Washington, Feb 27 (IANS) Quantum computing - a new paradigm in information processing that may complement classical computers, could soon become a reality with physicists successfully creating a circuit using neutral atoms.

Physicists at the University of Wisconsin-Madison created the circuit by exerting delicate control over a pair of atoms within a mere seven-millionths-of-a-second window of opportunity.

UW-Madison physics professor Mark Saffman, with fellow physics professor Thad Walker, successfully used neutral atoms to create what is known as a controlled-NOT (CNOT) gate, a basic type of circuit that will be an essential element of any quantum computer.

The work is the first demonstration of a quantum gate between two uncharged atoms.

The use of neutral atoms rather than charged ions or other materials distinguishes the achievement from previous work.

'The current gold standard in experimental quantum computing has been set by trapped ions... People can run small programs now with up to eight ions in traps,' says Saffman.

However, to be useful for computing applications, systems must contain enough quantum bits, or qubits, to be capable of running long programs and handling more complex calculations.

An ion-based system presents challenges for scaling up because ions are highly interactive with one another and their environment, making them difficult to control.

The physics that describes atoms - quantum mechanics, opens up completely new possibilities for processing information. 'There are certain calculational problems that can be solved exponentially faster on a quantum computer than on any foreseeable classical computer,' Saffman said.

The Wisconsin group is now working toward arrays of up to 50 atoms to test the feasibility of scaling up their methods, says an UW-Madison release.

These findings were published in the January issue of the Physical Review Letters.