01/08/2021

Finding New Particles On The Frontier of Physics

17:16 minutes

As a theoretical physicist, Frank Wilczek has made a career out of dreaming up new ways to understand our physical universe—and he’s usually right. 

In the early 1980’s, he predicted the existence of a new quasiparticle, called the anyon—which was confirmed in experiments last summer. In 2004, Wilczek was awarded the Nobel Prize in Physics for his contribution decades earlier to the theory of quantum chromodynamics. And in addition to the anyon, he has predicted the existence of a hypothetical particle known as the axion, a possible component of cold dark matter. 

Wilczek joins Ira for a sweeping, mind-bending conversation about physics and the universe as discussed in his latest book, Fundamentals: Ten Keys to Reality. Read an excerpt of Wilczek’s new book.


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Segment Guests

Frank Wilczek

Frank Wilczek is a 2004 Nobel Laureate in Physics and author of Fundamentals: Ten Keys to Reality (Penguin Press, 2021). He’s also the Herman Feshbach Professor of Physics at the Massachusetts Institute of Technology in Cambridge Massachusetts.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow. In 1982, theoretical physicist Frank Wilczek predicted the existence of a new quasiparticle, the anyone. And last summer came news that scientists have finally found evidence of it. As a theoretical physicist, Wilczek has made a career out of dreaming up new ways to understand our physical universe and being right about them. In 2004, Wilczek was awarded the Nobel Prize in physics for his contribution decades earlier to the theory of quantum chromodynamics.

And in addition to the anyon, he has predicted the existence of a hypothetical particle, the axion, a possible component of cold dark matter. Doctor Frank Wilczek is the Herman Feshbach professor of physics at MIT, and author of the new book, Fundamentals, 10 Keys to Reality. Doctor Wilczek, welcome back to Science Friday

FRANK WILCZEK: It’s wonderful to be here.

IRA FLATOW: In your career, as I mentioned, you predicted some of these things decades ago, in the 70s and the 80s, that only now are getting proven by experimental physics. In fact, there were two experiments last year that proved the existence of the anyon particle. What is the anyon?

FRANK WILCZEK: OK, so for many years, people thought that there were two kinds of particles that were two families of particles, i call them kingdoms of particles that were possible. And these are called bosons and fermions, and photons are examples of bosons, bosons like to do the same thing. That’s why you can have lasers where photons are all of the same color and moving in the same direction. And fermions refuse to do the same thing. And that’s largely responsible for the hardness of matter, the periodic table, and the existence of white dwarfs and neutron stars.

But when I looked at the so-called proofs that those were the only two possibilities, I was not convinced. And thinking it through, I realized that the proof worked if you assume we live in a space of three dimensions. And if you had a world of two dimensions, there were additional possibilities. This third kingdom is much more various than bosons and fermions, in principle. And it’s called anyons. Anyons are particles, quasiparticle particles, so they’re emergent concentrations of energy that basically have a kind of memory. They are a much richer kind of behavior, quantum mechanically, than bosons or fermions.

And in fact, there are elaborate plans on the drawing board to use these memories in quantum computers. But clear experimental demonstration came, for the first time, only last spring and summer in two very beautiful experiments.

IRA FLATOW: Could there be particles that we don’t know about? Because you know, we have all of this dark energy and dark matter. And it makes up 95% of the universe.

FRANK WILCZEK: Oh, for sure. Oh, for sure, there could be additional particles that interact very weakly with the particles that we use in biology, chemistry, and engineering. So that’s definitely true. And in fact, I think it is true that the axion that you mentioned earlier I think is very likely to be dark matter. And one of the things I’m most actively involved in now is trying to design axion antennas. And it’s not only me, it’s thousands of people now are hot on the trail of axions, using the equations to think of different kinds of antenna designs, different kinds of receivers, different kinds of observatories that’ll be capable of detecting this very, very weakly interacting but all pervasive cosmic medium.

IRA FLATOW: Gravity still remains difficult to unite with the other forces of nature in terms of quantum mechanics, right? There’s supposedly the existence of a graviton. Do you have to detect a graviton also?

