Cumrun Vafa on Stringing the Universe Together

02/10/2016 03:54 pm ET Updated Dec 06, 2017

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Credit: Hayward Photography

With the goal of harnessing the untapped potential of Iranian-Americans, and to build the capacity of the Iranian diaspora in effecting positive change in the U.S. and around the world, the West Asia Council has launched a series of interviews that explore the personal and professional backgrounds of prominent Iranian-Americans who have made seminal contributions to their fields of endeavour. We examine lives and journeys that have led to significant achievements in the worlds of science, technology, finance, medicine, law, the arts and numerous other endeavors. Our latest interviewee is Cumrun Vafa.

Cumrun Vafa is an Iranian-American physicist at Harvard University and one of the leading string theorists in the world. He has written over 250 scientific articles. He is well known for his joint work on developing a way to calculate black hole entropy and shedding light on some work of Stephen Hawking. He has been recognized globally for his numerous deep and groundbreaking contributions to quantum field theory, quantum gravity, string theory and geometry. Dr. Vafa is the recipient of numerous awards including the Dirac Medal, the American Mathematical Society's Eisenbud prize and American Physical Society's Dannie Heinemann prize for mathematical physics, and the Frontiers prize for fundamental physics. He was elected as a member of the National Academy of Sciences as well as the American Academy of Arts and Sciences. For more details, please click (here)

Can you tell us about your background? Can you outline your journey beginning as a high school student to your appointment as a professor at Harvard University?

I was born in Tehran in 1960 and went to Alborz High School, one of the most prestigious high schools in Iran. I came to the United States in 1977 to pursue my studies at the Massachusetts Institute of Technology. I did a double major in physics and mathematics. Then, I went to Princeton University where I did my Ph.D. in physics.

What brought you to the world of physics? Was there a particular person, place or event that you count among your key influences to date? Who has been your greatest mentor and why?

My interest in physics started with a deep curiosity about how things work. When I was in high school, I was impressed by the power of physics in predicting trajectory of projectiles. At the time it was very interesting for me but I did not see it as leading to a profession. When I came to the United States, in my freshman year, I became very interested in physics and math, much more so than the rest of my courses. My interest developed over a year. Newton and Einstein, as seminal figures in physics, had a huge influence on me. I decided in my sophomore year at MIT to double major in physics and math.

What is the value of scientific research? Do you think societies and governments around the world value it enough?

Different governments have different values. The U.S. government by and large highly appreciates science. That's part of the reason why the U.S. has many great scientific centers which are supported by the National Science Foundation. Unfortunately that hasn't been the case for many other counties. The United States has a long-term view of investing in science. Of course, we still need more support.

Your primary area of research is string theory by which physicists try to find a unified fundamental theory of nature. String theory provides a framework to unify everything we know about nature, including all particles and the forces between them, in a consistent quantum theory. Can you tell us about your contributions to this theory?

The subject started in the late 1960s, and has been developing ever since. I began studying string theory in 1984. I work on different aspects of string theory, and most of it has to do with finding and building models and solutions that describe our real world, including how particle interactions arise, understanding how the dynamics of black holes work, how cosmology works, and how the beginning of the universe emerged, so I have worked on many aspects of string theory. In '94, duality symmetries of string theory were discovered and I have been involved with the development of these ideas. I've also been interested in mathematical applications of string theory as well.

String theory requires a tremendous amount of mathematical technology. In fact, most of the mathematics needed for string theory has not yet been developed. Can you tell our readers about the mathematical aspects of string theory in an introductory way?

Physics and mathematics have had a long and deeply connected history. For example, one can see the connection between the development of Newtonian mechanics and the development of calculus. This connection has been developed over the centuries, such as in the 20th century when Einstein using advanced ideas about geometry to describe the general theory of relativity and how gravity works. Modern abstract ideas of mathematics have had enormous impact on the development of string theory. However, because the mathematics of string theory has not been fully developed yet, we use a lot of our physical intuition about how things should happen to guide our mathematical intuition. It is natural to expect that string theory involves a lot of mathematics, when you take into account that the dimension of space-time in string theory is not three space and one time; instead, we have more spatial dimensions, which are believed to be tiny and difficult to detect. The question then becomes how these extra dimensions, and handles and holes in them, translate to physical properties of the observed universe. String theoretic motivation has led to new mathematical questions about spaces and their properties. For example, this has involved understanding questions such as counting how many spheres fit in different spaces. These were among questions that geometricians were anxious to answer and couldn't, and the intuition from string theory has helped understanding answer to these kinds of questions.

You have authored and coauthored over 250 scientific articles, with more than 100 of those articles having been cited at least a 100 times. Can you share with us an exciting moment about a particular work you have been involved in?

In early 1970's, Stephen Hawking (building on an earlier work of Jacob Bekenstein) theorized that black holes should behave thermodynamically and in particular should radiate. Having thermodynamic properties implied that they should have microscopic states. However, he could not account for these states. In mid-1990's, jointly with my colleague Andrew Strominger, we found how to account for the microscopic states of black holes using string theoretic ideas. It was very exciting, because we had to get an exact match with Hawking's prediction, including factors of 2 and pi, and when we carefully included all factors, it was a perfect match with what Hawking's work anticipated.

