Big Think Interview With Peter Woit | Big Think

Big Think Interview With Peter Woit

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A conversation with the mathematical physicist at Columbia University.

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Peter Woit:

Peter Woit is a mathematical physicist at Columbia University. He graduated in 1979 from Harvard University with bachelor's and master's degrees in physics and obtained his PhD in particle theory from Princeton University in 1985. A prominent critic of string theory, he published a book on the subject, Not Even Wrong, in 2006, and maintains a blog of the same title.

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TRANSCRIPT:

Question: What is string theory?

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Peter Woit: Well the first thing I can say is, when people sit and talk about String Theory, they're actually talking about a very complex set of ideas that lots of people, a very large amount of people have worked on and have done a lot of different things with. Probably what it's best known for and what got people all excited about it in the physicist community is the conjecture that, at the most fundamental level, you can understand matter and the universe in terms not of point particles, which is the way our best theory is, currently, you can understand things, but in terms of, if you like, vibrating in loops of some elementary objects here, your elementary object instead of being a point-like thing is something you should think of more as a one dimensional loop, or a string which is kind of moving around.

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So, it has a lot more - it can do a lot more complicated things than a point, this kind of loop of elementary matter, whatever it is. And so, it gives you a very different class of theories than the ones that have been so successful before. So, during the '60's, this idea was initially developed and initially people tried to do one thing with these passive theories something which didn't work out that well. And then starting in the late '70's and '80's, people then came up with a conjecture that maybe you really could unify all of physics and solve some of the open problems in physics by replacing our standard theories, what we call the standard model with some kind of string theory. So, since this idea because very popular in 1984, and so it's been now 25 years people have been working very hard on that. And I just think the initial thing that got people excited was I would claim it really hasn't worked out and it really can't work out. And that's kind of been, I think, a lot of the reason the controversy has been an argument over this issue of whether this very speculative idea about whether you could use these strings, and you don't have to get a unified theory, about whether that has - is that an idea that's failed or is there still some hope for it, is what I think is really what's the controversial part of it.

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Question: What is the “grand unifying theory” that physicists are trying to formulate?

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Peter Woit: Well, the main thing to understand about the current state of physics is that we have - are in some sense, a kind of victim of our own success. We have an incredibly successful theory called the Standard Model. And it really explains everything that we can observe about and in terms of a very small number of elementary particles and some basic forces between them. And it's a quite beautiful theory and it really is just absurdly successful. Every experiment anybody knows how to do that in principle can be - that this theory has something to say about, it works out perfectly to whatever experimental and in whatever detail you can do an experiment to whatever precision, it come out to exactly as predicted by the model.

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So, we have a semi-unified theory. This quite nice, beautiful structure which explains everything we can see, but it still leaves open several questions. Some of the questions are just kind of why we have all these different particles and they all have different masses. Why do they all have different masses? We don't understand why the electron has a certain mass, quarks have other masses. So, there's just kind of things which the theory doesn't address. It just doesn't answer these questions and then questions which as physicists we think there should be answers to.

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But then there is also one remaining force which isn't part of the standard model, which is the gravitational force. The gravitational force is much, much weaker than these other forces and it has a somewhat different nature, so the problem with it is we don't - these other forces we have something which is a quantum theory.

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