In his new book, "The Infinity Puzzle: Quantum Field Theory and the Hunt for an Orderly Universe," Oxford physicist Frank Close reviews decades' worth of brain-teasing theories and looks ahead to puzzles yet to be solved.
Close traces the decades-long effort to find the deep connections between the fundamental forces of nature and resolve the "infinity puzzle" — that is, the fact that the mathematics of quantum theory came up with nonsensical numbers. That puzzle was eventually solved, as Close describes in the book, but an even bigger puzzle remains: Why is the cosmos built the way it is?
Some clues could emerge from Europe's Large Hadron Collider, where physicists are looking for a mysterious particle known as the Higgs boson. Close delves into the strange role that the Higgs plays in contemporary physics, but he emphasizes that his latest book is about much more than the science.
"'The Infinity Puzzle' is not just another story about the physics of the LHC," he told me this week. "It's focusing on the people. Science is a pure ideal, but the scientists who do it are people. And we all have the same desires and pressures. ... There are heroes and villains in science, as there are everywhere."
Close's tale illustrates that the course of true science doesn't always run smooth. It may well turn out that the long-sought Higgs boson is a will-o'-the-wisp, and physicists will have to go back to square one. But even that won't render "The Infinity Puzzle" out of date.
"If the Higgs boson turns out not to exist, and we have to completely rewrite everything, this book will show how we got to this conundrum," Close said. "And if it does exist, hopefully it will explain why it was so important."
The book is particularly timely, considering that this year's Nobel Prize ceremonies are due to take place in Stockholm and Oslo next week. During a wide-ranging interview, Close discussed his book as well as the people and the puzzles that inspired it. Here's an edited version of the Q&A:
Cosmic Log: Could you explain what the "infinity puzzle" is?
Frank Close: The Large Hadron Collider at CERN is the biggest experiment that particle physics has ever set out to do. It's trying to find the answer to why there is structure in the universe. The buzzword you hear is the Higgs boson, and the question is, who is Higgs, what's the boson, what's it all about?
Well, what it's all about is what "The Infinity Puzzle" is trying to answer. In telling the story, the book focuses on the people who brought us to this remarkable point in history. And in particular it focuses on a group of scientists who discovered two separate things, half a century ago. First, how to unite the electromagnetic force, the force that holds you and me together and makes magnets work, with the weak force of radioactivity, which plays a very important part in how the sun burns. This is called the electroweak theory today.
The other part of the story is how to make a theory, which works beautifully if there is no mass in anything at all, work in a world where particles have mass. That has become known as the Higgs mechanism, and the consummate object we're looking for is the Higgs boson. The questions surrounding whether these things are named correctly, whether the people who won Nobel Prizes in the past were the right people, and whether there are going to be controversies over Nobel Prizes in the future for all of these things — those are the themes of the book. It's about the politics of science, the way that people are driven to want to get the big prizes. Scientists suffer the same emotions that everybody else does.
Q: You touch on many of those personalities — some who received Nobels, and some who didn't but deserved to. Do those personalities actually shape the science? Are there things in the universe that we see in a particular way just because a scientist first described it in that way?
A: It's a very interesting question about the role of personality in being able to tease out the secrets of nature. There are some people who are strong mathematical calculators but don't necessarily have great vision. There are other people who have got great vision, but aren't particularly strong calculators. It's when these two types get together that rapid progress is often made.
Ultimately, there's a truth out there, and we're trying to find what it is. It's different for artists. If you're a Beethoven, if you're proposing some symphony and you don't publish it, the chance that somebody else will create the very same symphony someday ... well, that just doesn't happen. But in the case of science, nature has already constructed the symphony, and we're trying to find what it is.
The challenge is, suppose that you have uncovered a bit of the symphony, but you're not sure whether you want to go public with it, so you don't publish it. Then, a short time later, somebody else does publish it, a bit braver than you, and you realize that you were right all along. You've lost the credit. There's a certain point where you have to be brave enough to jump off the diving board and take the plunge, to mix in another metaphor. There are many examples of people who didn't take that last step, for one reason or another. You know the names of the winners, but you don't know the ones who didn't quite make it.
Q: When it comes to the Higgs boson, the question has arisen as to whether it actually exists. One of my colleagues has joked that if it's found, that's worth a Nobel. And if it's ruled out, that's worth a Nobel as well. Is that the way it works?
A: The idea that has led to the Higgs boson is a piece of beautiful mathematics. Whether nature actually does it is a question that only experiments can answer. Although the theorists are the ones that get all the press ... the Einsteins and the other names that trip off the tongue ... it's ultimately the experiments that decide. That's where we are at the moment.
The idea that there should be a Higgs boson, or something else that masquerades as that particle, has been around for a long time. It's only now that are finally able to do the experiments that will tell us one way or the other if that is the case. And if it is the case, we might find out exactly how nature plays this particular trick. When Peter Higgs and a group of other people first put the idea forward, they were trying to solve a particular conundrum, and they came up with the simplest way of doing it — that is, that there was a single particle known as the Higgs boson. That was 50 years ago. Since then, people have refined those original ideas, based on the discoveries we have made.
