv:2102.08784 [hep-lat]].
[3]	P. Keith-Hynes and H. B. Thacker, “Fractionally charged Wilson loops as a probe of theta-dependence in CP(N-1) sigma
models: Instantons vs. large N,” Phys. Rev. D 78, 025009 (2008) [arXiv:0804.1534 [hep-lat]].
[4] E. Witten, “Large N Chiral Dynamics,” Annals Phys. 128, 363 (1980)[5] R. Kitano, N. Yamada and M. Yamazaki, “Is N = 2 Large?,” JHEP 02, 073 (2021) [arXiv:2010.08810 [hep-lat]].
[6]	Y. Nomura, T. Watari and M. Yamazaki, “Pure Natural IInflation,” Phys. Lett. B 776, 227-230 (2018) [arXiv:1706.08522 [hepph]].
[7]	Y. Nomura and M. Yamazaki,“Tensor Modes in Pure Natural Inflation,” Phys. Lett. B 780, 106-110 (2018) [arXiv:1711.10490[hep-ph]].
[8]	M. Ibe, M. Yamazaki and T. T. Yanagida, “Quintessence Axion Revisited in Light of Swampland Conjectures,” Class. Quant.
Grav. 36, no.23, 235020 (2019) [arXiv:1811.04664 [hep-th]].

Many AI technologies are in use in society, and the project took up four examples that are already being discussed in society.
The four examples of AI technology used in the project are Scenario (1) using AI to recreate a deceased singer, Scenario (2)AI-based shopping, Scenario (3) AI weapon, and Scenario (4) AI criminal tracking. We developed a scale that measures thedegree of ethical problems with AI using written scenarios of the possible positive and negative aspects of the above four
AI applications. These results led to the publication of two papers in FY2021.
Paper [1] Octagon Measurement
To date, there has been no research to quantify the problem of AI ethics. What would be a reasonable measure of ethics?
We turned our attention to an analysis of guidelines issued by countries in a worldwide competition; a study analyzing 38
guidelines identified eight common items. These are “privacy,” “accountability,” “safety and security,” “transparency andexplainability,”“fairness and non-discrimination,”“human control of technology,”“professional responsibility,” and “promotion of human values.”The eight items, which are common throughout the world, provide a sufficient basis for quantifying
AI ethics.
We therefore used these eight items to measure the ethical level of Scenarios 1 to 4. Specifically, we asked people in Japanto read the four scenarios and check their level of concern about the eight items. The results showed that of the four scenarios, Scenario 3 (AI drone weapons) was the most concerning, and that people of older age were more concerned about
the use of AI overall. We proposed this eight-item measure of AI ethics, which we named the “Octagon Measure”.

Research Highlights

6

Figure: Octagon measurements for AI ethics.

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Research Highlights

Paper [2] ELSI Score development
We sought a different way to measure AI ethics than the octagonal measure. The octagon measure is suitable for AI ethics,
but it is difficult to use for other advanced technologies because it is based on a guideline analysis of AI. Therefore, we
devised a more versatile measurement method that could be used for other advanced technologies.
We prepared 12 questions about ELSI and measured them in Japan and the US using four scenarios. Using these data, we
performed an AI decision tree analysis and were able to reduce the 12 items to three items—ethics, tradition, and policies—with one item each remaining for ethics, social, and legal issues. We found that, in the future, we can effectively
classify the scenarios by asking about these three items when we study them.
In addition, the combined analysis of Japanese and US data showed that the first item to cause divergence was country,
followed by age. Country and age are major branches in judging AI ethics. We were able to show that the ELSI classification
is useful for comparing and quantifying AI ethics across countries. We are currently developing this research further.

Research Highlights

References[1] Hartwig, T., Ikkatai, Y., Takanashi, N. & Yokoyama, H.M. (2022). ‘Octagon Measurement: Public Attitudes toward AI Ethics,’ International Journal of Human–Computer Interaction[2] Hartwig, T., Ikkatai, Y., Takanashi, N. & Yokoyama, H.M. (2022). ‘Artificial intelligence ELSI score for science and technology:
a comparison between Japan and the US’. AI & Soc. https://doi.org/10.1007/s00146-021-01323-9

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Chiaki Kobayashi awarded a Research Fellowship by the Leverhulme Trust
Chiaki Kobayashi, a visiting scientist at the Kavli Institute for the Physics and Mathematics of the Universe, andAssociate Professor at the University of Hertfordshire, was awarded a Research Fellowship by the Leverhulme Trustin the United Kingdom.
The Leverhulme Trust was established in the United Kingdom after the death of Lord Leverhulme in 1925. Lord
Leverhulme, a committed philanthropist, left a proportion of his company to provide scholarships for research andeducation. The 2021 Research Fellowship grant supports projects, including Kobayashi’s project, in the naturalsciences, humanities, and social sciences

