Where Fundamental Physics meets Diversity

Hirosi Ooguri is a Fred Kavli Professor of Theoretical Physics and Mathematics and the director of Walter Burke Institute for Theoretical Physics at Caltech. His areas of focus are on quantum field theory, quantum gravity, and superstring theory. He is working to discover mathematical structures in these theories and to use them to invent new theoretical tools to solve fundamental questions in physics. A native of Gifu, Japan, Dr. Ooguri received his BA and MA at Kyoto University and earned a Ph.D. from the University of Tokyo. He was a member of the Institute for Advanced Study in Princeton in 1988-89 and was appointed an Assistant Professor at the University of Chicago before receiving his Ph.D. in 1989. After four years as an Associate Professor at Kyoto University, he returned to the United States in 1994 as a Full Professor of Physics at the University of California, Berkeley. He has been at Caltech since 2000, leading the establishment of the Walter Burke Institute for Theoretical Physics in 2014 and serving as its Founding Director since then.

Dr. Ooguri also helped establish the Kavli Institute for the Physics and Mathematics of the Universe at the University of Tokyo in 2007 and became one of its Founding Principal Investigators. He served as the Director of the Kavli Institute from 2018 to 2023. In 2024, the University of Tokyo named him a University Professor.

A General Member of the Aspen Center for Physics for twenty years, Dr. Ooguri was elected an Honorary Trustee for Life in 2023. He has served as the Scientific Secretary, a Trustee, and the President of the Center. Since 2021, he has been the Chair of the Board of Trustees.

Dr. Ooguri has also been named the Louis Michel Chair of the Institut des Hautes Études Scientifiques in France, with the appointment to start in 2025.

His many awards include the Eisenbud Prize for Mathematics and Physics from the American Mathematical Society, the Simons Investigator Award from the Simons Foundation, the Guggenheim Fellowship, the Hamburg Prize and the Humboldt Research Award in Germany, the Benjamin Lee Distinguished Professorship in South Korea, the Frontiers of Science Award from the International Congress of Basic Science in China, and the Nishina Memorial Prize and the Chunichi Cultural Award in Japan. In 2019, the Emperor of Japan conferred to Dr. Ooguri the Medal of Honor with Purple Ribbon. 


IROHA: What drew you to physics? And when did you realize that you wanted a career in research and teaching?

Dr. Ooguri: I grew up in a rural area, a small city between Tokyo and Kyoto, where my parents were running women's clothing stores. My parents do not have science background, but fortunately, they were very invested in our education.

For example, there was a big bookstore in my neighborhood, three-stories high with full of books on each floor, the biggest in the prefecture. I used to go there almost every day. I usually just browsed books, but when I found one I really liked, my parents would buy one for me. They did not tell me which ones to read; they just let me follow my curiosity. It opened up my world.

But there was a particular experience that drew me to science. I'm a physicist, and physics is different from other areas of science in the following sense. When you say biology, you study living objects, and when you talk about astronomy, you study stars and galaxies. And when you say geology you study the earth, right? With these branches of science, each name is associated with the objects you study. But physics is not about a particular object. If you are in high school and you study physics, you may think it’s about how the trolley goes up and down the slope or something. Rather, physics is a method to study nature. The idea is to understand the fundamental principle and then try to deduce everything from that principle.

That kind of approach is what physics is about, and that method can apply to many things. For example, if you apply it to the property of an atom, then we have atomic physics. When you apply this physics method to the universe, we have astrophysics, and if you apply that to understand the earth, we have geophysics. So, we have variety of physics depending on what you study. Nowadays, there are even subjects like information physics and econophysics.

I experienced this first when I was in fifth grade in elementary school, ten or eleven years old. My parents used to take me to Nagoya every weekend to do some shopping. We often went to this big, tall building, and on the top of it is a revolving restaurant, which I really liked. We used to have lunch there before we went shopping.

