Physicists in the United States said Wednesday they have developed a simulator that will allow them to observe the behaviour of subatomic particles impossible to measure on existing computers.

Understanding quantum mechanics is a key challenge for scientists seeking to explain natural phenomena on the subatomic level, where the laws of nature work differently to those of the observable world.

"Our simulator's potential calculation power outstrips anything conceivable by human beings. It is absolutely the most powerful simulator ever built," project member Joe Britton told AFP of the National Institute of Standards and Technology (NIST) design.

"Our experiment takes the idea of simulation from the realm of 'toy models' to full-fledged 'quantum simulator'."

A statement said no other scientists have managed to build a simulator that was able to deal with more than 30 quantum particles.

"The NIST simulator has extensive control over hundreds of qubits (quantum bits)," it said -- ten times more than previous devices.

"The simulator has passed a series of important benchmarking tests and scientists are poised to study problems in material science that are impossible to model on conventional computers."