Q&A with Frank Wilczek On Different Universes, String Theory, Gravitation, Newton & Big Bang
Physics Nobel Prize Winner MIT Professor Frank Wilczek on Different Universes, String Theory, Gravitation, Newton & Big Bang
RR: We’re going to learn from one of the greatest living scientists Professor Frank Wilczek, who won the 2004 Nobel prize in physics. Can you describe to our mainstream readers who are used to more simplistic things how you won this Nobel prize? It’s such an inspiring and amazing thing for me.
Frank Wilczek: The subject of the Nobel Prize was figuring out one of the fundamental forces of nature theoretically. With our current understanding, we have four fundamental forces. Gravity and electromagnetism, which are classical forces that have been known for a long time and have had beautiful theories for a long time in the case of gravity. Going back to Newton and then in the 17th century, it’s a fantastically beautiful theory by Einstein and general relativity in the early part of the 20th century. In the case of electrodynamics, it all came together in the middle of the 19th century. At the beginning of the 20th century when physicists were exploring the subatomic world, they discovered that those two forces were not enough. We needed additional forces to explain what was going on inside atomic nuclei, so one kind of force was needed to explain what holds the nuclei together that’s called the strong force.
RR: Before any further explanations, professor. Could you, just for our readers, help explain how Sir Isaac Newton kind of ropes into this as well?
Frank Wilczek: Well, Sir Isaac Newton provided, in the 17th century, a very elegant mathematical description of gravitation–famous law, “the force equals a constant times the product of the masses involved divided by the radius between them squared.” That was a model for precision power as a universal law that, together with his framework, the laws of motion classical mechanics, made a revolution and in understanding the motion of planets and the motion of tides here on earth,. Among many other things, it provided a model of what scientific understanding should be: precise, universal, and quantifiable.
But, in particular, it explained that one of the basic interior forces of nature, gravity, dominates the motion of celestial bodies. One measure of the power of his achievement is that, RRter his work, the predictions were very precise. It was just a matter of how well you can solve the equations, and the observations got more and more precise as time went on. That simple law held up for many decades.
There seemed to be, at one point, a tiny discrepancy in the motion of Uranus. That was a kind of dark matter problem at the time. There was an unexplained deviation or not something was gravitating that shouldn’t be. That was something that was contributing to the celestial motion which had no apparent source.
But this led people to postulate the existence of an additional planet. Because of the present, they could use the law of gravity to figure out where the planet would have to be in order to explain this discrepancy. Sure enough, Neptune showed up as a result. That was a model of what a physical law could be. And did you know anything about it? You write down this equation and it describes the cosmos in such detail that you can start to worry about tiny deviations from between the predictions and what you observe at the level of a fraction of a degree up in the sky.
That led to the discovery of new planets in the 19th century. People started to understand electricity and magnetism, which are big forces here on earth, and that was all ultimately put together in the middle of the 19th century by Maxwell in the so-called Maxwell equations. As a result, once again, they’re very precise equations. They’re more complex than Newton’s law of gravity, but very beautiful when you build up the machinery to the intellectual machinery to understand them. And also extremely fruitful: all of modern radio technology and electromagnetic communication comes out of the Maxwell equations. Those are still used in electrical engineering everywhere.
Among one aspect of that achievement was that light was understood: visible light, which used to be a thing in itself not connected to the other parts of physics, turned out to be a disturbance in electrical and magnetic fields. Light is understood as a disturbance in electricity and magnitude of the great unification, a marvelous example of what you could achieve through theoretical insight and in understanding the world.
The story is that we wanted to have equations that were worthy of standing beside those equations–the pinnacles of physics describing fundamental forces–also for these new forces, for the strong and weak forces. To make a long story short, we were able to discover the equations for the strong force.
RR: From what I understand, the technical matter of your Nobel Prize is that particles change their interactions as they heat it up. Is that correct, or am I misunderstanding?
Frank Wilczek: Well, that’s one aspect of the theory. It turned out to be the key to cracking the description of the strong interaction and enabled us to find the correct equations. I mean, if you think about it, whereas with electricity and magnetism you could work with laboratory-sized objects and in gravity you could look up at the sky and see, and it’s much more difficult to study subatomic processes and so finding the laws was a very tricky endeavor and dominated 20th-century physics for a long time.
