Waterloo is now the biggest place in the world for quantum computing, says MIT’s Scott Aaronson. “Canada is punching way, way above its weight”
the basic science behind this new field. (A few years earlier, Lazaridis had founded the Perimeter Institute for Theoretical Physics, also located in Waterloo.) With funding from the Canadian and Ontario governments, the University of Waterloo, an array of corporate partners and a good chunk of Lazaridis’ personal fortune, IQC was soon up and running. Laflamme, who had been working at Los Alamos National Laboratory in New Mexico, was recruited as director. In 2012, the facility expanded into a new, 285,000-sq.-ft., $160-million building known as the Mike & Ophelia Lazaridis Quantum-Nano Centre. Researchers at IQC are leading Canada’s foray into the
quantum world, but they’re not the only ones peering eagerly into the subatomic realm. Some of the world’s largest corpora- tions, from Google to Lockheed Martin, are getting in on the action. So is the US government (according to information leaked by Edward Snowden last year, the US National Security Agency has put US$80 million into a quantum computation project called Penetrating Hard Targets), as well as the UK, the European Union, Switzerland, Australia and Japan. To see why so many are banking so much on the idea of a
quantum computer, we need to embark on a brief tour through quantumland. In the everyday world of trees and cars and base- balls and houses — what physicists call the “classical” world — you can usually tell where something is and where it’s going. But zoom in by a factor of a few billion and the picture changes. At the quantum scale, a particle can be in two places at once — or, more generally, it can be in two “states” at once — a phenome- non known as “superposition.” And that goes for the fundamen- tal “bits” used in computers, too. In classical computing, a bit can be either a zero or a one. But a quantum bit, known as a qubit, can be both a zero and a one at the same time. Thanks to superposition, qubits can be used to perform huge numbers of calculations simultaneously. Moreover, because the power of a quantum computer scales exponentially in propor- tion to the number of qubits in its memory (two qubits can perform four calculations at once, three can do eight, four can do 16, and so on), it offers an exponential increase in computing power over today’s machines. “If we had a small quantum com- puter, with 40 to 50 qubits, we could do calculations that, if we had all the classical computers on earth, we would never be able to do,” says Laflamme. “It’s a mind-bogglingly powerful parallelism.” One of the most-oſten touted applications is in cryptography.
Much of the data that whizzes through the Internet today — everything from credit card purchases to medical, business and government records — is secured using a method called RSA coding. At the heart of the system is a simple truth about multi- plication and division. Suppose you take two prime numbers that are hundreds of digits each and multiply them together.
44 | CPA MAGAZINE | JUNE/JULY 2015
That’s easy; any computer can work out the product. But given only the product, working backward to deduce the two prime factors is a nightmare; no ordinary computer is up to the task. A quantum computer, on the other hand, could handle it — effec- tively rendering today’s best codes obsolete. At the same time, quantum theory has some researchers thinking about new kinds of codes — perhaps unbreakable ones. Other potential applications range from drug development and medical imaging to database management and artificial intelligence. The path from blackboard to laboratory, however, is proving
to be a long one. For starters, it’s not immediately clear what a qubit should consist of. In classical computing, the usual choice is electrons — or rather, pulses of many thousands of electrons; each electron carries an electrical charge and manipulating bundles of electrons is fairly straightforward. Engineers learned how to design “logic gates” — tiny electrical switches — for manipulating those bundles of electrons, allowing for the con- struction of circuits that can implement algorithms. The first logic gates used vacuum tubes; later these gave way to transis- tors. But qubits need to be in a state of superposition, which makes everything a lot harder. Photons (particles of light) are one possibility; ions (atoms that carry an electrical charge) are another; superconductors (supercooled materials, usually metals that carry electrical currents without any loss) are yet another. “It may take us a while to figure out which is the best architecture,” says Aephraim Steinberg, a physicist at the University of Toronto. Another problem is that quantum states are inherently
fragile; if you poke at them even slightly they “decohere” — that is, they stop displaying quantum properties and start acting like ordinary classical matter. But you need to poke at them to input and output information — in other words, for computation. Yet another problem is error correction. Each time a bit is pro- cessed there’s a risk of making a mistake. Classical computers get around the problem with redundancy; instead of doing something once they do it multiple times to make sure they keep getting the same result. Quantum computers can get by with fewer bits — because each quantum bit is so powerful — but at the same time, each qubit is far more prone to error. But progress is being made, says Laflamme. “We’ve gone from a few qubits with about 10% error 10 years ago to 0.01% error and a dozen qubits today,” he says. “It’s progress we can quantify.” While IQC’s current focus is on pure science — discovery for
its own sake — Laflamme insists there will be a payoff. “What we want to do in the next 10 years is to take advantage of this science, to turn it into technology, to commercialize it,” he says. Quantum computation could revolutionize any field where huge amounts of data need to be processed. Lockheed Martin, for example, is using the technology to test the soſtware used to
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78