PARIS (AFP) - Physicists in the United States on Wednesday notched up a lab success in the quest for quantum computers, whose stellar capacities have already earned them the nickname of "super-computers on steroids." Atoms can be excited to a quantum condition using microwaves, an advance over larger and bulkier lasers, until now the only way to achieve this essential state, they said. In theory, it means that quantum computers - if they are commercially feasible - could be as tiny as a small book, the team reported in Nature, the British science journal.