When we figured it out, our discovery was highly leveraged, but a lot of other people had done in finding aspects of the strong force and trying to infer from very indirect clues what the basic description might be. But the phenomenon, the experimental phenomenon that turned out to be crucial is the fact that the basic particles of the strong interaction are something called quarks. You could infer very funny aspects about the force between them, namely that it got weak at high energies or at short distances which is something that is very difficult to achieve in a way that’s consistent with the principles of quantum mechanics and relativity. So what we did was show that when you use that basic fact together with the principles of quantum mechanics and relativity, you were led to a pretty unique proposal for what the equation should be. That proposal and those equations were capable of supporting other deductions, experiments that hadn’t been done yet, and it works!
RR: Was there a hardship for you?
Frank Wilczek: Well, there were several. The first thing to find was why did this peculiar behavior — that was built up in a way that was consistent with the principles of quantum mechanics and relativity — exhibit the phenomenon that forces get weaker at short distances. Most forces get stronger at short distances. . Finding quantum fields that have that kind of behavior was very difficult and led us to a very unique proposal for what the equation should be, which turned out to be right.
RR: Einstein said he came up with 999 ways to not make a light bulb. Would you say that applied to your work or not well?
Frank Wilczek: There are an infinite number of ways of not doing it, and there’s only one way to do it. I guess that was the gift from heaven. That is very unusual. So this apparently arcane experimental fact that was produced from very indirect clues, cracked open the whole problem. It is a miracle that from that one clue you could figure out everything if you thought about it hard.
RR: You mentioned “heaven.” Newton felt that there was a God because the laws of physics were so beautiful and intricate. It’s just interesting to note that Newton did express this sentiment because the laws were so specifically intricate, and that there must be someone who created those laws.
Frank Wilczek: Well, Newton was religious, independent of science. I would say he spent a lot of his life in fact in biblical studies, probably as much as he did in science. But he didn’t see a conflict between them. He thought that by studying the physical world, he was uncovering God’s plan in a very literal way. He was a great, honest scientist. He took the world as it came, but he had full confidence and full faith that science would be a revelation of how God worked because he was very much a student of the Bible, and a very much a believing Christian.
RR: Where is the border between math and physics given that theory offers a huge number of possible universes instead of just one?
Frank Wilczek: OK, so I think what you’re alluding to there is that the quest for the unification of the four force laws. In particular, a way of reconciling the basic principles of general relativity (the theory of gravity) with quantum mechanics has proved to be very difficult. The most promising proposal so far is called string theory, but it’s still got a lot of problems. We don’t really have a proper definition of string theory, and we don’t have the tools to draw out its empirical consequences in a convincing way. But what seems to be emerging is that the equations and understanding as we have them allow many solutions that correspond to different possible realizations of the fundamental laws. The truly fundamental laws, at the level of practically fundamental laws, are mostly discussed under the concept of the “multiverse.” It’s the idea that although the underlying equations are in common, distant parts of the universe might have extremely different physical behavior. For instance, the number of spatial dimensions (the number of large spatial dimensions that you could move around in) might be different in different regions far away. Instead of being three, as it is in our neighborhood, it might be five, two, or one.
RR: So there are different universes?
Frank Wilczek: Yeah, very different universes. There might be universes in which there’s no electromagnetic force, or distant parts of the universe in which there’s a much different amount of dark matter, but those are very different behaviors, and that leads to the question: well, if there are all these possibilities, how do we predict or how don’t we lose the power to predict what the form of the laws is? In effect, one of the grand goals of unification was to explain why we have the forces we do and no others, and why we have to really get an enhancement of our existing understanding, rather than kind of saying well a lot of it is just random, accidental, and it’s different elsewhere, and you’ll never figure it out because you can’t. So, the richness… that’s a kind of disturbing situation that I hope is temporary. There’s a kind of mismatch between the theoretical development, which is very rich in mathematics and mathematical potential, and is proved so very entertaining to a lot of professional mathematicians, who use the methods that physicists are developing to try to understand this theory.
RR: How will spatial exploration — space and software —- impact the future for theoretical physics?
Frank Wilczek: Yea, it seems like a long shot, but it’s certainly not in the sense of space exploration by humans. I mean, space exploration by telescopes and astronomical observations so far have not revealed this potential behavior that distant regions could behave very differently. In fact, quite the contrary, it’s a really profound aspect of what we know about the universe or the part that we’ve surveyed, is that you have a view in the beginning, or the same laws hold everywhere. The same laws seem to hold everywhere very precisely and consistently.
