ATHENS, Ga. – It should work. Scientists believe it will work. And yet, as University of Georgia researchers leap into what could be the next breakthrough in computers and computer power, uncertainties remain. But don’t share doubts with UGA physicist Michael Geller. His research has been building toward the construction of a quantum computer for much of his career.
Buoyed by a new $2 million grant from the National Science Foundation, Geller and a team of co-principal investigators at UGA and elsewhere have begun work on this new kind of computer that could more efficiently and more rapidly solve problems in such fields as cryptography, mathematics and physics.
In truth, since no quantum computer has yet been built, researchers aren’t quite sure what kinds of problems they may encounter. But there’s no doubt in Geller’s mind or those of scientists worldwide that a quantum computer at some scale will be available to scientists in only a few years.
“Quantum computing promises to solve very specific but important problems,” said Geller, “and in doing so demonstrate a dramatic improvement over supercomputers currently in use. So far, quantum computing has just existed as a theoretical possibility. We believe it will be possible to build one, but we also know it will be extremely difficult. If one could be built, it would transform information technology.”
While teams worldwide are working on the design and potential construction of a quantum computer, the new NSF grant will put UGA in the thick of the race and involve the expertise of internationally recognized scientists, including Geller and his colleague in the department of physics and astronomy, Phillip Stancil, who also is a member of the UGA Center for Simulational Physics.
“Conventional computers are very useful now in solving problems in simulational physics,” said Stancil. “But the same problems could often be solved much faster with a quantum computer.”
The theory behind quantum computing has advanced dramatically in the past few years. Whereas it once seemed like a dazzling but impractical approach to computing, breakthroughs now make a functioning quantum computer seem likely in the relatively near future. Still, it will take time before a large-scale quantum computer is at work solving such real-world problems as code breaking.
The key to quantum computing is using clusters of data called qubits (for quantum bits) that handle data differently than conventional computers based on transistors. Traditional computers use a 1 or a 0 to represent “on” or “off” states, but a qubit, which can be constructed in different ways, can represent 1 and 0 states simultaneously in something called superposition.
“We will use this grant to develop and demonstrate a general purpose quantum simulator built from supercomputing electrical circuits,” explained Geller. “We believe that in 10 or 20 years, these general purpose quantum simulators will be stationed at supercomputing centers next to conventional machines and available as an online computational resource for large communities of scientists.”
Since these quantum simulators will be used in tandem with supercomputers, they will be at least as fast as existing technology, but research so far indicates the same problem can be solved much faster using the new arrays.
Among the fields in which such a setup would have a significant impact are atomic and molecular collisions, the actions of cold atomic gases, complex chemical dynamics, low-temperature physics and quantum chemistry.
Just how long it will take to have large-scale quantum computers online remains unclear. A researcher writing in the journal Nature earlier this year, however, presented a hopeful assessment:
“Many of us are reluctant to make predictions about when quantum computers will start to be used productively,” he wrote. “I am optimistic that I will be able to perform interesting computations on quantum devices in my lifetime but would not be disappointed if we encounter unexpected obstacles along the way.”
Such enthusiasm also is obvious in a conversation with Stancil and Geller. They will work closely with co-principal investigators Andrew Sornborger of the UGA department of mathematics and John Martinis of the University of California, Santa Barbara. Of the total amount of the grant, $993,696 will be distributed to UC Santa Barbara.
One potential limiting factor is that the machines must handle data at extremely low temperatures to work-near absolute zero. Still, super-cold environments have been part of research at UGA for years, and the scientists believe such a need could be successfully handled.
When in 1957 scientists Charles Townes and Arthur Schawlow discovered the laser, there was no known use for that powerful beam of light. Now, lasers are used in everything from welding to bloodless surgery. While excitement over the simple construction of a quantum computer drives researchers like Geller and Stancil, the devices may one day have as many uses as the laser.
“I do have a fantasy list of possible things a quantum computer might be able to do,” said Geller. “For instance, it might be useful in understanding more about the rates of decay of elemental particles. But the most exciting thing is just getting from theory to the lab. While we have a long way to go in actually building a quantum computer, we are going much faster than I would have thought on the theory side. We do have the end result in sight now.”