TICK FOR PHYSICS THEORY

PHYSICISTS at the Australian National University have developed the most sensitive method yet for measuring the potential energy of an atom (within a hundredth of a decillionth of a joule – or 10-35 joule) and used it to validate one of the most tested theories in physics – quantum electrodynamics (QED).

The research, published this week in Science, relies on finding the colour of laser light where a helium atom is invisible and is an independent corroboration of previous methods used to test QED, which have involved measuring transitions from one atomic energy state to another.

“This invisibility is only for a specific atom and a specific colour of light – so it couldn’t be used to make an invisibility cloak that Harry Potter would use to investigate dark corners at Hogwarts,” lead author Bryce Henson said.