On a clear day you could see the horizon. We were having lunch, and I was wondering, “how far is the horizon?” In elementary school, we learned how to measure how tall a nearby telephone tower is using the similarity of triangles. I thought maybe we can apply the same idea to measure the distance to the horizon.

While eating the lunch, I figured out that the answer is the geometric mean. It's the square-root of the product of the height of the building and the radius of the earth. And I knew the height of the building because, I was a fan of monster movies. And in monster movies, there are monsters that come and knock down buildings. For example, Ultraman, which is one of the heroes, his height was 50 meters. And the building was slightly lower than that, so it must be something like 40.

But I didn't know the size of the earth, so I thought I couldn't calculate the distance to the horizon. Then I noticed that near the horizon there was my father’s hometown. I asked my father how far his hometown was, and he said about 20 km.

Since this is an equation between the radius of the earth, the height of the building, and the distance to the horizon, if you know two numbers, you can figure out the third. I was able to calculate on the spot the radius of the earth. I was like, wow. I was just sitting having lunch with my parents and just knowing that building is about the size of Ultraman, I figured out the size of the earth, right? So that's pretty cool.

That's my first experience of understanding something fundamental, by observing nature carefully and thinking deeply. At the bookstore there was a series of biographies aimed at children. Roughly speaking, one third of those were about scientists like Einstein, Marie Curie, Newton. Around the time, Japan was in a huge economic boom, and it was also right after the Sputnik shock in the US. Scientists were my heroes around that time. I thought this is something I want to do.

IROHA: Today you work for various organizations in different cities around the world. How do you find the balance?

Dr. Ooguri: Yeah, that's challenging. There are two challenges. One is managing being a scientist and at the same time, doing administration. And the other is to deal with different administrative roles.

Managing the role of a scientist and an administrator is challenging because being a scientist requires concentration. The role of scientists is to discover the truth in nature. For thousands of years humans have worked on this, so you have to think very carefully and deeply to get something new. It requires concentration, so you need a block of time to do that. If you get interrupted, then you have to go from the beginning. It's very important to keep the block of time that you don't get disturbed.

But, if you are doing administrative work, you get interrupted all the time. Often what I try to do is to keep all my morning hours for my research and try not to do any administrative work. Of course, there are emergencies I have to deal with sometimes. But, except for them, I try to focus on my research in morning. And then in the afternoon, I meet with my students and do administrative work.

Administrative work is in some sense more tempting because many administrative problems are easier to solve. In research, we try to solve difficult problems. I'm trying to find something that no one has discovered for the past thousand years. On the other hand, administrative works are often quite routine and easier to solve. So, there is a temptation to solve simpler problems if you are faced with difficult work that you have been working for a long time and do not know where to go. If you get some inquiry and administrative issues, there is a temptation to work on it rather than continuing thinking about difficult problems. You have to manage this, too.

I'm Fred Kavli Professor at Caltech. Mr. Fred Kavli was a Norwegian philanthropist who passed away a few years ago. He donated several chairs to universities and gave endowments to many research institutes. I have benefited from the Kavli Foundation in many ways: I hold the Kavli chair, and I was also, until October, the director of Kavli Institute for the Physics and Mathematics of the Universe at University of Tokyo. I'm also the director of the Walter Burke Institute for Theoretical Physics at Caltech. Mr. Walter Burke was the chair of the board of trustees of the Sherman Fairchild Foundation. Sherman Fairchild was a very successful businessman in the aerospace industry and the semiconductor industry and started the predecessor to Intel.

I helped raise about $30 million to start the Walter Burke Institute from the Sherman Fairchild foundation and the Gordon and Betty Moore Foundation. My role there is to manage this funding, which has grown to about $65 million, so I need to figure out how to distribute it. Most of the use of the money is to support postdoctoral fellows, researchers who just received doctoral degrees and are starting to do research before they get faculty positions. 97% of our former postdocs have faculty positions at prestigious universities. It has been a very successful program.