There are many, many compelling lines of argument and pieces of evidence that the universe which was much denser, much hotter, and much more uniform —- actually kind of a featureless hot uniform gas that expanded, going towards us, and parts of it contracted, collapsed gravitationally into the galaxies, planets, stars, and so forth. But the beginning was very hot, dense, and uniform — that’s what we call the Big Bang. We can trace that, I think convincingly, using the equations we have down to small fractions of a second past a time when the equations break down. If we keep extrapolating all the way back to determine a kind of zero of time when everything was not only very dense but infinitely dense, then the equations break down. But if we start from extremely dense and just run for a small fraction of a second, then the equations work and give convincing consequences, and our understanding of QCD and asymptotic freedom played a big role in that because the fact that the strong interaction turns off at high energies was what enabled us to understand what the very earliest moments might be like. But when we go back to the very beginning, then we don’t know — our equations break down. So, one of the hopes for a unified theory — also that brings in gravity — is that we can get a convincing description that doesn’t have this breakdown of the equations at the very beginning.
RR: Speaking to you as a student of philosophy if time is constant, isn’t there really no beginning then? That there isn’t the idea of the beginning in itself in essence?
Frank Wilczek: Well, I don’t think it’s logically inconsistent to imagine that the physical world was so different or earlier in its history that, that you know, passed a certain point, that is not useful to talk about what was happening then. Or so there was a singular moment in the history of the universe from which we can understand it in the kind of terms we use to discuss events today. In many ways to me, but your question is a very interesting one. This goes back, I think, some of the wisest things about this were said by Saint Augustine. He was asked by permission by a parishioner, what was God doing before he created the universe? And Augustine’s first answer that he said occurred to him was that he was preparing hell for people who ask questions like that. OK, but then he, but the question modded him, and he wanted to give her a proper answer because it was a profound question. And he gave, I think, a very profound answer which I think in some form will probably be the answer to this question that gets established by science. He got into a deep meditation on the nature of time, which is in book 11 of his confessions. And although he certainly didn’t put it this way, I think a fair summary of this conclusion of the argument is that he decided that after thinking about it very hard and looking at what people actually mean when they talk about time. He said, “Time is what clocks measure. Time is something we understand in our minds.”
RR: It was a made-up idea?
Frank Wilczek: Yeah, time is a construct, it’s an abstraction from the behavior that we see in clocks but also in other things; everything that changes in the same direction or changes according to a universal quantity, a universal flow that we call time. That’s the way we can dance together, we can sing today, we can agree on what time is and practice. But he said that there has to be something to measure time; it does not exist as an abstract thing outside of its embodiment in physical objects. So, his answer then to the question of what was happening before God created the universe was that since there were no clocks, and nothing to measure time, there was no time. And so, asking about what happened before that seems to be a grammatically sensible question, actually does not correspond to a physically meaningful question. It’s kind of, the words are misleading.
So I think that’s going to be the ultimate explanation. But I might be wrong, it might mean there are other ideas about cyclic universes. That the equations break down, the universe collapses, things get very dense, equations break down, and we can’t really predict what happens. But what happens is that it bounces and makes the next fanning universe, which is the phase we’re living in now.
So there are certainly different speculations, but we don’t know and we can’t decide between these speculations at present.
RR: Referring back to your work, did string theory or QCD succeed in explaining the work environment ?
Frank Wilczek: Well, QCD certainly did. QCD is something we can program precisely on a computer and work out the consequences of the equations of QCD that are very precise equations. Yeah, be more complicated, and it’s fair to say vastly more complicated than Newton’s law of gravity which we just mentioned earlier, but similar in spirit and in their precision. And you can tell a computer precisely what to do to calculate their consequences, and modern computers can solve them in a number of ways. They can do a pretty good job of solving them to answer questions like, “Do quarks exist as free particles?” And the answer is no, the equations of QCD give you exactly the particles that we observe, no more and no less. So, QCD solves the problem. A string theory initially was before it became a theory of quantum gravity or potentially a theory of everything, people advertised it was originally invented to be a theory about what we call strongly interacting particles. And it sort of has built in as an assumption when the confinement of quarks because it’s built out of ingredients that don’t include quarks. But that approach to understanding strong interaction really never worked. Now, there are sort of attempts to understand QCD using the tools of string theory, and they’ve had some modest success.
RR: But these tools and or analytical methods or is there any future for analytical methods or is it all simulation at this point?
Frank Wilczek: Well, I mean there’s a future in the sense that people will have fun doing it and maybe something useful will come out. I think the prospect of replacing computer calculations with fully analytic calculations (analytic meaning things that people can sit down and write out by hand, one or a few people, like medieval monks doing calculations by hand) is logically conceivable but I would bet large amounts of money against it in the foreseeable future.