There are several possible ideas as to how nature might actually do this conjuring trick. It might be there's a whole family of particles called Higgsinos and other weird names. It might not be a simple particle. It might be a compound — just as an atom has a nucleus that's made of protons and neutrons, which are made of smaller things called quarks, there might be new sorts of particles waiting to be found, called techniquarks, which collectively act as if they were a single boson.
It might be those, it might be something else. We simply don't know. And that's the exciting thing. Nature knows the answer at the moment, and we're trying to find out at last what it is.
Q: Is the Higgs boson the only door to new physics, or are there other routes to going beyond the Standard Model of physics?
A: We certainly know that the Standard Model cannot be the final answer. It describes everything that we currently have explored, but there are many things we have to put in by hand. The mass of the electron is put in by hand. Why it is what it is, we don't know. But if it were different, we wouldn't be having this conversation. You start by putting in all these measured numbers, and then we can describe a vast amount of stuff. But there must be some richer theory out there that will show why the Standard Model is as it is.
An analogy is Newton's laws of mechanics, which worked perfectly for hundreds of years. They were later incorporated inside Einstein's theory of relativity, which is a much richer, more powerful theory that includes Newton in it. We suspect there is a "theory of everything" out there which will contain the Standard Model. We are hoping we'll get close to the nature of that theory at the Large Hadron Collider. The LHC is exploring regions of nature we've never been able to explore before. We've seen them from afar — it's a bit like knowing there's somebody around the corner but you haven't seen them yet.
We are entering new territory. We're creating in the laboratory the conditions that the universe experienced about a trillionth of a second after the big bang. There are observations that have taken us to a billionth of a second after the big bang, so we've been pretty near. You might think, "Oh, why would we want to get nearer?" It's because the stuff that you and I are made of was created in that cauldron of the big bang's aftermath, and there are puzzles yet to be solved.
For example, why is anything left today? Antimatter is real, and matter and antimatter annihilate when they meet. So why didn't the newborn universe annihilate itself after the big bang. There must be something that tipped the balance. What that is, we don't know for sure, but some hints are beginning to emerge from the Large Hadron Collider.
The real thing is, we're exploring a new continent, and the LHC will show us what is there. That will then answer many of these questions —and if I knew the answers now, I'd be riding off to Stockholm.
Q: You mentioned the fact that some of the values in the Standard Model have to be put in by hand, and that scientists are trying to find out if there's a deeper theory that explains why those values are as they are. Some physicists have said that it might just be a lucky break that we have those values, and that our universe might be merely one of the "bubbles" sitting on the wider landscape of the multiverse. Do you subscribe to that landscape view of the multiverse?
A: Well, of course, the simple answer is, I don't know. And to be honest, nobody knows. I feel sometimes it's a bit of a cop-out. The universe I find myself in is difficult enough to describe. The idea that it is one of a huge number of universes ... that might indeed be true, but if we cannot experimentally answer whether it is true or not, I'm not sure whether the question is actually scientific. It's interesting philosophically. It's possible that someday we might be able to come up with an experiment that can answer whether there are other universes, but then you get into interesting tautological questions. The "universe" is presumably everything we can be aware of. If there are other universes that we cannot be aware of, then they're beyond the capability of science to investigate. But if they are investigatable through science, they are in a sense part of our universe.
The real question is this: Are the masses of electrons and other fundamental particles essential numbers in their own right, or are they no more fundamental than the radii of the planets around the sun? We don't know yet. I can't imagine anything that the Large Hadron Collider will discover that will give us a clear insight as to why particles have the masses that they do. But if we discover the Higgs boson, or whatever it is, we may well find out where mass comes from. And there may be some interesting quirk that comes out of that discovery that will give us a clue as to why the masses are as they are. The excitement of science is that until you've done it, you don't know.
Q: It seems to me that you were on a BBC program some years ago that touched on this whole discussion over whether a particle collider could destroy the world.
A: Yes, and the world hasn't ended yet.
Q: Some people would say the controversy was actually good for physics because it was a "teachable moment" that got people interested in physics. How do you see it?
A: Well, to be fair, it was a controversy that no scientist really subscribed to. It was something that somebody dreamt up, and it created an interesting sensation. But it does give the opportunity to explain what the Large Hadron Collider is and is not. The idea that we are doing things in the Large Hadron Collider that have never been done before is not the case. It's the first time that we have been able to do them. But the universe at large has collided particles together at energies far in excess of anything we do at the LHC or will ever be able to do. Cosmic rays in outer space are subatomic particles whipped into violent motion by magnetic fields in the cosmos — and they hit the upper atmosphere at energies far in excess of anything at the LHC.
Nature has done the experiments before, and we're still here. It's just the first time that we have been doing them under controlled conditions to tease things out. There are more things in life to worry about than that.
More about the puzzles of physics:
- Three win Nobel for discovering cosmic speedup
- Physics prize highlights puzzles
- Hidden universes revealed
- Special report on the Large Hadron Collider
Close will make an appearance at Town Hall Seattle at 7:30 p.m. PT Friday to talk about his book and the Large Hadron Collider, and is due to visit Kepler's Books in Menlo Park, Calif., at 7 p.m. PT Dec. 6.
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