Hirosi Ooguri elected Chair of the Board of Trustees of the Aspen Center for
Physics
Hirosi Ooguri, Director of Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), was elected
the Chair of the Board of Trustees of the Aspen Center for Physics at the general members assembly on July 13,
2021.
The Aspen Center for Physics was established in 1962 to nurture cutting-edge research in physics and related
disciplines by providing a unique physical and scientific environment ideally suited for stimulating interactions,collaborations, and innovation. Every year, more than 1,000 physicists from around the world come to the Center,located in Aspen, Colorado, to ponder, argue, and discover the new ideas that underlie advances in science andtechnology. The Center is an independent non-profit corporation not affiliated with any university and run byscientists and a small number of administrative staff.

Hirosi Ooguri named Benjamin Lee Professor
Hirosi Ooguri, Director of the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), and theFred Kavli Professor of Theoretical Physics and Mathematics and the Founding Director of the Walter Burke Institutefor Theoretical Physics at California Institute of technology, was named Benjamin Lee Professor, it was announced
by the Asia Pacific Center for Theoretical Physics (APCTP) in South Korea.
The professorship was created in honor of Korean theoretical physicist Benjamin Lee, who had a distinguishedcareer in particle physics theory, and invites the researcher to stay at APTCP for an extended period to interact withdomestic researchers and graduate students.

40

Kavli IPMU Annual Report 2021

Young-Kee Kim elected Vice President of the American PhysicalSociety
The American Physical Society (APS) elected Young-Kee Kim, Kavli Institute for the Physics andMathematics of the Universe (Kavli IPMU) Principal Investigator and Louis Block Distinguished Service
Professor in Physics at The University of Chicago, as its next Vice President, it was announced by the APS
Nominating Committee.
The APS was founded in 1899, and is a nonprofit membership organization working to advance anddiffuse the knowledge of physics through its research journals, scientific meetings, and education,outreach, advocacy, and international activities. Currently, there are more than 55,000 members in the
US and around the world. The APS also operates the Physical Review journals.

Eiichiro Komatsu awarded the Inoue Prize for Science
Max Planck Institute for Astrophysics Director and Kavli Institute for the Physics and Mathematics of the Universe
Principal Investigator Eiichiro Komatsu was selected as one of the recipients of this year's Inoue Prize for Science.
The Inoue Prize for Science was established in 1984 by the Inoue Foundation for Science, and presents researcherswith a gold medal and some research funding assistance. The foundation recognizes researchers under 50 who
have made remarkable achievements in natural and fundamental sciences.

Hitoshi Murayama named new AAAS fellow
Hitoshi Murayama, Principal Investigator of the Kavli Institute for the Physics and Mathematics of the Universe and
MacAdams Professor of Physics at University of California, Berkeley, was named a new fellow of the American
Association for the Advancement of Science (AAAS).
The AAAS was established in 1848, with the goal to “advance science, engineering, and innovation throughout theworld for the benefit of all people.” This includes enhancing communication among researchers, engineers, and the
public. Today, the AAAS hosts the biggest science communication annual meeting every year, and is also the
publisher of the scientific journal Science.

Kavli IPMU Annual Report 2021

Awards & Honors

6

AWARDS & HONORSAwards & Honors

41

Invited talks given by the Kavli IPMU researchers (Selected 12 of 179)

Conference title

Attendees(from abroad)

Date

Presenter

Presentation title

Number Theory, Strings and Quantum Physics

287
(209)

Apr. 14, 2021

Thomas Edward Melia

Developments in Hilbert series for
EFT

HEFT 2021 Conference

Hyper-Kamiokande Collaboration Meeting

175
(121)

Jun. 5, 2021

Misao Sasaki

Primordial Black Holes

Quantum Gravity and Cosmology(Sakharov's centennial)

Jun. 15, 2021

Hirosi Ooguri

Stringy Resolutions of Null
Singularities

PASCOS 2021

Aug. 2, 2021

Elisa Gouvea Mauricio
Ferreira

Dark Energy Overview

COSMO 21

Aug. 24, 2021

Meer Ashwinkumar

The XXVIII International Conference
4d Chern-Simons Theory as a 3d Toda on Supersymmetry and Unification
Theory, and a 3d-2d Correspondence of Fundamental Interactions (SUSY
2021)

Aug. 28, 2021

Hitoshi Murayama

Why SUSY is great

SUSY 2021

Aug. 31, 2021

Hiraku Nakajima

Intersection cohomology groups
of instanton moduli spaces andcotangent bundles of affine flag
varieties

