Vol.06　Hitoshi MURAYAMA

Professor Murayama, who founded the Kavli IPMU located on the Kashiwa campus of the University of Tokyo, is a particle physicist and the principal investigator on the team using the Subaru Telescope to investigate the mysteries of the universe with cutting-edge science. While pushing ahead with research activities through constant travel between the United States and Japan, he gives lectures in various places, appears on TV programs, and writes a series of articles for a national newspaper in Japan. His energetic activities span a wide range of issues. We talked to Professor Murayama to hear about his work at the forefront of science, and to find out more about the background of this amazing person with seemingly unlimited energy.

The many people who have come in contact with Professor Murayama describe him as friendly, having a wealth of knowledge and the surprising skill of being able to explain even difficult scientific topics in a way anyone can understand. What kind of life did he have up to now? We started out by asking him about his childhood.

“As an elementary school kid, I had terrible childhood asthma. I was absent from school for a frightening number of days throughout the school year. Two times a month, I had to get an IV drip of adrenal cortical hormones, and was told I would have a moon-shaped face, so things were really terrible,” said Professor Murayama.

But, his struggle with this illness provided an opportunity to discover a deep talent within him.

“When you take time off from school and are home during the day, you usually watch TV, right? But, for me, daytime dramas weren’t very interesting since I was still a child. So, I started watching what is now called NHK E Television, or what in the old days they called NHK Educational TV, and found some really interesting programs there.”

For example, in the math program, there was a RAKUGO, a traditional Japanese comic storytelling, explaining how “an infinite series converges,” which is a part of high school mathematics.

This amusing example went like this: “A customer went to a tofu shop to buy tofu, and after buying one block of tofu, he started to flatter the shop owner, saying, ‘Everybody says your tofu is the best-tasting tofu in all of Tokyo!’ The shop owner liked hearing this and said, ‘Oh really? Well, I’ll give you half a block tofu for saying those nice things.’ The customer then said, ‘You are really a generous person, so everybody comes here to buy tofu.’ The shop owner then said, ‘That’s great, I’ll give a half of the remaining half as a ‘Thank you!’ and …”

Professor Murayama continues the story as if he himself were the storyteller.

“This kept going with the shop owner saying, ‘Okay! Okay! A half of the remaining half! A half of the remaining half! I’ll give you everything still remaining!’ The customer, hearing this, thought: ‘Great! I’ll have enough tofu to last the rest of my life!’ And yet, when he looked in the bowl, there were only two blocks of tofu. One block was the tofu he bought initially; half of the other block of tofu was given to him by shop owner; and half of the remaining half, that is, a quarter of one block, then one-eighth of one block…. yet it all added up to only two blocks.”

Later on, his father was transferred to Germany, and Professor Murayama went to the newly-built local overseas Japanese school there, where he demonstrated his character.

“One thing I still remember from the local Japanese school is my social studies teacher. One day this teacher was talking about why there are the four seasons of spring, summer, fall and winter. He explained that the earth spins on a tilted axis, so Tokyo, which is in the northern hemisphere, gets a lot of sunlight in summer. On the other hand, in winter, the earth is in a position opposite that of summer so the southern hemisphere faces more toward the sun and gets lots of sunlight. “I heard this explanation and thought, ‘Wow, so that’s how it works.’ Though still a child, I felt really impressed by all this.”

Professor Murayama, who was then a junior high student, asked the social studies teacher a question. “Well then, the equator has summer two times a year, right?”

The earth spins on a tilted axis, so during Japan’s summer solstice (midsummer) the northern hemisphere faces the sun, and in the winter solstice (midwinter), the southern hemisphere faces the sun. During the vernal equinox and fall equinox, which fall between those periods, the equator is facing straight toward the sun, so when I said, “The equator has two summers” the teacher replied, “Such a stupid thing can’t possibly happen!”

“This got me really mad. Then I did the only thing I could and went to the school library. A look at the temperature graphs for each world region showed that Nairobi in Kenya, which is close to the equator, does in fact have summer twice a year.”

When he showed that book to the teacher and said, “Look, the equator does have two summers,” the teacher said nothing at all and was speechless. “From the teacher’s point of view, I must have really been an annoying child to deal with,” says Professor Murayama.

For the boy Murayama, the idea that the equator has two summers was “a theoretical prediction verified by an observed phenomenon.” Verifying a prediction by data was really the scientific method. Following the scientific method by investigating it in the library showed that the prediction was in fact accurate. In other words, the issue of summers near the equator was solved by applying the scientific method.