I'm also the chair of the board of trustees of the Aspen Center for Physics. And this is a very interesting institution. It is run by physicists volunteering their time; it's not associated with any universities. I have been helping the center for about 20 years. And I was the president of the center a few years ago. When I stepped down, I thought, well, I have done my share, but then I was asked to come back as the chair of the board.

The third administrative role I have is at the University of Tokyo. In 2007, I took a sabbatical and decided to spend three months in Tokyo. In fact, that was the year when my daughter was going to the first grade in elementary school. I thought it would be nice to start her first year in Tokyo, too. There is a Japanese phrase “pika pika no ichi nen sei” (“bright and shiny first grader”), so we wanted that for her.

This was an interesting coincidence because in the spring of 2007, the Japanese government announced a new, very exciting program, which aimed to identify the area they wanted to reboot Japanese science. They wanted to identify some area of science that Japan is particularly good at and put more money into that and build a world-class institute.

While on sabbatical in Tokyo, I helped the University of Tokyo write a proposal and defend it at the interview. And then it was funded, to my surprise. We called it the Institute for the Physics and Mathematics of the Universe. We wanted to have the institute where both physicists and mathematicians come together to produce new ideas to solve fundamental problems about the universe.

It was also the year that Mr. Kavli was turning 80, and there was a big party in Santa Barbara. I was invited as the Kavli Professor in Caltech. I went there, and I met board members and told them about this very interesting initiative in Tokyo. And they got interested. They actually came to visit Tokyo the year after. And then a few years later, they decided to endow the institute, so it became the Kavli institute for the Physics and Mathematics of the Universe. I have been a Principal Investigator of this institute since it started.

Five years ago, I was asked to become the director. My wife said, “Well, that's very challenging because you have to be at two places at the same time.” I wasn't sure how I could manage it. Caltech, fortunately, allowed me to do 50/50 appointments for five years. At many universities in the United States, they allow one day out of five working days in a week for consulting, 20 percent of time. Mine was a special case because at Caltech, astronomy is a big deal, and Caltech was involved in many astronomy projects with Japan. I wasn't sure I could manage this, but then the pandemic hit, and we learned that we can do some administrative work remotely.

Of course, I mean the pandemic was a very tough thing for all of us. But in some sense, it also let people realize that there are many things that people wanted to do but didn't do – we are doing this interview online, for example – and streamlining some of the administrative procedures. That accelerated during the pandemic. During the first two years of the pandemic, Caltech did not allow its faculty members to travel internationally. So, I couldn't even go to Tokyo, but I was able to do most of the administrative work remotely. We had a very talented group of  administrative staff in Tokyo, so that was very helpful. But, you cannot be the director without being at the location in-person, so as soon as that period ended, I started going there regularly.

IROHA: What initiatives are you involved in that encourage young scientists, especially women?

Dr. Ooguri: This is something I feel very passionate about. Young people are our future, and they decide where the field goes. Diversity is very important for science. In order to make progress in fundamental science, we need a variety of ideas, and we need to be open to new ideas.

When I became the director of the Kavli Institute for the Physics and Mathematics of the Universe five years ago, I set myself two missions. One is to make the institute permanent. It was funded by this Japanese government initiative for 15 years, but that was to be ending during my term as the director. We have succeeded in setting up an annual budget of about $10 million in the core funding category of University of Tokyo, so that funding is secured for the foreseeable future.

Another mission was to improve the equity, diversity, and inclusion of the institute. Diversity is particularly lacking in Japan, especially in science, physics, and mathematics. In many universities in the US, there have been improvements in science and engineering over the last couple of decades, though it needs to be improved more. For example, my daughter went to the engineering department in Cornell, and in the year she entered, it was 50/50 between female and male undergraduates. In 2000 when I moved to Caltech, it was very much a male-dominated school with lots of boys but very few girls. But now when I walk on campus there are almost equal numbers of males and females.

