Perimeter Institute's Big Thinkers
Not even the PERIMETER INSTITUTE FOR THEORETICAL PHYSICS in Waterloo, Ont., is immune to the rhythms of the seasons. Summer there this year was quiet and casual, with several regular faces away on vacation. And yet there were plenty of signs that the little think tank is heading into an ambitious new era.
Stephen Hawking was on a six-week working visit from Cambridge, England. Every day you could see a caregiver pushing his wheelchair along the footpaths outside the building at surprising speed. The most famous scientist in the world does not like to dawdle. Amyotrophic lateral sclerosis has left him no control over most of his body. Twitching a cheek muscle to compose even a short sentence with his speech synthesizer can take 20 minutes. So he is keenly aware of wasted time. "I encouraged lots of people to go and talk to him," Neil Turok, Perimeter's South African director and a Hawking friend and colleague of long standing, told me. "A lot of people did. Several of them came away saying, 'I went and explained to him what I'm doing - and he didn't seem very interested!' I entirely sympathize with him. He has very high standards and if you start telling him something that doesn't sound plausible he'll very quickly tell you, 'I've had enough.' "
Leonard Susskind, a white-bearded and soft-spoken Stanford University prof, was on a similar extended visit. Susskind has no human story of physical courage to match Hawking's, but to physicists he is in Hawking's intellectual class. He is a pioneer in the surreal but influential field of string theory, which describes a universe made of tiny vibrating strings curled up across many more dimensions than the three we know. Hawking and Susskind are two of Perimeter's 20 Distinguished Research Chairs, eminent international theorists who visit Waterloo occasionally to work without the distractions of home.
Susskind spent much of his time in the third-floor lounge surrounded by groups of young scientists still in graduate school or fresh out. They would show Susskind their work, neat lines of equations on notepaper or hectic scrawls on the lounge's blackboard. (Perimeter has hundreds of blackboards, in every office, conference room and coffee nook. They all get a lot of use.) Susskind's questions would make his young visitors stare at the paper or blackboard for long minutes, as if hoping an answer would appear.
The day I arrived, the inaugural class of Perimeter Scholars International (PSI), an intensive master's-level course in theoretical PHYSICS l for students from around the world, held their convocation after a year's intensive study. One of the most impressive was Bruno Le Floch, a 20-year-old ponytailed Frenchman who was one of the younger students in his class. "He's just a genius," Turok said. But he is also just a kid. So rather than dive into a theory career, Le Floch will spend the next year teaching in Cape Town at the African Institute for Mathematical Studies, which Turok founded in hopes of giving Africa's best students a reason to stay at home and lead the continent's intellectual development.
One day Stephen Harper visited Perimeter to announce a $20-million federal investment in Turok's African initiative. One rarely has to wait long at Perimeter before somebody comes along with a gift of money. Often the visitor is a local boy who made good, Mike LAZARIDIS, the founder and co-CEO of RESEARCH IN MOTION. Years ago, Lazaridis decided to put much of his fortune into an institute that would study the questions that fascinated him when he was a UNIVERSITY OF WATERLOO engineering student. On one hand, Einstein's theories of space, time and gravity. On the other, the odd but powerful insights of quantum mechanics. In 2000, with $100 million from Lazaridis and $20 million from two other RIM partners, the Perimeter Institute for Theoretical Physics set up shop in the old post office building on King Street.
Since then it has grown steadily. In 2004, Perimeter moved into a slate-black 6,000-sq.-m building on the shore of Silver Lake in Waterloo Park. Already this summer, work crews were building an extension that will nearly double the institute's floor space. Its faculty size will triple. (Current full-time faculty is only 11, but if you add faculty it shares with area universities, visiting scholars, post-docs and graduate students, there are about 100 people thinking in the building on an ordinary day, and often about as many stopping through for a conference or seminar.) Enrolment at Perimeter Scholars International will double. The Distinguished Research Chairs will grow in number to 30.
But what do the people at Perimeter actually do? Many assume the institute must be the research and development branch of Research in Motion. This is not even remotely true. There are no laboratories at Perimeter. It has no equipment for manufacturing anything. There is very little in the sleek four-storey building except boxes of chalk and an excellent bistro.
