A falling quantum object is subject to the effects of gravity, a new study found yesterday. The finding for the first time confirms a decades-old prediction by Albert Einstein, aligning with his broader theory of gravity.
Physicists sought to probe whether Einstein’s equivalence principle—whereby objects undergo weightlessness in free fall—applies on a quantum level (see 101). To test the question, they used an apparatus that split a quantum wave associated with an atom into two paths, holding one still while projecting the other into free fall. After the experiment, interference between the waves allowed researchers to record a tiny difference in quantum phase aligning with calculations anticipated by Einstein’s theory of gravity. The finding marks the first direct measurement of its kind and suggests that the equivalence principle continues to apply at the quantum level.
While novel, the study does not reconcile the fields of quantum and classical physics. Learn about some of the differences here.