What I can do is to improve the diversity at the postdoctoral level. As a director of an Institute at Caltech, the main use of the resources is to fund post-doctoral fellows, so I can make a difference there. Every year we hire about ten or twelve postdocs, and for the last few years, the fraction of female postdocs has gone up to about 30%. It is more than the percentage of the undergraduate female population in physics. At the Kavli IPMU, this year, the percentage of postdocs funded by the IPMU operating fund became 40%. So, we have had quantifiable successes.

One of the things that we realized is that if you look closely there are really good candidates. We have a selection committee. There are various areas of physics and mathematics, and we invite experts in each area to look at the application list and bring candidates. I request that each of them bring candidates who would improve the diversity of our fellowships. We go through the list and rank them, and then we see whether there are any candidates who are comparable to people whom we decided to hire and who would improve the diversity. Often, we find them, and we can incentivize that by having extra positions for them. I think similar initiatives can be applied to other levels like students or faculty members.

There are other things like, for example, conferences. I'm requiring that, first of all, we have to have codes of conduct both for the Institute as a whole and for the conferences and other activities we organize so that everybody knows what the expectations are. For conferences, we need to make sure that both organizers and the list of invited speakers reflect the diversity of the field. In physics and mathematics, people are very competitive and sometimes I see aggressive behaviors. We have to be careful about those things. Aggressive behavior may come by just purely out of curiosity or a pursuit of excellence and wanting to understand the truth. But they can lead to very intimidating behavior. I think that the improvement of diversity can come not only from the hiring area, but also managing the behavior of constituents and participants.

IROHA: What has been your experience with Asian hate?

Dr. Ooguri: In some sense, I have been very fortunate because I have not experienced [anti-Asian hate] myself. And that's partly because I have been in academia where people are in some sense more enlightened about this issue than the general population.

I work in the area of science, where achievements are easily quantifiable and measurable. If you are working on something more subjective, such as art or music or literature, it might be more difficult to compare and remove biases. Moreover, I live right on campus, so I have not personally experienced it. But I do understand what you mean. I've known people who are affected. I know people even within academia who have experienced some violence, and that's very disturbing.

Another thing that—this is not something I personally experienced, but I observed it on various occasions—is that there are some subtle biases against East Asians. There is a perception that East Asians are diligent workers, they're very trustworthy, they do their jobs very well, but they are not innovators, they are not creative, they don't have vision, and they don't have leadership. I think that’s the perception that people often experience. We can see it in how rare East Asians are in leadership positions. Even in academia, academic leadership such as presidents of universities, provosts, there are very few East Asians compared to the number of faculty members of East Asian origin. And that's surprising because if you look at who is working in science and engineering, there is a significant number of East Asians. It's very hard to explain why that is, but I just wanted to point it out.

IROHA: Since you are so deeply involved in DEI with students and the postdoc fellows, is that also something that you’re championing, that eventually more universities will hire East Asians as presidents?

Dr. Ooguri: I don’t particularly think there is an issue with the hiring of East Asians, at least in my area of research. But I'm just pointing out that I do observe that there are many places that are not my profession but outside of my profession, where I can see that, based on some reasonable measure, there could have been more East Asian representatives.

IROHA: Outside of academia, what are you interested in?

Dr. Ooguri: I like to be useful. One of the things I think I can do well is public outreach. I write outreach articles, and I often give public lectures. And I helped to produce a science movie, which has been translated into six languages and received some major awards. I'm doing this mostly as my volunteer work.

IROHA: Outside of work, what interests do you have?

Dr. Ooguri: I do not practice music; my physical capacity is very limited, but I like listening to classical music. I like reading books, both fiction and nonfiction. Like I said, I was very fortunate that I was living near a big bookstore when I was small. It is sad to see that bookstores are now closing. It is hard to find a nice physical bookstore these days where you can browse books. I also go to museums. I like to admire the achievements of humans. And like I said, my parents ran an upscale clothing store for women, so I like fashionable things, too.

written by Susan Miyagi McCormac

 Hirosi Ooguri | Caltech