What I think could very well happen and probably will happen–it would be a great thing–is a kind of partnership between computers and humans to build on the strengths of each, to combine heavy-duty calculations with approximation schemes that tell so that the computer doesn’t have to start from scratch, so to speak. In this way, people can use intermediate models, like in chemistry, where people never use quarks, and then they use intermediate models. I think there’s a future in understanding nuclear physics at that level, which will be based on the equations of QCD but will use intermediate concepts, and the concepts will be invented by humans but implemented in computer programs. There’ll be a kind of partnership. I think that’s the way science is developing in many areas these days, and I think the partnership between man and machine is the future of a lot of areas of science.
RR: Speaking of the future, I absolutely loved reading your book and I really want all of our readers to read it. It was just so much fun, and such an exciting read. The Lightness Of Being – By Frank Wilczek (paperback)
Frank Wilczek: Yes, I really enjoyed writing it. When I first made the proposal, I thought of it as a chore to convey things to the public and answer my friend’s questions about what I do and how we understand the world now. As I wrote, it was really a joy because I’ve revisited the kinds of questions that I had as a teenager that kind of got me interested in science in the first place. I really came at it from philosophy really, and even religion, and while I ceased to believe in the dogmas that I was exposed to, it kind of left a hole. I mean, what does it all mean? What is the secret message? What is the message of the physical world? It’s a wonderful intellectual walk and it turns out that I reengaged with those questions. I’m glad some of that comes through.
RR: Well, our last question of the day is what unsolved mystery, what question and science would you like to see solved?
Frank Wilczek: Well, I’ll let me give you first of all a personal perspective, and then I’ll give sort of a more expansive perspective. First of all, there’s a great problem of physics and cosmology, which is what dark matter is. Astronomers have discovered that there’s a lot of stuff in the universe, it’s about five times as much or six times as much as the stuff we understand by mass. There’s an additional component of the mass of the universe that is not made out of the quarks and gluons and photons and electrons and things you’ve understood very well, and nobody knows what it is. But I think I know what it is. I think it’s something called axions, and we’re just now developing technologies that are capable of detecting this dark matter (if it is axions). That’s certainly a great challenge and opportunity to either prove itself or prove it’s not.
So, another area that comes dear to my heart, since it comes out of things that I’ve worked on a lot and pioneered, is the prospect of so-called topological quantum computing. This uses the properties of emerging particles called anions that can exist inside materials that have a kind of memory. This was a proposal that dates back about 40 years, but only in the last few months has been convincingly demonstrated. People think technology is such that it’s plausible that you can build on it towards making actual working quantum computers, and I’d love to see that. That would open many doors.
There’s also time crystals, which I think could lead to more accurate clocks and having other applications. There’s a new state of matter that can, so-called time crystals; We don’t really know exactly what they’re good for, but it’s very exciting to see this. So, I’d like to see what are the potentials of that. Those are my three “babies” now, which are currently maturing, and I’d like to see what happens to them. Those are frontiers that are personally very exciting to me but also to many of my colleagues. To me, the greatest problem on the horizon is understanding how the mind emerges from matter. I think now our understanding of what matter is; is good enough. It’s really bad that there’s nowhere to hide if you believe in what Francis Crick called the “astonishing hypothesis”: which is basically that the mind emerges from matter. If we have to prove it, technologies are becoming available to do that. Progress is being made, but I think the greatest work there is going to come and it’s especially exciting and rich and fertile because we’re understanding how our minds work, how human brains work, and part of the same process is understanding how the minds we’re creating work.
We have these artificial minds that are becoming more and more powerful, more and more general in their intelligence — more human if you like — and how do we relate to those? How do we understand their minds, which are clearly based in matter because we’ve designed them to understand matter. And then there are going to be new kinds of vibes, quantum binds, new kinds of quantum computers that are really qualitatively different from existing kinds of computers and existing kinds of minds. And what are those gonna be like? What is going to be a psychology course, and how will they influence factors? What’s the wealth? A narrow question is how do we make use of them to design better drugs and do chemistry better, and really exploit the full control of nature that, in principle, we have since we know the equations. But I think more than that, it’s famously difficult for people to understand how quantum mechanics works intuitively. Our minds are not well adapted to that. That’s not how we do it. Evolution did not prepare us for it. And when we learn as babies, we construct a very different model of the world. So it’s very difficult to visualize the thought processes of things that are really quantum mechanical intelligences. Again, work for the future that will be really fascinating to figure out, because it is sort of the psychology of quantum computers.
RR: Thank you for sharing your time Professor — you’re a living legend!
Frank Wilczek: Thank you very much!
Edited by Avhan Misra // Rebellion Research