But establishing what the Perimeter theorists don't do is easier than explaining what they do. Even they have learned to leave it vague. "When the neighbours ask, I say I just want to understand why the universe works the way it does," said Chris Fuchs, a tremendously engaging Texan who has been a visiting scholar at Perimeter since 2007. "And that's when they usually say, 'Isn't it great that Stephen Hawking's there?' And I say, 'Yeah, it is.' "
What Perimeter's theorists do is think, singly and in groups. Sometimes they scribble equations on the chalkboards to enlist colleagues and visitors in their attempts to solve some new or nagging riddle. Once I passed Fuchs's office on my way to the third-floor pop machine. He was staring intently, slack-jawed, at the chalkboard that makes up one wall of his office. When I returned 20 minutes later he had not moved.
What they think about, from assorted conceptual angles that make up the subdisciplines of modern theoretical physics, are ways to refine, extend and, ideally, reconcile the two great early 20th-century advances in physics - general relativity and quantum mechanics. Relativity refers to Albert Einstein's realization that space and time are aspects of the same thing, as are matter and energy. Einstein described how massive bodies like stars warp the space-time around them, bending the fabric of existence in a way we experience as gravity.
Quantum mechanics is the product of research into the behaviour of the component parts of atoms by Einstein's contemporaries - Bohr, Heisenberg, Schrödinger and others. What they found is so odd it still puzzles physicists. A particle can sometimes be in one place and, in a way, somewhere else at the same time. Observing a particle to find out where it is destroys any chance of knowing for sure where it's going. Two particles can become "entangled" so that a change to one particle will be reflected in a change to the other, no matter how distant.
In nearly a century of investigation, researchers have made great use of these odd insights. Electronics depends on the quantum behaviour of electrons moving through semiconductors. The same phenomena drive lasers, DVD players, computers, electron microscopes. The Nobel-winning physicist Leon Lederman has said that quantum mechanics is responsible for one-third of U.S. GDP.
The big conundrum in physics is that the great breakthroughs of relativity and quantum theory do not play well together. Quantum mechanics is good at describing just about everything matter does - except gravity. And Einstein's relativity theory breaks down at the very short distances where quantum phenomena operate.
This apparent incompatibility between great discoveries is catnip to physicists. They know that every time connections have been found between phenomena that once seemed unrelated, somebody soon figured out how to put the discovery to practical use. In 1864, James Clerk Maxwell showed that electricity and magnetism are the same thing. His discovery of electromagnetism led to the invention of radio. Einstein's unification of matter and energy in 1905 made the atom bomb possible. "It's never been true that you could look at the universe in new ways and not see something unexpected," Cliff Burgess, a particle theorist who divides his time between Perimeter and MCMASTER UNIVERSITY, told me.
Perimeter's faculty and visitors poke at the boundaries of their disciplines in any number of different ways. What makes Perimeter unique is the extent to which different subdisciplines are given substantial resources and thrown together in ways designed to encourage co-operation and confrontation. But if a common theme links much of their work this year, it is the belief that a reality check is coming. A generation of theorizing will soon be tested against hard data from significant new experiments.
Nothing motivates a theorist more than new information from the real world, especially if it upends what everyone thought they knew.
Almost everyone in physics believes a moment like that will arrive within the next few years. The largest scientific experiment anyone has ever built is the Large Hadron Collider (LHC), a particle accelerator 27 km in circumference that lies under the border between France and Switzerland. Two of Perimeter's youngest, newest hires have won a disproportionate influence over how data from the LHC will be collected and disseminated.
Last year, Philip Schuster and Natalia Toro applied to be post-doctoral fellows at Perimeter. She's Colombian, he's American. They're a couple. They finished their Ph.D.s at Harvard in 2007. They'd been working in junior positions at the Stanford Linear Accelerator near San Francisco. "If you look at them on paper they're not really that unusual," Turok told me. "Citations are not high. They haven't published very many papers." So they're untested, not prolific and not influential. Yet they sent glowing letters of recommendation from scientists Turok trusts, including B.J. Bjorken, a leading particle physicist. "He just said, 'These people are exceptional.' "
The reason Schuster and Toro haven't been publishing papers is that they have been working with the huge experimental teams at LHC and other particle accelerators in other countries. "That's extremely unusual," Turok said. "I mean, I did my Ph.D. in a particle physics group, with an experimental physics group next door, at Imperial College. And the two never talked. We never went to their seminars. They never came to ours."
