By counting the number of such X-rays while scanning the frequency of the laser pulse, the team could make a very precise measurement of the photon energy required to drive the 2s-2p transition.
Unlike Mr Khanna, Mr Nye will not make your pulse race. But he is more likely to leave you convinced.
与肯纳先生不同，奈先生不会让你心潮澎湃。但是，他更可能让你深信不疑。
3
"With a laser pulse, you can tap that shell and make it ring like a bell," said physicist Till Rosenband of NIST, who built the existing quantum-logic clock.