Gravity gets a quantum boost

 作者:赫连花     |      日期:2019-03-15 03:09:00
DESPITE its 300-year history, Newton’s gravitational constant, G, is the least well measured of all the fundamental constants. Now quantum mechanics may help pin down the strength of gravity more precisely. Traditionally, various kinds of torsion balance have been used to calculate G by measuring the twist in a wire induced by the gravitational force between two masses. But this can only provide rough estimates. Mark Kasevich of Stanford University in California and colleagues split a beam of caesium atoms into two using an interferometer,