Theorists get to abstract the world down to dots and vectors on a chalkboard. They work alone or with a few colleagues. Modern experiments are infernal contraptions run by committee. "Everything becomes driven by the nuts and bolts of the experiment. 'Who's going to buy the aluminium tubes?' And the theorist takes one look at this and moves in the other direction."
But the LHC is worth extra effort. It is not just another ring under the ground. Particle accelerators smash streams of elementary particles together at tremendous speeds, then pick through the rubble for hints about forces too subtle to measure any other way. LHC is so big so it can collide protons at much higher energy than earlier experiments. The higher the energy, the smaller the size of the phenomena that can be observed. This matters because some particles decay in an instant into other particles. If you want to see them you have to catch them in the tiny moment before they transform into something more mundane.
The LHC started operating in 2008 but soon ran into significant technical problems. It will operate at only half its designed power until 2012. The distance it will probe once the bugs are ironed out is 10-17 cm, about 1,000 times smaller than the protons that are colliding. It has taken collider designers decades to get this small, and there are all kinds of hints that this scale is significant in ways larger scales weren't. "Some of the pressing mysteries that we're trying to explain are, what is the origin of mass? Why is gravity so weak compared to the other interactions? And also, are there extra dimensions or do we just have four space-time dimensions?" Schuster told me via Skype from a particle accelerator in Virginia. These are huge questions. Confirmation of other dimensions would turn science on its ear - as would the inability to find extra dimensions at this tiny length scale. Knowing why gravity behaves differently from other forces might, one day, make it possible to channel gravity the way we use electricity in every wall socket.
There are strong theoretical reasons to believe the answers to some of those questions lie way down at the length scale the LHC was built to probe. And most theorists suspect there will be surprises, evidence of phenomena nobody even thought to look for. In recent decades smaller colliders were mostly built to confirm strong predictions. Now, "the situation is not like what it was back in the early '80s," Schuster said. Back then, experimentalists were simply confirming very precise predictions made by a well-understood set of theories and observations called the Standard Model. And indeed, when colliders started operating at the length scale needed to test these predictions, they found the particles they were expecting.
"The situation now could not be more different," Schuster said. "Essentially we have no solid, clear hints for what's going on at the length scale the LHC will probe. We have a lot of ideas out there. And certainly we've had time to develop them and there's quite a few floating around. But if you were to survey theorists, 'What will we find at the LHC?,' you would fill out a whole spectrum of answers.
"Nobody knows, okay? We're very much in a situation where experiment is going to have to lead the way."
Now here's the thing about data from the LHC. Each experiment involves trillions of particles. Measuring the results produces vast amounts of data, 15 million gigabytes a year, enough to fill 94,000 of the largest iPods. It's a complex and delicate business. Sometimes parts of the collector work properly and others don't. Sometimes an angle is wider than expected or a particle seems to have more momentum than predicted. That is exactly what the evidence for strange new forces would look like. But on any given occasion it could just be math that hasn't been triple-checked properly. And if a theorist catches wind of one of these false leads, pretty soon it'll be on the front page of the Daily Telegraph or the New York Times, false reports of a revolution forcing hasty news conferences to set the record straight, confusing everyone, undermining the credibility of the whole enterprise.
So experimental groups never publish their raw data. "Theorists do not have access to the data," Schuster said. "They are forbidden from seeing the data. And the experimentalists actually do not show most of what they see." They're like a college of cardinals who send up a puff of white smoke only when they are sure they have found something new, or can cross a theory off the list by showing that something the theory predicted has failed to turn up. All of this makes the experimental groups' method for reporting their results important: it's the only window a world of theorists have into the results.
This is where Toro and Schuster come in. "The way that we are used to doing things is, you have a theory, you try to work it out in detail, you make predictions for what a hadron collider will see, and then it's sort of a binary 'yes' or 'no': you either see a certain feature in the data or you don't," Schuster said.
That was good enough at lower energy levels when physicists were looking for confirmation of strong predictions. But nobody knows what the LHC will find, and candidate theories are lined up around the block. It will take forever to check every theory one by one. And what's crucial is that there may be something going on that no theory predicts.