What is the most satisfying aspect of your work?

The most satisfying aspect of the work is when I actually see connections between the different ideas that I have studied that had previously gone unnoticed. Sometimes I see two or three different ideas coming together, and in very unexpected ways. They fit together like different pieces of a jigsaw puzzle. Many times you would not expect them to fit, but somehow they fit together beautifully- those are some of the most satisfying experiences I have had. Of course, occasionally they also have mathematical applications, and that makes me even happier, to see these ideas in physics can find applications in math as well.

What do you hope to achieve by doing research in physics? Do you have a personal goal?

For me, the most beautiful aspects of physics are not the complicated math equations or even the ability of predicting how things will happen. What attracts me to physics is what it teaches us about the bigger picture. The general philosophical lessons that are embedded in physical laws are what excite me. For example, the fact that all particles and forces get unified within string theory teaches us about the unity underlying our universe. The amazingly vast collection of solutions to equations of string theory suggests that there may be many universes besides ours. What happened before the big bang, or was there a time before big bang? The "duality symmetry" in string theory, which exchanges small spaces with large spaces, suggests that perhaps as we go back in time the universe was effectively getting bigger instead of smaller. This suggests we came from other universes. Physics teaches us deep facts about our universe and our place in it. I hope I can add a little to this beautiful story. That is my goal.

What you would say to an undergraduate physics student unsure about where they are heading?

I would say follow what you're really interested in, and do not feel that you have to do a specific type of physics or science. Just see what is really interesting to you. We are lucky if our interests align with our abilities, and we should take this into account in deciding whether we wish to study physics or which area of physics we would like to work in. But as I said, the most important thing is to find one's true interest in the subject.

You are or have been involved in many of organizations in the Iranian-American community related to science, knowledge, and innovation. Why you are most passionate about the community and what do you believe the future holds?

Actually, I should make a slight correction, because I don't think I have been involved enough, and part of the reason is the kind of relationship that we have had between the United States and Iran, which hasn't made working at the intersection easy. So I would say that I have not been able to contribute as much as I would have liked to; I occasionally travel to Iran and talk to people there, but I really haven't done much in this regard, and I think many of us here would like to do much more than we have done to build a bridge between American scientists and Iranians and, hopefully, by the development of better political relations between the two countries. Perhaps we can realize this goal. Of course, we also have a number of Iranian scholars and scientists who come and study or do research in the US, and so I get to see and meet some of them, and hopefully this kind of back-and-forth and dialogue between Iranian and the American scientists will increase in the future as well.

You have said that throughout history, Iranians have been a powerful force in the development of human civilization and science. To some extent, is the Iranian culture and civilization a key factor in your success as scientist?

I think that every culture has in it a particular philosophy; whether we realize it or not, by the very fact that we have inherited a culture we carry much of it within us. What is crucial in science is to have been exposed to different viewpoints and the multi-cultural underpinning of their environment has been very helpful to scientific progress. Iranian culture is one of the oldest civilizations in the world. Like some of the deep cultures such as Indian or Chinese, Iranians hail from a very interesting and rich cultural heritage. So when I explore what Iranians bring to science, just like many of the other civilizations, we bring what our culture taught us, meaning that our cultural heritage has helped the development of scientific thought.

When an Iranian approaches a given problem in science, her viewpoints might be slightly different from somebody that comes from, say, a US culture, or Japanese culture, or French culture. There are different viewpoints, and bringing different viewpoints is always useful. Now, the very fact that in modern science Iranian scientists are under-represented means that there are few of us who bring that other new viewpoint, the viewpoint of the Iranian culture, into scientific discussions. And so in that sense I can bring a viewpoint which is kind of unique in many ways when I discuss some problem with my colleagues.

I'll just give you one example of this, but there are many similar ones. In our culture in Iran, we rarely believe in accidents, we always believe that things are designed in intricate, highly interconnected ways. This is reflected in our intricate structures in poetry. This is unlike many other cultures where things are very straightforward and accidents are assumed to be very typical. So in the context of discovering duality in string theory, what happens is that a lot of different parts of physics get connected in a very non-trivial way, and originally, many of my colleagues thought that these were just accidents, and the relations between different things were just part of an accidental feature of events.

From my background, I never viewed these as accidental. So my cultural heritage helped me in raising the question or becoming more aware of the possibility that these are not accidents, and that helped with many similar things. Of course, there are also aspects of my culture which are perhaps not helping me, and they may make me more likely to make mistakes sometimes. Diverse cultural viewpoints may be more helpful in some aspects of physics than others, I don't want to give the impression to you that Iranian culture is superior to other cultures. On the other hand, I think every culture brings a new viewpoint and we have to somehow bring diversity of approaches to viewpoints to bear on the questions of science. It is the duty of every person from their own culture not to forget the philosophical underpinning of their culture and bring it to bear on scientific questions.