How did the boy Murayama learn to apply the scientific method? “I guess, when I was a child and full of curiosity and asked things like ‘Why is it that…?’ or ‘Why does it become that way?’, my father, who was also a researcher, would always give a definite reply. If he couldn’t give an answer, then he would go buy a book providing the answer.”

Spending childhood in such a way helps create the belief that things that may first appear mysterious always have a definite explanation, so encountering a mystery makes one want to solve it.

There are many children like the boy Murayama in elementary school who are full of questions about the world around them and ask adults about the questions they have. But adults often tell children there is no time to give answers, and offer comments like, “Don’t worry about stupid things like that; go do your homework,” or “Eat your dinner first,” or “It’s time for your bath.” They use excuses like this to kill the child’s inquisitive spirit.

“That child then becomes discouraged, believes his question is worthless or that there won’t even be a reply to his question, and totally gives up asking about things,” says Professor Murayama. He continues: “But things could be a lot different if the parent says, ‘Well now, let’s think about this together or let’s investigate this’ when the child asks a question.”

Professor Murayama lived in Japan through the fifth grade of elementary school and from the sixth grade through junior high school attended the local overseas Japanese school in Germany. How did he view his life in another country? 

”Living in Germany was interesting. I was also happy because it was a different environment and I was finally healthy. But besides all of that, just driving by car for a few hours brought me to another country. It was something you cannot experience in Japan.”

The Murayama family lived in Dusseldorf. The border with Holland (Netherlands) was close by, so on weekends he and his parents drove two hours by car to go shopping in Holland. At that time there was no European Union and no Euro. Crossing a country’s border meant a big difference in prices for goods, e.g., buying vegetables in Holland was much cheaper than in Germany.

As they drove from Germany toward Holland, the language also changed. “Namely, as we neared the border, the words people used changed gradually from German to a German dialect and then to the Dutch language.”

For example, the greeting “Good Morning” is “Guten Morgen” in German, but as you near the border this becomes “Yuten Morgen” and finally when you cross into Holland it becomes “Goedemorgen.” The word “Thank You” is “Danke” in German but in Dutch it is “Dank u” which is similar to the English phrase “Thank you.”
“So, words are not something precisely grouped into particular languages and the feeling I get from knowing they are connected to each other is interesting to experience. For example, when buying biscuits at a pastry shop, you will see the main ingredients such as flour and sugar listed in 10 different languages.”

Countries that link to different adjoining countries are a special feature of Europe. Various types of people are linked together in some way but have different lifestyles, and the feeling that this is totally natural is something you don’t see in Japan. What Professor Murayama experienced in Germany would affect him throughout his subsequent career.

“I don’t feel any inner resistance to going overseas. I no longer feel any inner resistance to places where I don’t know the language or to different cultures. In other words, I have a feeling that things will somehow work themselves out,” says Professor Murayama.

How did Professor Murayama first get involved with his specialty of elementary particle physics?

“At a seminar in my third year at college, I read for the first time a book on elementary particle physics, and found it extremely exciting. I knew from my high school days that everything around us is made up of atoms, that atoms have an atomic nucleus, and the atomic nucleus contains protons and neutrons. But this book was the first time I heard about the quarks that are in protons and neutrons, the forces acting between these quarks and their properties, and how these particles were discovered. And all of this was written like a historical novel.”

In the summer of the fourth year at college, Professor Murayama couldn’t make up his mind about whether to take a graduate school entrance exam or make a living from music. But he couldn’t shake off the appeal of digging into things to see what more he could learn. So he decided “if it’s going to be physics, then I’ll go with elementary particle physics that deal with the tiniest things.” And so, he went on to graduate school.

However, he ran into a roadblock again. In the elementary particle theory research lab he joined, nobody was researching elementary particles.
“At the time, that research was regarded as out-of-date. When I told the teacher ‘I want to study this (elementary particles),’ the teacher ridiculed me, saying, ‘Why do you still want to do that stuff now?’ So I found myself completely alone at the research lab.”

“At one time, outside lecturers were invited to hold intensive courses at our school.” One of them was one of the few researchers in Japan studying traditional elementary particle physics and he gave a lecture that met Professor Murayama’s expectations. After the lecture, the student Murayama ran up to him and asked to be taught by him. The researcher’s reply was, “Okay, I can teach you, but I will be in the UK for the next two years, so maybe I can teach you when I get back here.”

Two years later, that researcher came back to Japan, and, again, Murayama asked to be taught by him. “Yes, I remember saying I would teach you,” the researcher replied. “But teaching just one person is not very efficient, so find at least 7 students to study along with you.”

