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august 15, 2000 |
5-qubit quantum computer

Isaac L. Chuang, who led a team of scientists from IBM Research, Stanford University and the University of Calgary, presented his team's latest result today.

"*Quantum computing* begins where Moore's Law ends -- about the year 2020, when circuit features are predicted to be the size of atoms and molecules,'' says Chuang. "Indeed, the basic elements of quantum computers are atoms and molecules.''

Quantum computers get their power by taking advantage of certain quantum physics properties of atoms or nuclei that allow them to work together as quantum bits, or "qubits," to be the computer's processor and memory. The new quantum computer contains five qubits -- five fluorine atoms within a molecule specially designed so the fluorine nuclei's "spins" can interact with each other as qubits, be programmed by radiofrequency pulses and be detected by nuclear magnetic resonance instruments. Using the molecule, Chuang's team solved in one step a mathematical problem for which conventional computers require repeated cycles. The problem is called "order-finding" -- finding the period of a particular function -- which is typical of many basic mathematical problems that underlie important applications such as cryptography. The order-finding result announced today is the most complex algorithm yet to be demonstrated by a quantum computer.

"This result gives us a great deal of confidence in understanding how quantum computing can evolve into a future technology," Chuang says. "It reinforces the growing realization that quantum computers may someday be able to live up to their potential of solving in remarkably short times problems that are so complex that the most powerful supercomputers can't calculate the answers even if they worked on them for millions of years."

When quantum computers were first proposed in the 1970s and 1980s (by theorists such as the late Richard Feynmann of California Institute of Technology; Paul Benioff of Argonne National Laboratory; David Deutsch of Oxford U. in England., and Charles Bennett of IBM's T.J. Watson Research Center), many scientists doubted that they could ever be made practical. But in 1994, Peter Shor of AT&T Research described a specific quantum algorithm for factoring large numbers exponentially faster than conventional computers -- fast enough to break the security of many public-key cryptosystems.
IBM-Led Team Unveils Most-Advanced Quantum Computer
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