"What we need is basic information," Schuster said. "Not hyper-refined, detailed information." So Schuster and Toro, along with their Harvard thesis adviser Nima Arkani-Hamed and other colleagues, spent three years working on a method for describing the results of a particle collision much more generically. There are particles of such-and-such mass, their decay rate was this fast, they scattered in this pattern, and so on.
On the basis of those early reports, theorists with competing ideas will all be able to look at the clues from the LHC, discard some theories that don't fit and come up with new questions for the next round of experiments. It should be far more efficient than an endless list of yes-no questions.
To change the approach, Toro and Schuster had to win the trust of experimentalists who outnumbered them. The two young theorists spent two months in Europe with one of the LHC experimental groups, a group of 40 researchers from the University of California, Santa Barbara. "We showed them these ideas. They were certainly still very skeptical. But over the course of those two months we learned quite a bit more about how analysis is done inside the collaborations," Schuster said. "We refined some of the ideas we had had before. And we also started working through exercises, test cases."
They kept returning to Europe for two years to work on their ideas, which became increasingly popular "largely because it made their task of characterizing the data easier." In the middle of their courtship with the people who run the largest experiment in history, Toro and Schuster applied for post-doc positions at Perimeter. After a little due diligence Turok decided to oblige. "We offered them post-docs. We knew to get them we'd have to at least offer them five-year post-docs. Princeton then offered them three-year post-docs at the Institute for Advanced Study, which is considered one of the best places in the world. They really wanted to go to Princeton. So at that point we changed our offer to junior faculty." It worked. Toro and Schuster joined Perimeter.
It was a bold move to grab two kids who'd been buried in caverns for two years. "But they are exactly the kind of people we want to recruit. They are driven primarily by the desire to make a genuine discovery, not by the need to publish papers. That's exactly what we're after. That's the whole culture I'm trying to install here."
Why? Look at the result. "We're paying, you know, two junior-faculty salaries and we're right at the heart of this multi-billion-dollar experiment."
Turok's ambition is to extend Perimeter's influence with a series of similar moves. Boyish and jug-eared, he was already a leading theorist of the universe's origins when Lazaridis and the Perimeter board hired him in 2008. He brought with him something else - the clout of a respected practitioner. Hawking's visits result from his personal friendship with Turok.
The institution's new five-year plan carries the title "Expanding the Perimeter." When a circle's perimeter expands it grows in every direction. And so with this place. "When he announced PSI," said Rob Myers, a string theorist who acted as interim director before Turok arrived, "they announced it in October and by May the first class was here. Everything's moving so quickly."
The PSI, the master's-level educational program, is not a vanity project. "He's trying to strategically pick off the brightest kids, before they go to Harvard, Cal Tech, MIT," a Perimeter staffer said. Competition for talent preoccupies Turok. The world does have other theoretical physics institutes. Most are older and university-affiliated. Perimeter has to be clever about competing. "When we try to recruit people, we're always looking slightly under the radar of other institutions," Turok said. "And we invite [candidates for recruitment] to come here and give a series of lectures. It's our standard way of recruiting."
This poses a problem. Perimeter records video of every lecture and posts it online within days. "Stanford, Harvard, Princeton are watching our lectures to see how a given recruit did. I know this for a fact," Turok states.
He dismisses this leak in his human-resources pipeline with a rueful chuckle. He fights back by making Perimeter more competitive. He hopes soon to begin announcing five Perimeter Research Chairs, full-time endowed positions designed to lure five world-leading theorists from their perches abroad. Each chair will be endowed at the $10-million level so the chairholders can hire younger colleagues to form study groups. Turok is already talking to potential chairs, and to corporate sponsors who would fund each position.
But science has usually been a young person's game. Stephen Hawking was in his late 20s when he began making breakthrough discoveries about black holes. So even as he courts the field's most established names, Turok continues to take flyers on young recruits who use audacious math to model complex processes.
Pedro Vieira from Portugal is one. "We hired this guy six months out of his Ph.D. Most of our scientific advisory committee felt this was very unwise. He's just so young." Another, Freddy Cachazo from Venezuela, has found that complex numbers produce elegant solutions for predicting the way particles will scatter in a collider. That's just weird. A complex number has an imaginary component, such as the square root of a negative number. It's not at all clear why non-real numbers produce such nice predictions for real-world events.