“This was a completely unpopular field of study, so I went and persuaded one person at Hiroshima University, two persons at Kyoto University, two persons at the Komaba campus of Tokyo University and two junior students to get the total of 7 persons. In this way, I finally gathered 7 people. A special course then started.”

This was March in the second year of his PhD degree course. That meant he had to complete his doctoral thesis by December that same year. The next eight months starting from April would be an important period that would decide his future success or failure.

”In those eight months, I worked and studied really hard. This was the first time I was able to study what I wanted to study. I kept trying, worked on various types of calculations, and wrote up and submitted my doctoral thesis. However, my paper was almost rejected!”

In most cases, the doctoral thesis review consists of an open process and then shifts to a closed process where the students are questioned by the examiners. Once that is finished, the students leave and the examiners start their discussion. Usually, the students pass the review almost immediately, and if they wait outside, the chief examiner comes out before even five minutes are up and offers congratulations to the student.

“However, I was told ‘Return to the research lab’ instead of waiting outside the room. In the research lab I waited five minutes, then 10 minutes, then 20 minutes but nobody came. After about 30 minutes, a teacher—instead of the chief examiner—finally came.”

Professor Murayama’s doctoral thesis was related to developing software that allowed calculating difficult reactions that had been impossible to calculate up to that time when observing reactions in elementary particle experiments. This involved actually creating software and summarizing various simulation data on a computer. However, the teachers reviewing the experimental side said, “This is not experimental data; these are just calculation results,” and the teachers reviewing the theoretical side said, “This isn’t a theory; this is just computer software.” The meeting to judge his thesis turned out to be a terrible affair.

“After all, ‘Unless you can make these types of calculations, you won’t understand the results—even if you complete the experimental work.’ And so, they apparently accepted my thesis with kindness. Maybe the thesis and contents were bad,” says Professor Murayama. This software in fact has now been used for more than 30 years all over the world. But even though it had tremendous value, almost nobody realized it at that time.

Professor Murayama found that he was unable to do the research he wanted in Japan, so a few years later, he decided to go to the United States.

After consulting with various people and thinking about where to go, Professor Murayama decided on UC Berkeley. Looking back on that time, he says with a laugh, “It was a sudden ray of sunshine in my life.”

Professor Murayama saw many talented people at UC Berkeley. He says, “There was a very strange person. He was also the legendary physicist and Nobel Prize winner Luis Walter Alvarez, who discovered several elementary particles. His most famous paper is the ‘Dinosaurs were killed by an asteroid impact’ theory.”

Elementary particles and dinosaurs —in the eyes of an amateur, these are not related, but Professor Luis Alvarez made the connection within his head. “The point here is that a person making elementary particle experiments must have the ability to search out and perceive reactions that rarely occur. For example, that person must have the skill to very accurately sense even minimal quantities of an element.”

Professor Luis Alvarez discovered a highly rich deposit of an element called iridium in a stratum near the Yucatan Peninsula in Mexico. Iridium is extremely rare on our planet but is contained in large quantities in meteors and asteroids coming from outer space. Professor Luis Alvarez therefore thought to himself that an asteroid was the likely source of this stratum.

When he next investigated the age of the stratum, he found it was exactly the time that the dinosaurs became extinct. That is when Professor Luis Alvarez made the connection within his head, “This asteroid is the reason why the dinosaurs became extinct.” Professor Murayama comments, “The archeologists at that time never even considered an asteroid as the reason for the dinosaurs becoming extinct. ‘A physicist came along and said something strange.’ Now his ‘Dinosaurs were killed by an asteroid impact’ has become an established theory.”

UC Berkeley is a place full of the kind of free thinkers you would never encounter in Japan. The culture there has created a mind-set where one is not bound to a particular field; rather, one is free to apply all of one’s own skills to “solving the problem because it exists” or because “it is an interesting problem to tackle.”

In October 2007, Professor Murayama became the founding director of an organization then called the Institute for the Physics and Mathematics of the Universe (IPMU). He says, “I originally had no intention of becoming director. I was asked to write up some organization planning and accidentally became its director, so it all just sort of happened.”

At that time, the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) had launched projects with the goal of achieving “World’s top-level research standards,” “Creating interdisciplinary fields,” “Forming an international research environment” and “Innovating our research organizations.” The projects would be part of the World Premier International Research Center Initiative (WPI), whose goal has been to create research centers having global appeal for the world’s top-level researchers. The University of Tokyo, which has been part of this undertaking, asked for a consultation with Professor Murayama, who was then working at UC Berkeley. They explained that they were gathering researchers in the fields of theoretical physics, experimental physics, mathematics, and astronomy—and planning to create a new research lab with the above concepts in mind. And they asked him how to first go about creating the proposal planning for the initiative.