FRANK WILCZEK: Well, no one has. It’s very challenging. And that’s known. And you face the same kind of problem. You know what the equations are and you can sort of gauge the difficulty of it and try to make detectors that would be sensitive to gravitons. I’m cautiously optimistic about that. It’s very, very difficult. LIGO for instance, is not detecting distinct effects of single gravitons, but only, sort of, the integrated effect of many gravitons acting together.

To distinguish that they really come in discrete units seems to be very difficult, but not impossible, I would say. And that’s one of the envelopes I’m trying to push now.

IRA FLATOW: You spend a lot of time in your book talking about artificial intelligence, its relationship to human beings.

FRANK WILCZEK: I think mind is an important frontier of physics in several ways. One is that now that we have such a secure powerful knowledge of ordinary matter, how it works, high on the agenda becomes either fulfilling or disproving what Francis Crick called the astonishing hypothesis that mind emerges from matter, that the human mind really is a phenomenon of the matter that makes the human brain that we should understand in molecular terms.

And nowadays, also, to understand certain parts of physics, the human brains need a lot of help. So the way we really solve the equations in powerful ways are to turn them over to computers. So if we just had to rely on human brains, our understanding of how protons are made, or how events emerge at the LHC with all their structure, for instance, it would be totally impractical. It’s beyond human abilities.

So the relationship of mind, and information, and physics is getting closer, and closer, and more complicated. And to me, the depth of it is, well, it’s unfathomable. And we’re getting down into it now in a totally new way.

IRA FLATOW: Do you have any fear that we might approach something called the singularity, the point in which artificial intelligence becomes more intelligent and people basically work for the AI?

FRANK WILCZEK: Well, I do think that the advantages of artificial intelligence over, let’s call it biological or natural intelligence, are so profound that, in the long run, the vanguard of mind will certainly not be unaided human brains. In fact, it already really isn’t. The best human brains get a lot of help from computers, cyborgs or maybe even autonomous artificial intelligence is eventually. But I don’t think it’s going to be a singularity. I think it’s not going to happen, one night you go to bed and you’re a computer is kind of dopey, and the next morning you find that it’s telling you what to do and turning you off or something.

I think there’s going to be a more of what we would call a crossover in physics, a gradual enrichment. I like the concept of an ecology of intelligence where there will be different kinds of minds that relate to one another, and learn about each other, and co-evolve.

IRA FLATOW: In the book, you take time to point out to dangers on our planet, climate change and nuclear weaponry. And you say these dangers can be avoided. Why did you feel it necessary to take this side trip?

FRANK WILCZEK: Because those are dangers that originate from deep understanding of the physical world. Nuclear weapons, of course, emerged from deep understanding of sub-nuclear physics. And climate change is a consequence of the industrial processes that science allows you to produce. It never hurts to remind people about that. And if you’re thinking about the future, which I try to make a point of in the books, I think it’s really important to think about, part of the future is making sure that there is a future or what could go wrong.

IRA FLATOW: Going back to the preface of your book, you say that writing this book changed my perception of the world. How so?

FRANK WILCZEK: Yeah, well, as I was writing the book, I had a grandson. And I watched how he was constructing the world. Babies, at first, they don’t even know there’s a world of objects out there. They see these raw impressions on their retina and have a lot of work to do to start to interpret those signals from the external world as distributions of objects in space with more or less reproducible or predictable behavior, and so forth.

So as I was thinking about– I was writing a book that I wanted to help people explore their reality and get the deep insights and the wonderful insights, the mind-expanding insights, that fundamental understanding can give. I was inspired to the idea that it’s a process of being born again, that now baby constructs a world model based on the local environment here on Earth, which is, in the universe, very rare and kind of limited.

That’s very untypical and not the deepest layer of understanding that we attain when we start to inquire using microscopes, and telescopes, and spectrometers, and accelerometers, and magnetometers, and all the instruments that science brings to bear on the study of reality, and of course, also logical thinking and critical thinking. So the concept of being born again came alive for me.