"It's real hard-core stuff," Turok said of his new recruits' work. "Nobody will accuse Perimeter of being flaky, soft, pretty much philosophy, etc. This is pretty much the opposite. And in my view, that's a good thing. I don't want this to be a philosophy centre. It's got to be a real hard-core place."
But perhaps because I'm never going to understand the math, what struck me again and again about these people was how much heart they bring to the task at hand. One afternoon I attended the weekly meeting of Perimeter's loop quantum gravity group. Lee Smolin chaired the meeting. Smolin was one of Perimeter's first faculty members and at only 55 he is one of the oldest. He is also easily the most controversial. His 2006 book The Trouble With Physics is a lament about the predominance of string theory. The discipline's mathematical complexities attract a lot of what Smolin calls, with a measure of disdain, "master craftspeople." The problem, he argued, is that string theory gets lost in the tall grass of problem solving for its own sake. It becomes too easy to lose track of the big questions, the origin of the universe, the nature of space and time. That's "exactly what you get," Smolin wrote, "when a lot of highly trained master craftspeople try to do the work of seers."
Those were fighting words. Everyone at Perimeter is heartily sick of the controversy Smolin kicked up. The surprise was that Smolin is such a soft-spoken fellow, interested in art and architecture, a bit of a mother hen to the institute's younger scholars.
"What's powerful about Perimeter is that it draws strength from oppositions," Smolin said. "So we have a good string theory group - and a good group in non-string theory approaches to quantum gravity. That's very important. And we've developed an atmosphere to nurture that opposition: we're very friendly, we're very supportive. We've never had a political fight here over, you know, 'Hire that person, hire this person.' And we're hard on each other. In a proper scientific way, not an unfriendly or competitive way."
Some of that spirit was on display at the meeting of Smolin's group. Loop quantum gravity is an alternative to string theory among attempts to reconcile gravity and quantum mechanics. It involves something called spin foam. For the sake of decorum I'll stop there. I flunked out of second-year chemistry 24 years ago. Most of what the dozen men around the table said would not have been less comprehensible to me if I were listening in on the clicks and whistles of sentient dolphins. But the mood was one of gentle, playful challenge.
Smolin went around the table, asking everyone to report in turn on their current work or, if they prefer, on something they've read or heard that intrigues them. He interrupted the first speaker almost immediately: "Plain English, please. No jargon." That led everyone to use a little less jargon. Smolin continued around the table. "That's not a new idea," he chided one colleague. A visiting third-year undergrad from Penn State University, the youngest person in the room, reported on his work. Smolin did the same when his turn came. There was no visible hierarchy by experience. The conference room's six chalkboards filled up quickly.
Soon it was Rob Spekkens's turn to speak. Spekkens belongs to Perimeter's quantum foundations group. He does not normally attend Smolin's group meeting. Today, he had a thought experiment that was nagging him. He drew two stick figures, Alice and Bob, and said he needed a mechanism for passing one bit of information between them, a simple zero or one, but no more. Did anyone have any ideas? The loop quantum gravity group pondered the riddle in silence.
If anyone can usually be counted on to ask a simple question that stumps a room, it is the quantum-foundations people. By now, 80 years after the first discoveries in quantum mechanics, the weird behaviour of tiny particles is well documented and reliably described by mathematics. But that's not the same as understanding how it works. How can a thing be in two places at once? How can the state of a system depend on whether anyone's looking at it?
To many physicists these are fussy questions with little interest. What matters is that the math works. "In many places foundations was considered a lost cause because there were no experiments that suggested quantum mechanics was wrong," Smolin said. "But there's a persistent sense among many people that quantum mechanics is incomplete or confusing. Or there's something left out of the story. That's mostly been pushed to the sides of academic science. It's a very important part of Perimeter that it's here in a big way."
Spekkens, an easygoing man with red hair and beard, studied physics and philosophy at MCGILL before master's and doctoral studies in physics at the UNIVERSITY OF TORONTO. It is not easy for young physicists to turn their interest into a career. Many wind up at software companies or in brokerage firms, calculating the motion of the financial markets. Spekkens decided he was young enough to worry about his career later. "I said to myself, for the next five years I'm going to do what I want to do. And if that's the end of my career in physics, so be it." Luckily for him, Perimeter Institute was getting going. A post-doc appointment in 2002 led to a faculty appointment for Spekkens in 2008.
