Meet Paul Steinhardt, Ph.D.

Paul Steinhardt discussed two of his many research accomplishments on SftPublic's Contemporary Science April 30, 2013 Two Paul Steinhardt Projects.

Due to time constraints the night of Dr. Steinhardt's appearance on Contemporary Science, we were unable to videotape a bio clip. However, Dr. Steinhardt very kindly answered questions in writing, so click here Bio-Questions for Dr. Steinhardt or scroll down this page to learn how he got into physics, and how he has maintained his comprehensive perspective and his intellectual independence. And some interesting reflections.


Professor Steinhardt is the Albert Einstein Professor of Science at Princeton University and a professor of theoretical physics. He is on the faculty of both the Department of Physics and the Department of Astrophysical Sciences, and is the Director of the Princeton Center for Theoretical Science. Dr. Steinhardt received his Ph.D. in Physics at Harvard University. He was a Junior Fellow in the Harvard Society of Fellows and Mary Amanda Wood Professor of Physics at the University of Pennsylvania before joining the faculty at Princeton University in 1998.

Although his expertise extends across several areas of theoretical physics, Professor Steinhardt is best known for his work in theoretical cosmology. He played a major role in further developing Alan Guth's inflationary model, a model that attempts to explain the homogeneity and geometry of the universe and the origin of the fluctuations that seeded the formation of galaxies and large-scale structure of the universe.

Dr. Steinhardt introduced the concept of quintessence, a time-varying form of dark energy to explain the current accelerating expansion of the universe. With colleague Neil Turok, he addressed problems of the inflationary model by developing an alternative, the cyclic model of the universe. He discussed the cyclic and inflationary models of the universe in his April 30 discussion.

Paul Steinhardt's work in condensed matter physics with Dov Levine led to a theoretical speculation of the quasicrystal, a novel phase of matter which has symmetries forbidden to ordinary periodic crystals. He ended up actually locating an authentic example of the improbable quasicrystal. He has made numerous contributions to understanding their mathematical and physical properties. Recently, he has helped develop a photonic quasicrystal (the quasicrystal analogue of a photonic crystal) for efficiently trapping and manipulating light in selected wavebands.

Professor Steinhardt is a Fellow in the American Physical Society and a member of the National Academy of Sciences. He shared the P.A.M. Dirac Medal from the International Centre for Theoretical Physics in 2002 for his contributions to inflationary cosmology and the 2010 Oliver Buckley Prize from the American Physical Society for his work on quasicrystals. In 2012 he received the John Scott Award for developing the theory of quasicrystals and discovering the first natural quasicrystals. In the same year he was also named Simons Fellow in Theoretical Physics, Radcliffe Institute Fellow at Harvard; and Moore Fellow at Caltech.

Dr. Steinhardt is the author of over 200 refereed articles, six patents, two patents pending, three technical books, numerous popular articles. He is co-author (with Neil Turok, 2007) of an acclaimed book for a general audience, Endless Universe: The Big Bang and Beyond, which discusses contemporary theories of cosmology, including the cyclic universe. He has lectured widely on his decades-long pursuit and ultimate co-discovery of the first natural quasicrystal.

Bio-Qs for Paul Steinhardt

Q: Were there any early indications in childhood that you would be drawn to physics?

ANSWER:I was always drawn to science. My two goals in life beginning at age three was either to become a cowboy or a scientist. What attracted me about science was discovering something new. The thought that you could discover genuinely new things seemed amazing; by adding to human knowledge in this way, it seemed like the most lasting contribution to human history one could make. As a youth, I had biology and chemistry labs at home, and I would take out the telescope regularly; I followed NASA and space missions very closely, keeping my own logs. I also did science fair projects (in mathematics). But, physics did not appeal to me at all; with the exception of one three-week summer experience, my worst teachers in high school were my physics teachers. I had a vague feeling the subject might be better than it seemed; so I chose to go to Caltech for college in part because they force you to take two years of physics. That turned out to be a fortuitous choice. My first year teacher at Caltech (Prof. Tommy Lauritsen) and the presence of Richard Feynman on campus changed my view of physics in a matter of a month, and I never looked back.

Q: You got into physics at a very exciting time. Can you describe has been most exciting –or, alternatively, frustrating—for you?

ANSWER:There are too many exciting ideas and discoveries to mention. One of the more amazing developments has been to see how cosmology has evolved from a field with little data dominated by metaphysical ideas into a hard science full of data and with tight connections to fundamental physics.

Q: Your perspective of reality/nature is probably quite different from that of non-physicists (even scientists in biological and other fields). What is distinct about your reality?

ANSWER:Physics suggests that the nature is comprehensible and ultimately derives from a few basic principles. So perhaps what is most distinct is that I see common everyday experiences as employing the same principles as those that shaped the entire universe and I am always looking for puzzles and surprises that may reveal those principles.

Q: You are unique in that you are able to do very deep-level work in several different fields. At one time, it was much easier for a single mental giant to master several different fields; but today scientists are frequently so specialized that they have difficulty even with sub-specializations in their respective fields. Can you describe how you manage to maintain expertise —and leadership—in multiple areas of physics that (to outsiders) do not seem closely related?

