Gravity should, in theory, come in tiny packets called gravitons, much as light comes in photons. For decades, estimates said catching even one would need a detector the size of Jupiter. Those estimates assumed a graviton would have to kick a single electron, which almost never happens. In a new paper, physicist Igor Pikovski argues instead that a large vibrating object could absorb a graviton as a whole, which greatly improves the odds. He suggests working at the frequencies LIGO uses, so that LIGO's detections of passing gravitational waves can flag when a graviton might have arrived.
Catching one would be the first direct sign of gravity's smallest units of energy. The author also notes a limit: a detection alone would not prove gravity is quantum, because some non-quantum models could mimic the signal if they give up energy conservation. This extended version of his argument is a preprint and has not been peer reviewed.