IRA FLATOW: You also write that in studying how the world works, we are studying how God works, and thereby learning what God is. Do you think physics reveals God?

FRANK WILCZEK: God is a word that’s used with many, many different meanings. It struck me also in this book and earlier investigations throughout my career in the history of physics that the scientific heroes like Galileo, Kepler, Newton, Maxwell, Faraday, all of them were deeply religious people. And Einstein, in a different way, he was not adherent of any conventional religion, but he talked freely of being an admirer of Spinoza, and I guess you could say a kind of pantheist that believed in the harmony of the world.

And so I think all of those people had a similar attitude. I’d like to think that they had a similar attitude to what I have, which is that one way of getting to the kinds of questions that religion addresses and the kinds of feelings it inspires is to examine how the world works and understand it deeply to understand what God is, that God is revealed through his, or its, or her work. And I think there’s no more convincing way.

IRA FLATOW: I’m Ira Flatow. And this is Science Friday from WNYC Studios. I’m talking with Nobel Laureate Frank Wilczek about his new book, Fundamentals, 10 Keys to Reality. I want to move on to the Big Bang. You talk about the different ways of determining what had happened and what it was like. How do we know what occurred almost 14 billion years ago, what we call the Big Bang?

FRANK WILCZEK: Well, it’s very much like how you reconstruct a crime. But usually you look for telltale clues of what happened, you found there’s blood, or DNA, or some remnant of what happened. In principle, it’s just that. You have a theoretical guess for how the early universe behaved. You work out its consequences. And among the consequences are certain regularities or certain features you can potentially observe in today’s world and see if they’re there or not.

And then, so you make a theory of the case, and a theory of what the crime was, and gather evidence, and it either strengthens your theory or makes you correct it or even discard it. But what there’s tremendously powerful evidence of, many, many lines of evidence, and few of which are mentioned in the book, is that about 13.7 billion years ago, the universe was much, much hotter, much, much denser, and much, much more uniformly populated with matter than it is today.

And since then, the matter has been expanding, cooling. And little inhomogeneities in it have undergone gravitational processing to congeal into the stars, and nebula-like planets, and so forth. So we have a broad-brush history of the universe and a lot of evidence of different kinds that gives a good description of what actually happened.

IRA FLATOW: Something that gets asked all the time is, what preceded the Big Bang? Well, tell us. What came before it?

FRANK WILCZEK: Well, I mean, we don’t know. We have very secure evidence, I would say, for the equations up to a certain point, which, roughly speaking, was when the universe was about a microsecond old or even a little bit less. What do I mean by a microsecond old if I can’t say what the beginning was? What I mean is that if you ran it back one more microsecond than the equations would break down. We don’t have evidence for what happened before that.

So we can make these models. But eventually, if we run things backwards, the matter is getting hotter and denser. And the interactions are getting further and further from our everyday experience. And we don’t have a lot of relics, a lot of clues from experiment about what was going on at those times. Most of them have been obliterated. And most potential evidence have been obliterated in the subsequent history.

So we don’t have a lot of observational handle on that era. And our equations become singular. They eventually break down. They become infinity equals infinity, basically, when you extrapolate down to the very, very earliest times. So we need new equations or we need new concepts in order to continue. And those are very much debated. There’s no consensus about it.

My own favorite idea is that the concept of time breaks down. Back then, the matter was very different and it may have been impossible to make anything that functioned as a clock. And so time, operationally, would cease to exist. That’s my favorite idea. But nobody knows, really. And so that’s an interesting frontier of physics, of course, tantalizing. But let me emphasize that we can understand a lot without understanding everything.

IRA FLATOW: What a way to start off the new year. You have given us so much to think about.

FRANK WILCZEK: This has been a joy, and thank you.

IRA FLATOW: I’d like to Thank my guest, Dr. Frank Wilczek, 2004 Nobel Laureate in physics. He’s the Herman Feshbach Professor of physics at MIT and author of the new book, Fundamentals, 10 Keys to Physics. And if you’d like to read an excerpt of his book, you can find one on our website at sciencefriday.com/fundamentals.

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