ANSWER:I cannot give a formula for doing this. I was drawn to science by curiosity, and this curiosity always extended to all of science, not just one discipline or subdiscipline. In grad school, I knew that I had to focus for a period in order to learn how to do high level, professional research. Throughout, I made a point of attending lectures and seminars in a variety of fields, but I did not have time to pursue them. The moment I received my PhD, though, I immediately began to explore diverse problems, letting my curiosity roam. I realized (and was told repeatedly in case I didn't) that this was tremendously disadvantageous if I wanted to be successful; and, indeed, this spreading out did mean I was less productive in any one field than the typical; and it did make it difficult to progress career-wise. But I always figured I would pursue science my way or not at all. What I did not appreciate was that crossing disciplinary boundaries constantly gives you access to people and ideas that most people who remain in any one discipline do not get, and this is tremendously advantageous. The best ideas come from lectures or conversations with people in one field that suddenly inspire ideas in another. If I were only listening to lectures in the one field that everyone else was listening to, then I would lose this advantage. On the other hand, it takes a certain kind of discipline, perhaps a certain dose of insomnia, and a certain degree of fearlessness or foolishness, depending on your perspective.

Q: You have been a genuine pioneer in at least two areas of physics, and in an era when many scientists try to avoid bucking whatever the trend is in their fields. What is it like struggle against the grain, and what sustains you?

ANSWER:To be honest, it is tough and rough. In some of the areas in which I work, people work so hard to avoid bucking the trend that they not only blind themselves to obvious problems, but they are quite aggressive in trying to knock you down if you point the problems out to them, even when they are quite obvious. The growth of big science, big projects, and big theoretical networks working on common idea encourages group-think and overpopulates the field with people who are not willing to question authority assumptions. It is a very unhealthy situation. Fortunately, I am just not deterred by this. Quite the opposite, if everyone is going one way, I think it leaves the opportunity for really great discoveries if you are willing to go the other.

Q: What should people know about theoretical physics?

ANSWER:Theoretical physicists play two important roles. First, they are the dreamers who question our assumptions and imagine possibilities that have not yet been observed or tested. More often than not, they are where breakthroughs begin, ultimately motivating new kinds of experiment and observations which, in turn, lead to new technologies. Second, they are gadflies that are more easily able to move from one subfield to another carrying information and ideas with them. (Experimentalists have difficulty finding time outside having to build and manage their laboratories and the scientists who work under them.) A mix of theorists and experimentalists interacting frequently is ideal for producing the most science.

The second point I would like to make is that, while our techniques are highly mathematical and difficult for the public to appreciate, the best ideas are usually simple and definitely comprehensible. So the public should seek, expect and demand clear explanations from theoretical physicists of what they are doing. If they cannot give them, it is not a deficiency on the part of the public, but on the part of the theorist.

Related to that is a third point: sometimes the public knows better than the theoretical physicist. I am thinking specifically of what is happening in cosmology at the present time. The inflationary theory is the most widely accepted explanation of the universe, yet it is well established that it produces multiverse in which literally, "anything that can happen and will happen an infinite number of times" with no way within the theory of deciding which outcome is more probable. As we discussed, this means that the theory makes no predictions. Proponents of the theory have adopted the view that the multiverse is marvelous because it makes the theory unfalsiable. When I raise this with the public, I find almost no one sees this as an advantage. In fact, since the public is funding the research, they might rightfully ask for their money back when it comes to people who support an untestable `scientific' theory.

Q: Do you think the gap between scientific knowledge and public ability to digest such information is increasing or not?

ANSWER: Actually, I am optimistic that the gap will be decreasing due to the availability of so much information on the internet and direct access to scientists through blogs, emails, and the like. I also believe firmly that all good ideas are simple; so where gaps are growing, it means the scientists are either off-track or are not doing their job to make the ideas comprehensible.

Q: There is a strong trend (at least in USA) of simplifying complex scientific material. Scientists are cautioned to avoid equations, etc in popular books, and many science documentaries (American) employ gimmicks. For the kind of information you want to convey, how well does simplification work —do you lose a lot of the substance in simplifying, or is it ok?

ANSWER:As mentioned above, I think all good ideas are simple and can be explained for the most part, without equations — other than very simple relations like distance = rate x time or force = mass x acceleration. That does not mean the audience does not have to think. New ideas are new because they have not been part of our education or experience before. But I do not think complicated explanations or complicated equations are needed — I think that usually means the communicator does not understand their subject well enough to extract the essence of it.

Q: Given the centrality of science in modern culture and the volume of scientific information we get, what kind of mental equipment do you think we need to participate in today's global culture?

ANSWER:I think what is inside our skull is still pretty good equipment. Our brain is remarkably good at filtering out unimportant information, recognizing patterns and asking challenging questions. We need to make some adjustment (which we all doing de facto). It used to be that getting access to information was a difficult challenge — getting to the best libraries, finding the best books, accessing the best authorities. So information seeking was a big task. We are now in the opposite limit where the information is there for everyone to use. The challenge now is filtering to find the essence or the key thing that does not fit.