Hearing this question, what immediately sprang to Professor Murayama’s mind was an image of the roughness of the universe after the Big Bang. He told them, “The theme for this new research lab is the universe.”

”This miniscule roughness of the universe can in one way be thought of as sound. Sound travels through dense and thin locations in air and the Big Bang was the first sound in our universe. Such a sound can be described by mathematics, and how this sound became a star is physics, and the observation of this phenomenon is astronomy . . . I proposed to use this approach. Anyway, let’s just say that this new research institution links mathematics, astronomy and physics along an axis that spans the universe.”

The University of Tokyo also told Professor Murayama that they wanted him to be the director of this new institute. Professor Murayama was 42 years old at the time and the research institution budget for a 10-year period was 13 billion yen.

“I thought there was no way that this large budget would be entrusted to a young man in his forties. Moreover, I had almost no experience in working in Japan, and on top of that, I thought that Japan would not spend money on a field such as outer space—which offered no actual profit,” says Professor Murayama. He continues, “Anyhow, I wrote up the requested planning proposal, listing my name as the founding director, and submitted it, but quite honestly, I thought it would never be approved. However, the planning was in fact approved!”

One-third of the planning examiners were foreigners, from which I conjectured that they thought, “Well, the goal of this program is to change Japan, so let’s approve this plan and give it a try. The overseas examiners probably thought that it would be okay to approve at least one of these somewhat odd planning proposals,” says Professor Murayama with a laugh.

Professor Murayama’s tour of duty as the institute’s director ended last year.  What will be his next goal?

“What I really want to focus on right now is discovering the real nature of dark matter. Dark matter can be thought of as our ‘mother,’ so I would like to meet her. There are now many ways available to investigate dark matter, so I feel we might soon be able to grasp some real knowledge about it.”

What is the next goal, after dark matter?

He says, “I stated that the seeds planted by the initial inflation of the universe were fostered by dark matter, but if there are no atoms to serve as material, those seeds won’t grow. But when the universe was first born, there were no atoms, and when matter was created, antimatter was created along with it—and when both are left in this 1-to-1 relation, the matter and antimatter will cease to exist.” But if matter and antimatter cancel each other out, then the universe should be empty. Which leads one to ask: why are we living and breathing here now? Professor Murayama says:

“I believe that slightly disrupting the balance between matter and antimatter leaves a very small asymmetry and the remaining asymmetry is us. Well, then, how was this asymmetry created? That brings us to expectations for the neutrino. Research is progressing on using gravitational waves to investigate the mechanism that generates the asymmetry between matter and antimatter. Up until now, these things were thought to be absolutely unrelated; but now, there is a general feeling that these are possibly somehow connected.”

While trying to unlock a mystery, a connection is gradually starting to appear little by little, something like the relation between dinosaurs and elementary particles, and this awakens our endless curiosity.

Lastly, we would like to ask about the photon, which is one of the elementary particles—and the theme of this webpage. What can you tell us about photons?
“Well, the image I have of them is that they are white, small particles that turn round and round. They also give us a great deal of information.”
So, what kind of a role do they play?

“Well, say there is a galaxy some billions of light years away from us. Photons from that galaxy scatter in all directions. These photons travel for some billions of years and some of them even somehow make it to our planet. And that alone is a miracle in itself.”

“Thanks to these photons, we can view the state of faraway galaxies. In fact, taking a close look reveals various colors, and analyzing the makeup of those colors shows where, how many, and what elements there are—and how they behave and move. So these photons give us a terrific amount of diverse information.”

The photon is one of the elementary particles* in Professor Murayama’s specialized field and the real identity of light that is all around us. The electron is also one of the elementary particles. We humans live a “miraculous” existence, born on a planet called Earth in a solar system in a corner of the galaxy within a vast universe. Making use of light and electrons that miraculously reach our planet from somewhere in the same universe, we’re stuck to Earth’s surface and lead our lives as individuals carving out a 4.8 billion-year history along with diverse kinds of other living creatures. However, all of that is only a tiny fragment of the truth behind the universe. We still do not fully understand photons, other elementary particles, and dark matter and dark energy. Even the mind contains secrets of how it was born and how it works so wonderfully.

The famous words “The universe is written in the language of mathematics,” by Galileo Galilei, are inscribed on a pillar (obelisk) in Piazza Fujiwara at Kavli IPMU. Reading it seems to naturally make us think, “I want to know more about the world!” This is the inspiration we get from the life of Professor Murayama and the mission of Kavli IPMU.

* The following 17 types of elementary particles have been discovered or predicted by the Standard Model of particle physics