A Force of Nature
The atomic world is a strange place. But researchers like Raymond Laflamme at the University of Waterloo want to harness the forces of the quantum realm to build a new kind of computer.
Dr. Raymond Laflamme thinks the development of quantum computing is going to have some big consequences.
When describing how big, the director of the Institute for Quantum Computing at Waterloo University mentions milestones like the mastery of fire and the invention of the wheel. “Every time we’ve been able to control a force of nature,” he says, “technologies follow and society changes.”
The force of nature Dr. Laflamme is talking about is the behaviour of objects at the atomic and subatomic scale. In this topsy-turvy realm of “quantum mechanics,” the laws of the physical world described by Isaac Newton are broken every instant. To give just one example: at the atomic scale, it’s normal for one particle to be in two places or states at the same time—a phenomenon known as “superposition.” How can this be? Don’t ask. Even the scientists who first described this bizarre world found it unsettling. “Anyone who thinks they can talk about quantum theory without feeling dizzy,” Niels Bohr once said, “hasn’t yet understood the first word about it.”
The principles of quantum mechanics, however, can and have been experimentally verified in the lab. And applied to the world of computing, they’re poised to change everything. Using facilities funded in part by the Ontario Innovation Trust, researchers like Raymond Laflamme are looking at ways of harnessing phenomenon like superposition to design computers of almost unimaginable power. “We’re not talking about something like stepping up to a more powerful chip,” he explains. “It’s going to be a fundamental break in the way information is manipulated.” (See “Bits and Qubits”)
The earliest application—and the one currently driving most research—is likely to be in cryptography. Current code systems are designed to be essentially unbreakable—meaning that it would take either billions of today’s computers or billions of years to crack the most sophisticated schemes. But we’re only fifteen or twenty years away from quantum computers that will be able to do the job in days or hours. The good news is that quantum cryptography will also introduce new ways to make data secure. In fact, basic quantum encryption techniques are already in commercial use.
Not surprisingly, tomorrow’s quantum computers will also be very good at modeling the strange quantum dynamics of the atomic and subatomic world—a task that quickly overwhelms classical computation. And that promises to revolutionize endeavours like drug design and the development of completely new materials.
Even the weaknesses of the technology point to tantalizing possibilities. Quantum systems are very fragile, but Dr. Laflamme believes that we’ll be able to exploit this extreme sensitivity to develop new types of sensors. Combine these sensors with the power of quantum computing to handle the massive amounts of data they would generate, and the result could be a new age of human discovery. “I believe that this technology will allow us to enter a new world and open new ways of manipulating information such as in quantum teleportation.”
How long will we have to wait for these kinds of breakthroughs? The timeline keeps getting shorter. “When I started working in the area 10 years ago,” Dr. Laflamme remembers, “people thought we wouldn’t see quantum computers for 50 to 100 years.” Now he believes that practical, working machines are more like 15 to 20 years away. He warns, however, that such devices aren’t even at the engineering stage, and compares current plans to early airplane designs that included flapping wings.
Dr. Laflamme is even cautious about the predicted applications. But it’s an optimistic kind of caution. “In 30 or 40 years,” he says, “the examples I’ve mentioned may not even be the most important applications. But whatever they are, I really believe this will change our society.”
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“The opportunity is there, and I want to grab it.” A major figure in the world of physics has returned to Canada to help build the computer of tomorrow. Raymond Laflamme’s star has been rising ever since he finished his undergraduate degree at Université Laval and headed for Cambridge in 1983. At the famous British university, he ended up working closely with the world-famous Stephen Hawking, even influencing some of Hawking’s thinking in A Brief History of Time. After appointments at the University of British Columbia, and again at Cambridge, Laflamme went to Los Alamos National Laboratory in New Mexico in 1992 to spearhead research into the exotic field of quantum computing. But now the establishment of a new Institute for Quantum Computing—funded in part by an investment from the Ontario Innovation Trust—has attracted him to the University of Waterloo. “I came with the feeling that I can really build something new from scratch...do something really extraordinary. The opportunity is there, and I want to grab it.” Quotations from the Waterloo Record, January 3, 2004 |
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Exponential Power:
Bits and Qubits
In the computers on our desktops, the basic unit of information is the “bit,” which can have a single binary value: 1 or 0, on or off. This value is stored as an electrical charge—or lack of one—on a silicon chip.
A quantum computer, by contrast, uses technologies like nuclear magnetic resonance to store values in units known as “qubits,” by altering the states of particles at the atomic level. Because of the principle of superposition, these particles can be in two states at the same time, meaning that a qubit can hold two binary values simultaneously—it can be both 1 and 0, on and off.
Here’s where the math gets interesting. In a simple two-bit classical computer, for example, information can be stored in one of four different two-character combinations: 00, 01, 10 and 11—but only one combination at a time. In a two-qubit quantum computer, however, superposition means that both characters can be a 1 and a 0 at the same time, with the result that all four combinations can be stored simultaneously. Add another bit to our classical computer and you get eight possible three-character combinations—but the computer can still only store one at a time. Add a qubit to our quantum computer and you can work with all eight. Each additional qubit doubles capacity – and as with any geometric progression, the numbers get very big, very quickly.
Of course, today’s best desktop computers deal with data in large 64-bit chunks, while experimental quantum computers max out at around 10 qubits. But at about 30 qubits, a quantum computer would be three times as powerful as today’s fastest super computer. And with each added qubit, that power grows exponentially.
Bits and Qubits
In the computers on our desktops, the basic unit of information is the “bit,” which can have a single binary value: 1 or 0, on or off. This value is stored as an electrical charge—or lack of one—on a silicon chip.
A quantum computer, by contrast, uses technologies like nuclear magnetic resonance to store values in units known as “qubits,” by altering the states of particles at the atomic level. Because of the principle of superposition, these particles can be in two states at the same time, meaning that a qubit can hold two binary values simultaneously—it can be both 1 and 0, on and off.
Here’s where the math gets interesting. In a simple two-bit classical computer, for example, information can be stored in one of four different two-character combinations: 00, 01, 10 and 11—but only one combination at a time. In a two-qubit quantum computer, however, superposition means that both characters can be a 1 and a 0 at the same time, with the result that all four combinations can be stored simultaneously. Add another bit to our classical computer and you get eight possible three-character combinations—but the computer can still only store one at a time. Add a qubit to our quantum computer and you can work with all eight. Each additional qubit doubles capacity – and as with any geometric progression, the numbers get very big, very quickly.
Of course, today’s best desktop computers deal with data in large 64-bit chunks, while experimental quantum computers max out at around 10 qubits. But at about 30 qubits, a quantum computer would be three times as powerful as today’s fastest super computer. And with each added qubit, that power grows exponentially.