68th Geometry Symposium

Sep. 7, 2021

Takeo Higuchi

Belle II: Status and Prospects

The 22nd Edition of Particle andNuclei International Conference(PANIC 2021)

Oct. 12, 2021

Joshua Armstrong Eby

Terrestrial Signals from Axion Star
Explosions

GGI Workshop, “New Physics fromthe Sky“

Oct. 14, 2021

Masahito Yamazaki

Theta vacua in 4d Yang-Mills Theories Strings, Fields and Holograms

Oct. 29, 2021

Shigeki Matsumoto

Summary talk on BSM particle
productions

ILCX2021

Mar. 30, 2022

Satoshi Shirai

Progress on the study of QCD axions

What is dark matter? 2022 Comprehensive study of the huge
discovery space in dark matter

Date, Place

1-4 June 2021, [Online]

7-18 June 2021, [Online]

Quarkonia Meet Dark Matter
15-18 June 2021, [Online]

Focus Week on Quantum Mechanical Systems at Large Quantum Number
30 August - 3 September 2021, [Online]

Particle Acceleration in Solar Flares and the Plasma Universe --Deciphering Its Features
Under Magnetic Reconnection-15-19 November 2021, [Online]

The World of Mathematical Physics II

119
(70)
46
(44)
155
(126)

21 November 2021, [Online]

84(4)

Dark Sectors of Astroparticle Physics (AstroDark-2021): Axions, Neutrinos, Black Holes andGravitational Waves

174
(107)

7-10 December 2021, [Online]

New Observational Windows on the High-Scale Origin of Matter-Antimatter Asymmetry

79
(70)

Hyper-Kamiokande Collaboration Meeting

145
(84)

Cosmic Cartography 2022: Exploring the Cosmic Web and Large-Scale Structure

199
(145)

PFS 13th Collaboration Meeting

186
(95)

What Is Dark Matter? - Comprehensive Study of the Huge Discovery Space in Dark Matter -

149
(12)

10-14 January 2022, [Online]

14-25 February 2022, [Online]
7-11 March 2022, [Online]

22-24 March 2022, [Online]
29-30 March 2022, [Online]

42

8

CONFERENCE PRESENTATIONSAND SEMINAR TALKS

Kavli IPMU Annual Report 2021

Conference name

Kavli IPMU Annual Report 2021

Conference Presentations and Seminar Talks

7

CONFERENCES

43

9

OUTREACH AND
PUBLIC RELATIONS
DATE

VENUE

number ofparticipants

The 24th ICRR & Kavli IPMU Joint Public Lecture"The Wonders of a Universe Full of Matter"

Apr. 10, 2021

Online1,173

Film Screening"Secrets of the Surface: The Mathematical Vision of Maryam Mirzakhani"

Apr. 25, 2021

Online452

Celebration of Women in Mathematics

May 15, 2021

Online353

Fundamentalz Bazaar

Jun. 6, 2021

Miraikan

431

Science Café 2021 "Universe"

Jun. 20, 2021

Online48

Go Global Gateway Online Event: Film Screening"Secrets of the Surface: The Mathematical Vision of Maryam Mirzakhani"Aug. 6, 2021

Online64

Collaborative Knowledge Creation Practical Learning Course with the
University of Tokyo CoREF"Learning and Creating Physics - From High School to the Forefront
Research of the Universe"

Aug. 4-5, 7, 2021

Online77

Science Café 2021 "Universe"

Sept. 19, 2021

Online51

Kashiwa Campus Open Day, 2021

Oct. 23-24, 2021

Online8,667*

6th “Actually I Really Love Physics!“–Career Paths of Female Physics
Graduates

Nov. 6, 2021

Online48

Kavli IPMU x ICRR Joint Public Lecture: “A Dream of Modern Mathematics. A
Cutting Edge of Physics“

Nov. 28, 2021

Online394

10th Annual WPI Science Symposium: “To the Future NanoWorld“

Dec. 18, 2021

Online567

7th Kavli IPMU/ELSI/IRCN Joint Public Lecture: “A Question of Origins“Jan. 30, 2022

Online595

Mar. 19-25, 2022

JR UenoStationPlatform 13

200

EVENT TITLE

Fundamentalz Festival mini: An Exhibition of Work by Artists andResearchers*Total number of participants to all institutes on the Kashiwa campus

44

Kavli IPMU Annual Report 2021

April 2021–March 20225-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan

TEL: +81-4-7136-4940

FAX: +81-4-7136-4941 http://www.ipmu.jp/

ISSN 2187-7386

Printed in Japan

Kavli IPMU

Annual Report 2021

Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU)
The University of Tokyo Institutes for Advanced Study
The University of Tokyo