One muggy evening I went along with Spekkens and Latham Boyle, a cosmologist from Ohio who joined the Perimeter faculty this year, to visit Chris Fuchs. We went to Fuchs's house because last Fathers' Day his wife and daughters bought a $35 chalkboard from Kijiji and mounted it on the front porch. It seemed like a good place for a chat.
"Chris Fuchs sees himself as the embodiment of the American tradition of pragmatism reborn as a physicist," Smolin told me. "He's intellectually in a very interesting place. Not a lot of academic centres would include him." Philosophy books far outnumber physics texts in the old hardwood bookcase in Fuchs's study. There are books by and about Heidegger, C.S. Lewis, Santayana, Wittgenstein. Mostly the little library is a shrine to William James, the 19th-century pragmatist who held that the value of anything depends on its usefulness to the observer. "The knower is not simply a mirror floating with no foothold anywhere, and passively reflecting an order that he comes upon and finds simply existing," James wrote in 1878. "The knower is an actor, and coefficient of the truth...In other words, there belongs to mind, from its birth upward, a spontaneity, a vote. It is in the game."
Those words amazed Fuchs when he first read them. They read like a forecast of quantum theory. "This is a participatory universe," Fuchs told our little crowd as we headed out to the porch and the chalkboard. "The big bang is here all around us. It's not a written-out story."
That made Latham Boyle chuckle. "I didn't realize what a mystical figure you are," he told Fuchs. "You should be on a mountaintop."
But just about everyone at Perimeter has a mystical side. Fuchs had sent me links to some theoretical physics blogs. I mentioned that one blogger suggests the human mind may simply not be sophisticated enough to understand the nature of the universe. Boyle cut in. "Bah!"
I persisted. Rabbits don't understand the universe, after all. Earthworms don't. Sure, humans evolved language, but despite its glories language began as just another tool to help us find mates and food. It may be hubris on our part to believe we're cut out for decoding the universe just because we can order out for pizza.
Boyle didn't like that any better. "Aaaah!"
Why couldn't he believe the universe might simply be beyond our grasp? "It's an article of faith," he said bashfully.
"Almost everyone at PI is doing physics in what I would call a more romantic style than other places," Spekkens said. That certainly includes Boyle.
While others concentrate on tiny particles, he studies black holes for the clues they can offer into the origin of the universe. The distinction between the tiny and the vast isn't as stark as it appears. The same forces that operate at the smallest scale have affected the growth of the cosmos, so that studying either extreme gives insights into the other.
Boyle is designing an instrument for measuring gravity waves from orbiting pairs of black holes that he's dubbed the "perfect porcupine," because it would have spines that stick out and it would be highly symmetrical. He is haunted by symmetry, by the way the universe almost always turns out to be more beautiful and simple than people expected.
Einstein's equation for space-time is a non-linear partial differential equation. Those are really hard. Einstein didn't expect anyone ever to find a solution. But successive generations of theorists have found solutions to the equations under many circumstances. One such solution, from 1963, "has many, many special properties that you had no right to expect," Boyle told me in his office before we decamped to Fuchs's house. "It's like a diamond..." But he stopped himself, worried he was sounding silly.
Now on the porch he finished the thought. A diamond is beautiful, of course, in large part because it is symmetrical. And if you shine light through a diamond, the crystal splits the white light into a rainbow spectrum: it helps you understand something about light. Physics keeps working the same way. It helps to explain the world in ways that just happen to be elegant and symmetrical.
And any pursuit of physics that loses sight of these romantic considerations is, in some way, barren. "There must be some reason why the greatest breakthroughs came in times and places that weren't single-mindedly obsessed with the pursuit of physics," Boyle said. Why does the Large Hadron Collider matter? Is it because it might find the Higgs boson, a particle that adds mass to matter? "That's the most boring answer you could possibly give!" Boyle said.
The real answer, of course, is that there are new mysteries behind the threshold of 10-17 cm and a shot at tackling the riddles that will follow. What drives these people, it seemed to me, is something simple and admirable. They have managed to get further than most of us do in investigating the questions that begin, "I wonder why..." The payoff may be a technological revolution, someday, that would rival radio and transistors for its ability to change everything. But the real value is in what doesn't change: the ageless desire of great minds to get in the game.
Maclean's September 27, 2010