Quantum computers come closer to realityBy ANI
Monday, June 29, 2009
WASHINGTON - A team led by Yale University researchers has created the first rudimentary solid-state quantum processor, taking another step toward the ultimate dream of building a quantum computer.
They also used the two-qubit superconducting chip to successfully run elementary algorithms, such as a simple search, demonstrating quantum information processing with a solid-state device for the first time.
“Our processor can perform only a few very simple quantum tasks, which have been demonstrated before with single nuclei, atoms and photons,” said Robert Schoelkopf, the William A. Norton Professor of Applied Physics and Physics at Yale.
“But this is the first time they’ve been possible in an all-electronic device that looks and feels much more like a regular microprocessor,” he added.
Working with a group of theoretical physicists led by Steven Girvin, the Eugene Higgins Professor of Physics and Applied Physics, the team manufactured two artificial atoms, or qubits (”quantum bits”).
While each qubit is actually made up of a billion aluminum atoms, it acts like a single atom that can occupy two different energy states.
These states are akin to the “1″ and “0″ or “on” and “off” states of regular bits employed by conventional computers.
Because of the counterintuitive laws of quantum mechanics, however, scientists can effectively place qubits in a “superposition” of multiple states at the same time, allowing for greater information storage and processing power.
These sorts of computations, though simple, have not been possible using solid-state qubits until now in part because scientists could not get the qubits to last long enough.
While the first qubits of a decade ago were able to maintain specific quantum states for about a nanosecond, Schoelkopf and his team are now able to maintain theirs for a microsecond-a thousand times longer, which is enough to run the simple algorithms.
To perform their operations, the qubits communicate with one another using a “quantum bus”-photons that transmit information through wires connecting the qubits-previously developed by the Yale group.
“The key that made the two-qubit processor possible was getting the qubits to switch “on” and “off” abruptly, so that they exchanged information quickly and only when the researchers wanted them to,” said Leonardo DiCarlo, a postdoctoral associate in applied physics at Yale’s School of Engineering and Applied Science and lead author of the research paper.
Next, the team will work to connect more qubits to the quantum bus.
“The processing power increases exponentially with each qubit added, so the potential for more advanced quantum computing is enormous,” Schoelkopf said. (ANI)