Physicists from the Australian National University have developed the most sensitive measurement method
A study published this week inScience magazine, is based on the definition of the color of laser radiation, in which the helium atom is invisible. As the authors of the new work note, the experiment is an independent confirmation of previous methods used to test quantum electrodynamics. Among them is the measurement of transitions from one energy state of an atom to another.
"This invisibility is only fora particular atom and a particular color of light. Therefore, it cannot be used to make the invisibility cloak that Harry Potter used to explore the dark corners of Hogwarts, explains Bryce Henson, lead author of the new work, at the Australian National University Research School of Physics. “But we managed to explore some of the ‘back streets’ of QED theory.”
With an extremely high resolution laserand atoms cooled to 80 billionths of a degree above absolute zero (80 nanokelvins), scientists have achieved sensitivity in energy measurements, which was 5 orders of magnitude less than the energy of atoms, about 10-35 J.
“This is so small that I can’t think of a single phenomenon with which it could be compared,” the author of the study added.
Thanks to these measurements, scientists were able to deducevery accurate values of the invisible color of helium. To compare their results with the theoretical prediction for QED, they turned to Professor Li-Yang Tang from the Chinese Academy of Sciences in Wuhan and Professor Gordon Drake from the University of Windsor in Canada. As a result, scientists achieved that the theoretical value was only slightly lower than the experimental one, and also 1.7 times higher than the experimental error.
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